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aria-controls="sidenav-5"><span>App solutions</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5"><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-1" role="button" aria-expanded="false" aria-controls="sidenav-5-1"><span>AI</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-1"><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-1-1" role="button" aria-expanded="false" aria-controls="sidenav-5-1-1"><span>AI Toolkit guide</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-1-1"><li class="nav-item"><a class="nav-link" href="/ai-toolkit"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" 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class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-2"><li class="nav-item"><a class="nav-link" href="/data-and-backend/firebase"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://firebase.google.com/docs/flutter" target="_blank" rel="noopener"><div><span>Discover Firebase for Flutter</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://www.youtube.com/watch?v=wUSkeTaBonA" target="_blank" rel="noopener"><div><span>Get to know Firebase for Flutter</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://firebase.google.com/codelabs/firebase-auth-in-flutter-apps" target="_blank" rel="noopener"><div><span>Add a user authentication flow to a Flutter app using FirebaseUI</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://firebase.google.com/codelabs/firebase-get-to-know-web" target="_blank" rel="noopener"><div><span>Get to know Firebase for web</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-3" role="button" aria-expanded="false" aria-controls="sidenav-5-3"><span>Games</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-3"><li class="nav-item"><a class="nav-link" href="/resources/games-toolkit"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/games/achievements-leaderboard"><div><span>Add achievements and leaderboards</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://firebase.google.com/codelabs/build-leaderboards-with-firestore#0" target="_blank" rel="noopener"><div><span>Build leaderboards with Firestore</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/plugins/google-mobile-ads"><div><span>Add advertising</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/games/firestore-multiplayer"><div><span>Add multiplayer support</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://codelabs.developers.google.com/codelabs/flutter-in-app-purchases" target="_blank" rel="noopener"><div><span>Add in-app purchases</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://firebase.google.com/codelabs/firebase-auth-in-flutter-apps" target="_blank" rel="noopener"><div><span>Add user authentication</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://firebase.google.com/docs/crashlytics/get-started?platform=flutter" target="_blank" rel="noopener"><div><span>Debug using Crashlytics</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://codelabs.developers.google.com/codelabs/flutter-flame-brick-breaker" target="_blank" rel="noopener"><div><span>Intro to Flame with Flutter</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-4" role="button" aria-expanded="false" aria-controls="sidenav-5-4"><span>Monetization</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-4"><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-4-1" role="button" aria-expanded="false" aria-controls="sidenav-5-4-1"><span>Advertising</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-4-1"><li class="nav-item"><a class="nav-link" href="/resources/ads-overview"><div><span>Ads overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/plugins/google-mobile-ads"><div><span>Add advertising</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://codelabs.developers.google.com/codelabs/admob-ads-in-flutter" target="_blank" rel="noopener"><div><span>Add AdMob ads to your Flutter app</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://codelabs.developers.google.com/codelabs/admob-inline-ads-in-flutter" target="_blank" rel="noopener"><div><span>Add an AdMob banner and native inline ads</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://developers.google.com/admob/flutter/mediation" target="_blank" rel="noopener"><div><span>Google AdMob mediation</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://pub.dev/packages/interactive_media_ads" target="_blank" rel="noopener"><div><span>Interactive Media Ads SDK</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-4-2" role="button" aria-expanded="false" aria-controls="sidenav-5-4-2"><span>In-app purchases</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-4-2"><li class="nav-item"><a class="nav-link" href="/resources/in-app-purchases-overview"><div><span>In-app purchases overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://codelabs.developers.google.com/codelabs/flutter-in-app-purchases" target="_blank" rel="noopener"><div><span>Add in-app purchases</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-4-3" role="button" aria-expanded="false" aria-controls="sidenav-5-4-3"><span>Payments</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-4-3"><li class="nav-item"><a class="nav-link" href="/resources/payments-overview"><div><span>Payments overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://pub.dev/packages/pay" target="_blank" rel="noopener"><div><span>Google pay package</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-5" role="button" aria-expanded="false" aria-controls="sidenav-5-5"><span>Maps</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-5"><li class="nav-item"><a class="nav-link" href="https://codelabs.developers.google.com/codelabs/google-maps-in-flutter" target="_blank" rel="noopener"><div><span>Add Google maps to a Flutter app</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://developers.google.com/maps/flutter-package" target="_blank" rel="noopener"><div><span>Google Maps package</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-5-6" role="button" aria-expanded="false" aria-controls="sidenav-5-6"><span>News</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-5-6"><li class="nav-item"><a class="nav-link" href="/resources/news-toolkit"><div><span>Build a news app</span></div></a></li></ul></li></ul></li><li aria-hidden="true"><div class="sidenav-divider"></div></li><li class="nav-header">User interface</li><li class="nav-item"><a class="nav-link" href="/ui"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/widgets"><div><span>Widget catalog</span></div></a></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-10" role="button" aria-expanded="false" aria-controls="sidenav-10"><span>Layout</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-10"><li class="nav-item"><a class="nav-link" href="/ui/layout"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/layout/tutorial"><div><span>Build a layout</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-10-3" role="button" aria-expanded="false" aria-controls="sidenav-10-3"><span>Lists & grids</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-10-3"><li class="nav-item"><a class="nav-link" href="/cookbook/lists/basic-list"><div><span>Create and use lists</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/lists/horizontal-list"><div><span>Create a horizontal list</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/lists/grid-lists"><div><span>Create a grid view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/lists/mixed-list"><div><span>Create lists with different types of items</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/lists/spaced-items"><div><span>Create lists with spaced items</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/lists/long-lists"><div><span>Work with long lists</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-10-4" role="button" aria-expanded="false" aria-controls="sidenav-10-4"><span>Scrolling</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-10-4"><li class="nav-item"><a class="nav-link" href="/ui/layout/scrolling"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/layout/scrolling/slivers"><div><span>Use slivers to achieve fancy scrolling</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/lists/floating-app-bar"><div><span>Place a floating app bar above a list</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/effects/parallax-scrolling"><div><span>Create a scrolling parallax effect</span></div></a></li></ul></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-11" role="button" aria-expanded="false" aria-controls="sidenav-11"><span>Adaptive & responsive design</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-11"><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/general"><div><span>General approach</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/safearea-mediaquery"><div><span>SafeArea & MediaQuery</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/large-screens"><div><span>Large screens & foldables</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/input"><div><span>User input & accessibility</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/capabilities"><div><span>Capabilities & policies</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/platform-adaptations"><div><span>Automatic platform adaptations</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/best-practices"><div><span>Best practices</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/adaptive-responsive/more-info"><div><span>Additional resources</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-12" role="button" aria-expanded="false" aria-controls="sidenav-12"><span>Design & theming</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-12"><li class="nav-item"><a class="nav-link" href="/cookbook/design/themes"><div><span>Share styles with themes</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/design/material"><div><span>Material design</span></div></a></li><li class="nav-item"><a class="nav-link" href="/release/breaking-changes/material-3-migration"><div><span>Migrate to Material 3</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-12-4" role="button" aria-expanded="false" aria-controls="sidenav-12-4"><span>Text</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-12-4"><li class="nav-item"><a class="nav-link" href="/ui/design/text/typography"><div><span>Fonts & typography</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/design/fonts"><div><span>Use a custom font</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/design/package-fonts"><div><span>Export fonts from a package</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://pub.dev/packages/google_fonts" target="_blank" rel="noopener"><div><span>Google Fonts package</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-12-5" role="button" aria-expanded="false" aria-controls="sidenav-12-5"><span>Custom graphics</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-12-5"><li class="nav-item"><a class="nav-link" href="/ui/design/graphics/fragment-shaders"><div><span>Use custom fragment shaders</span></div></a></li></ul></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-13" role="button" aria-expanded="false" aria-controls="sidenav-13"><span>Interactivity</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-13"><li class="nav-item"><a class="nav-link" href="/ui/interactivity"><div><span>Add interactivity to your app</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-13-2" role="button" aria-expanded="false" aria-controls="sidenav-13-2"><span>Gestures</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-13-2"><li class="nav-item"><a class="nav-link" href="/ui/interactivity/gestures"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/gestures/handling-taps"><div><span>Handle taps</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/interactivity/gestures/drag-outside"><div><span>Drag an object outside an app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/effects/drag-a-widget"><div><span>Drag a UI element within an app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/gestures/ripples"><div><span>Add Material touch ripples</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/gestures/dismissible"><div><span>Implement swipe to dismiss</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-13-3" role="button" aria-expanded="false" aria-controls="sidenav-13-3"><span>Input & forms</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-13-3"><li class="nav-item"><a class="nav-link" href="/cookbook/forms/text-input"><div><span>Create and style a text field</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/forms/retrieve-input"><div><span>Retrieve the value of a text field</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/forms/text-field-changes"><div><span>Handle changes to a text field</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/forms/focus"><div><span>Manage focus in text fields</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/forms/validation"><div><span>Build a form with validation</span></div></a></li></ul></li><li class="nav-item"><a class="nav-link" href="/cookbook/design/snackbars"><div><span>Display a snackbar</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/interactivity/actions-and-shortcuts"><div><span>Implement actions & shortcuts</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/interactivity/focus"><div><span>Manage keyboard focus</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-14" role="button" aria-expanded="false" aria-controls="sidenav-14"><span>Assets & media</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-14"><li class="nav-item"><a class="nav-link" href="/ui/assets/assets-and-images"><div><span>Add assets and images</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/images/network-image"><div><span>Display images from the internet</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/images/fading-in-images"><div><span>Fade in images with a placeholder</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/plugins/play-video"><div><span>Play and pause a video</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/assets/asset-transformation"><div><span>Transform assets at build time</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-15" role="button" aria-expanded="false" aria-controls="sidenav-15"><span>Navigation & routing</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-15"><li class="nav-item"><a class="nav-link" href="/ui/navigation"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/design/tabs"><div><span>Add tabs to your app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/navigation/navigation-basics"><div><span>Navigate to a new screen and back</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/navigation/passing-data"><div><span>Send data to a new screen</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/navigation/returning-data"><div><span>Return data from a screen</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/design/drawer"><div><span>Add a drawer to a screen</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/navigation/deep-linking"><div><span>Set up deep linking</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/navigation/set-up-app-links"><div><span>Set up app links for Android</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/navigation/set-up-universal-links"><div><span>Set up universal links for iOS</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/navigation/url-strategies"><div><span>Configure web URL strategies</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-16" role="button" aria-expanded="false" aria-controls="sidenav-16"><span>Animations & transitions</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-16"><li class="nav-item"><a class="nav-link" href="/ui/animations"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/animations/tutorial"><div><span>Tutorial</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/animations/implicit-animations"><div><span>Implicit animations</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/animation/animated-container"><div><span>Animate the properties of a container</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/animation/opacity-animation"><div><span>Fade a widget in and out</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/animations/hero-animations"><div><span>Hero animations</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/animation/page-route-animation"><div><span>Animate a page route transition</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/animation/physics-simulation"><div><span>Animate using a physics simulation</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/animations/staggered-animations"><div><span>Staggered animations</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/effects/staggered-menu-animation"><div><span>Create a staggered menu animation</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/animations/overview"><div><span>API overview</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-17" role="button" aria-expanded="false" aria-controls="sidenav-17"><span>Accessibility & internationalization</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-17"><li class="nav-item"><a class="nav-link" href="/ui/accessibility-and-internationalization/accessibility"><div><span>Accessibility</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/accessibility-and-internationalization/internationalization"><div><span>Internationalization</span></div></a></li></ul></li><li aria-hidden="true"><div class="sidenav-divider"></div></li><li class="nav-header">Beyond UI</li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-20" role="button" aria-expanded="false" aria-controls="sidenav-20"><span>Data & backend</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-20"><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-20-1" role="button" aria-expanded="false" aria-controls="sidenav-20-1"><span>State management</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-20-1"><li class="nav-item"><a class="nav-link" href="/data-and-backend/state-mgmt/intro"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/data-and-backend/state-mgmt/declarative"><div><span>Think declaratively</span></div></a></li><li class="nav-item"><a class="nav-link" href="/data-and-backend/state-mgmt/ephemeral-vs-app"><div><span>Ephemeral vs app state</span></div></a></li><li class="nav-item"><a class="nav-link" href="/data-and-backend/state-mgmt/simple"><div><span>Simple app state management</span></div></a></li><li class="nav-item"><a class="nav-link" href="/data-and-backend/state-mgmt/options"><div><span>Options</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-20-2" role="button" aria-expanded="false" aria-controls="sidenav-20-2"><span>Networking & http</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-20-2"><li class="nav-item"><a class="nav-link" href="/data-and-backend/networking"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/networking/fetch-data"><div><span>Fetch data from the internet</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/networking/authenticated-requests"><div><span>Make authenticated requests</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/networking/send-data"><div><span>Send data to the internet</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/networking/update-data"><div><span>Update data over the internet</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/networking/delete-data"><div><span>Delete data on the internet</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/networking/web-sockets"><div><span>Communicate with WebSockets</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-20-3" role="button" aria-expanded="false" aria-controls="sidenav-20-3"><span>Serialization</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-20-3"><li class="nav-item"><a class="nav-link" href="/data-and-backend/serialization/json"><div><span>JSON serialization</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/networking/background-parsing"><div><span>Parse JSON in the background</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-20-4" role="button" aria-expanded="false" aria-controls="sidenav-20-4"><span>Persistence</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-20-4"><li class="nav-item"><a class="nav-link" href="/cookbook/persistence/key-value"><div><span>Store key-value data on disk</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/persistence/reading-writing-files"><div><span>Read and write files</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/persistence/sqlite"><div><span>Persist data with SQLite</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-20-5" role="button" aria-expanded="false" aria-controls="sidenav-20-5"><span>Firebase</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-20-5"><li class="nav-item"><a class="nav-link" href="/data-and-backend/firebase"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://firebase.google.com/docs/flutter/setup" target="_blank" rel="noopener"><div><span>Add Firebase to your Flutter app</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><a class="nav-link" href="/data-and-backend/google-apis"><div><span>Google APIs</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-21" role="button" aria-expanded="false" aria-controls="sidenav-21"><span>App architecture</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-21"><li class="nav-item"><a class="nav-link" href="/app-architecture"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/app-architecture/concepts"><div><span>Architecture concepts</span></div></a></li><li class="nav-item"><a class="nav-link" href="/app-architecture/guide"><div><span>Guide to app architecture</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-21-4" role="button" aria-expanded="false" aria-controls="sidenav-21-4"><span>Architecture case study</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-21-4"><li class="nav-item"><a class="nav-link" href="/app-architecture/case-study"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/app-architecture/case-study/ui-layer"><div><span>UI layer</span></div></a></li><li class="nav-item"><a class="nav-link" href="/app-architecture/case-study/data-layer"><div><span>Data layer</span></div></a></li><li class="nav-item"><a class="nav-link" href="/app-architecture/case-study/dependency-injection"><div><span>Dependency injection</span></div></a></li><li class="nav-item"><a class="nav-link" href="/app-architecture/case-study/testing"><div><span>Testing each layer</span></div></a></li></ul></li><li class="nav-item"><a class="nav-link" href="/app-architecture/recommendations"><div><span>Recommendations</span></div></a></li><li class="nav-item"><a class="nav-link" href="/app-architecture/design-patterns"><div><span>Design patterns</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-22" role="button" aria-expanded="false" aria-controls="sidenav-22"><span>Platform integration</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-22"><li class="nav-item"><a class="nav-link" href="/reference/supported-platforms"><div><span>Supported platforms</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/desktop"><div><span>Build desktop apps with Flutter</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/platform-channels"><div><span>Write platform-specific code</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-22-4" role="button" aria-expanded="false" aria-controls="sidenav-22-4"><span>Android</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-22-4"><li class="nav-item"><a class="nav-link" href="/platform-integration/android/install-android"><div><span>Add Android as build target</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/splash-screen"><div><span>Add a splash screen</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/predictive-back"><div><span>Add predictive back</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/c-interop"><div><span>Bind to native code</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/platform-views"><div><span>Host a native Android view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/call-jetpack-apis"><div><span>Calling JetPack APIs</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/compose-activity"><div><span>Launch a Jetpack Compose activity</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/restore-state-android"><div><span>Restore state on Android</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/android/chromeos"><div><span>Target ChromeOS with Android</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-22-5" role="button" aria-expanded="false" aria-controls="sidenav-22-5"><span>iOS</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-22-5"><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/install-ios"><div><span>Add iOS as build target</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/ios-latest"><div><span>Flutter on latest iOS</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/apple-frameworks"><div><span>Leverage Apple's system libraries</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/launch-screen"><div><span>Add a launch screen</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/ios-app-clip"><div><span>Add iOS App Clip support</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/app-extensions"><div><span>Add iOS app extensions</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/c-interop"><div><span>Bind to native code</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/platform-views"><div><span>Host a native iOS view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/ios-debugging"><div><span>Enable debugging on iOS</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/ios/restore-state-ios"><div><span>Restore state on iOS</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-22-6" role="button" aria-expanded="false" aria-controls="sidenav-22-6"><span>Linux</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-22-6"><li class="nav-item"><a class="nav-link" href="/platform-integration/linux/install-linux"><div><span>Add Linux as build target</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/linux/building"><div><span>Build a Linux app</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-22-7" role="button" aria-expanded="false" aria-controls="sidenav-22-7"><span>macOS</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-22-7"><li class="nav-item"><a class="nav-link" href="/platform-integration/macos/install-macos"><div><span>Add macOS as build target</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/macos/building"><div><span>Build a macOS app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/macos/c-interop"><div><span>Bind to native code</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/macos/platform-views"><div><span>Host a native macOS view</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-22-8" role="button" aria-expanded="false" aria-controls="sidenav-22-8"><span>Web</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-22-8"><li class="nav-item"><a class="nav-link" href="/platform-integration/web"><div><span>Web support in Flutter</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/install-web"><div><span>Add web as build target</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/building"><div><span>Build a web app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/wasm"><div><span>Compile to WebAssembly</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/initialization"><div><span>Customize app initialization</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/embedding-flutter-web"><div><span>Add Flutter to any web app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/web-content-in-flutter"><div><span>Web content in Flutter</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/renderers"><div><span>Web renderers</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/web-images"><div><span>Display images on the web</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/faq"><div><span>Web FAQ</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-22-9" role="button" aria-expanded="false" aria-controls="sidenav-22-9"><span>Windows</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-22-9"><li class="nav-item"><a class="nav-link" href="/platform-integration/windows/install-windows"><div><span>Add Windows as build target</span></div></a></li><li class="nav-item"><a class="nav-link" href="/platform-integration/windows/building"><div><span>Build a Windows app</span></div></a></li></ul></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-23" role="button" aria-expanded="false" aria-controls="sidenav-23"><span>Packages & plugins</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-23"><li class="nav-item"><a class="nav-link" href="/packages-and-plugins/using-packages"><div><span>Use packages & plugins</span></div></a></li><li class="nav-item"><a class="nav-link" href="/packages-and-plugins/developing-packages"><div><span>Develop packages & plugins</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-23-3" role="button" aria-expanded="false" aria-controls="sidenav-23-3"><span>Swift Package Manager</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-23-3"><li class="nav-item"><a class="nav-link" href="/packages-and-plugins/swift-package-manager/for-app-developers"><div><span>For app developers</span></div></a></li><li class="nav-item"><a class="nav-link" href="/packages-and-plugins/swift-package-manager/for-plugin-authors"><div><span>For plugin authors</span></div></a></li></ul></li><div class="sidenav-divider"></div><li class="nav-item"><a class="nav-link" href="/packages-and-plugins/favorites"><div><span>Flutter Favorites</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://pub.dev/flutter" target="_blank" rel="noopener"><div><span>Package repository</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link active collapsible" data-toggle="collapse" data-target="#sidenav-24" role="button" aria-expanded="true" aria-controls="sidenav-24"><span>Testing & debugging</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse show" id="sidenav-24"><li class="nav-header">Testing</li><li class="nav-item"><a class="nav-link" href="/testing/overview"><div><span>Overview</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-24-3" role="button" aria-expanded="false" aria-controls="sidenav-24-3"><span>Unit testing</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-24-3"><li class="nav-item"><a class="nav-link" href="/cookbook/testing/unit/introduction"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/testing/unit/mocking"><div><span>Mock dependencies</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-24-4" role="button" aria-expanded="false" aria-controls="sidenav-24-4"><span>Widget testing</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-24-4"><li class="nav-item"><a class="nav-link" href="/cookbook/testing/widget/introduction"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/testing/widget/finders"><div><span>Find widgets</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/testing/widget/scrolling"><div><span>Simulate scrolling</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/testing/widget/tap-drag"><div><span>Simulate user interaction</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-24-5" role="button" aria-expanded="false" aria-controls="sidenav-24-5"><span>Integration testing</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-24-5"><li class="nav-item"><a class="nav-link" href="/cookbook/testing/integration/introduction"><div><span>Introduction</span></div></a></li><li class="nav-item"><a class="nav-link" href="/testing/integration-tests"><div><span>Write and run an integration test</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/testing/integration/profiling"><div><span>Profile an integration test</span></div></a></li></ul></li><li class="nav-item"><a class="nav-link" href="/testing/testing-plugins"><div><span>Test a plugin</span></div></a></li><li class="nav-item"><a class="nav-link" href="/testing/plugins-in-tests"><div><span>Handle plugin code in tests</span></div></a></li><li class="nav-header">Debugging</li><li class="nav-item"><a class="nav-link" href="/testing/debugging"><div><span>Debugging tools</span></div></a></li><li class="nav-item"><a class="nav-link" href="/testing/code-debugging"><div><span>Debug your app programmatically</span></div></a></li><li class="nav-item"><a class="nav-link" href="/testing/native-debugging"><div><span>Use a native language debugger</span></div></a></li><li class="nav-item"><a class="nav-link active" href="/testing/common-errors"><div><span>Common Flutter errors</span></div></a></li><li class="nav-item"><a class="nav-link" href="/testing/errors"><div><span>Handle errors</span></div></a></li><li class="nav-item"><a class="nav-link" href="/cookbook/maintenance/error-reporting"><div><span>Report errors to a service</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-25" role="button" aria-expanded="false" aria-controls="sidenav-25"><span>Performance & optimization</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-25"><li class="nav-item"><a class="nav-link" href="/perf"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/impeller"><div><span>Impeller</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/best-practices"><div><span>Performance best practices</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/app-size"><div><span>App size</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/deferred-components"><div><span>Deferred components</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/rendering-performance"><div><span>Rendering performance</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/ui-performance"><div><span>Performance profiling</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/web-performance"><div><span>Performance profiling for web</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/metrics"><div><span>Performance metrics</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/isolates"><div><span>Concurrency and isolates</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/faq"><div><span>Performance FAQ</span></div></a></li><li class="nav-item"><a class="nav-link" href="/perf/appendix"><div><span>Appendix</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-26" role="button" aria-expanded="false" aria-controls="sidenav-26"><span>Deployment</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-26"><li class="nav-item"><a class="nav-link" href="/deployment/obfuscate"><div><span>Obfuscate Dart code</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/flavors"><div><span>Create app flavors for Android</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/flavors-ios"><div><span>Create app flavors for iOS and macOS</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/android"><div><span>Build and release an Android app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/ios"><div><span>Build and release an iOS app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/macos"><div><span>Build and release a macOS app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/linux"><div><span>Build and release a Linux app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/windows"><div><span>Build and release a Windows app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/web"><div><span>Build and release a web app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/deployment/cd"><div><span>Set up continuous deployment</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-27" role="button" aria-expanded="false" aria-controls="sidenav-27"><span>Add to an existing app</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-27"><li class="nav-item"><a class="nav-link" href="/add-to-app"><div><span>Introduction</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-27-2" role="button" aria-expanded="false" aria-controls="sidenav-27-2"><span>Add to an Android app</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-27-2"><li class="nav-item"><a class="nav-link" href="/add-to-app/android/project-setup"><div><span>Set up Android project</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/android/add-flutter-screen"><div><span>Add a single Flutter screen</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/android/add-flutter-fragment"><div><span>Add a Flutter Fragment</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/android/add-flutter-view"><div><span>Add a Flutter View</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/android/plugin-setup"><div><span>Use a Flutter plugin</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-27-3" role="button" aria-expanded="false" aria-controls="sidenav-27-3"><span>Add to an iOS app</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-27-3"><li class="nav-item"><a class="nav-link" href="/add-to-app/ios/project-setup"><div><span>Set up iOS project</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/ios/add-flutter-screen"><div><span>Add a single Flutter screen</span></div></a></li></ul></li><li class="nav-item"><a class="nav-link" href="/platform-integration/web/embedding-flutter-web"><div><span>Add to a web app</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/debugging"><div><span>Debug embedded Flutter module</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/multiple-flutters"><div><span>Add multiple Flutter instances</span></div></a></li><li class="nav-item"><a class="nav-link" href="/add-to-app/performance"><div><span>Loading sequence and performance</span></div></a></li></ul></li><li aria-hidden="true"><div class="sidenav-divider"></div></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-29" role="button" aria-expanded="false" aria-controls="sidenav-29"><span>Tools & editors</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-29"><li class="nav-item"><a class="nav-link" href="/tools/android-studio"><div><span>Android Studio & IntelliJ</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/vs-code"><div><span>Visual Studio Code</span></div></a></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-29-3" role="button" aria-expanded="false" aria-controls="sidenav-29-3"><span>DevTools</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-29-3"><li class="nav-item"><a class="nav-link" href="/tools/devtools"><div><span>Overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/android-studio"><div><span>Run from Android Studio & IntelliJ</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/vscode"><div><span>Run from VS Code</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/cli"><div><span>Run from command line</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/inspector"><div><span>Flutter inspector</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/legacy-inspector"><div><span>Legacy Flutter inspector</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/performance"><div><span>Performance view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/cpu-profiler"><div><span>CPU Profiler view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/memory"><div><span>Memory view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/console"><div><span>Debug console view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/network"><div><span>Network view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/debugger"><div><span>Debugger</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/logging"><div><span>Logging view</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/app-size"><div><span>App size tool</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/extensions"><div><span>DevTools extensions</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/deep-links"><div><span>Validate deep links</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/devtools/release-notes"><div><span>Release notes</span></div></a></li></ul></li><li class="nav-item"><a class="nav-link" href="/tools/sdk"><div><span>SDK overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/pubspec"><div><span>Flutter's pubspec options</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/flutter-fix"><div><span>Automated fixes</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/formatting"><div><span>Code formatting</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-30" role="button" aria-expanded="false" aria-controls="sidenav-30"><span>Flutter concepts</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-30"><li class="nav-item"><a class="nav-link" href="/resources/architectural-overview"><div><span>Architectural overview</span></div></a></li><li class="nav-item"><a class="nav-link" href="/resources/inside-flutter"><div><span>Inside Flutter</span></div></a></li><li class="nav-item"><a class="nav-link" href="/ui/layout/constraints"><div><span>Understanding constraints</span></div></a></li><li class="nav-item"><a class="nav-link" href="/testing/build-modes"><div><span>Flutter's build modes</span></div></a></li><li class="nav-item"><a class="nav-link" href="/tools/hot-reload"><div><span>Hot reload</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsed collapsible" data-toggle="collapse" data-target="#sidenav-31" role="button" aria-expanded="false" aria-controls="sidenav-31"><span>Resources</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-31"><li class="nav-item"><a class="nav-link" href="/resources/faq"><div><span>FAQ</span></div></a></li><li class="nav-item"><a class="nav-link" href="/resources/books"><div><span>Books</span></div></a></li><li class="nav-item"><a class="nav-link" href="/resources/videos"><div><span>Videos</span></div></a></li><li class="nav-item"><a class="nav-link" href="/resources/courses"><div><span>Courses</span></div></a></li><li class="nav-item"><a class="nav-link" href="/resources/bootstrap-into-dart"><div><span>Learn Dart</span></div></a></li><li class="nav-item"><a class="nav-link" href="/resources/support"><div><span>Get support</span></div></a></li><div class="sidenav-divider"></div><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-31-8" role="button" aria-expanded="false" aria-controls="sidenav-31-8"><span>Contribute</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-31-8"><li class="nav-item"><a class="nav-link" href="/resources/bug-reports"><div><span>Create useful bug reports</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://github.com/flutter/flutter/blob/main/CONTRIBUTING.md" target="_blank" rel="noopener"><div><span>Contribute to Flutter</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="/resources/design-docs"><div><span>Discover proposed features</span></div></a></li></ul></li><li class="nav-item"><button class="nav-link collapsible collapsed" data-toggle="collapse" data-target="#sidenav-31-9" role="button" aria-expanded="false" aria-controls="sidenav-31-9"><span>Reference</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" id="sidenav-31-9"><li class="nav-item"><a class="nav-link" href="/dash"><div><span>Who is Dash?</span></div></a></li><li class="nav-item"><a class="nav-link" href="/reference/widgets"><div><span>Widget index</span></div></a></li><li class="nav-item"><a class="nav-link" href="/reference/flutter-cli"><div><span>flutter CLI</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://api.flutter.dev" target="_blank" rel="noopener"><div><span>API docs</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li></ul></li></ul></nav></div><main class="site-content"><div id="site-toc--side" class="site-toc"><header class="site-toc__title">Contents</header><ul class="section-nav"><li class="toc-entry nav-item"><a class="nav-link" href="#introduction">Introduction</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#a-solid-red-or-grey-screen-when-running-your-app">A solid red or grey screen when running your app</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#a-renderflex-overflowed">'A RenderFlex overflowed…'</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#renderbox-was-not-laid-out">'RenderBox was not laid out'</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#vertical-viewport-was-given-unbounded-height">'Vertical viewport was given unbounded height'</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#an-inputdecorator-cannot-have-an-unbounded-width">'An InputDecorator...cannot have an unbounded width'</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#incorrect-use-of-parentdata-widget">'Incorrect use of ParentData widget'</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#setstate-called-during-build">'setState called during build'</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#the-scrollcontroller-is-attached-to-multiple-scroll-views">The ScrollController is attached to multiple scroll views</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#references">References</a></li></ul></div><article><header class="site-content__title"><h1 id="document-title">Common Flutter errors</h1><nav class="breadcrumbs" aria-label="breadcrumb"><ol vocab="https://schema.org/" typeof="BreadcrumbList"><li class="breadcrumb-item" property="itemListElement" typeof="ListItem"><a href="/testing" property="item" typeof="WebPage"><span property="name">Testing & debugging</span></a><meta property="position" content="0"><span class="material-symbols child-icon" aria-hidden="true">chevron_right</span></li><li class="breadcrumb-item active" property="itemListElement" typeof="ListItem" aria-current="page"><a href="/testing/common-errors" property="item" typeof="WebPage"><span property="name">Common Flutter errors</span></a><meta property="position" content="1"></li></ol></nav></header><div id="site-toc--inline" class="site-toc"><header class="site-toc__title">Contents</header><ul class="section-nav"><li class="toc-entry"><a href="#introduction">Introduction</a></li><li class="toc-entry"><a href="#a-solid-red-or-grey-screen-when-running-your-app">A solid red or grey screen when running your app</a></li><li class="toc-entry"><a href="#a-renderflex-overflowed">'A RenderFlex overflowed…'</a></li><li class="toc-entry"><a href="#renderbox-was-not-laid-out">'RenderBox was not laid out'</a></li><li class="toc-entry"><a href="#vertical-viewport-was-given-unbounded-height">'Vertical viewport was given unbounded height'</a></li><li class="toc-entry"><a href="#an-inputdecorator-cannot-have-an-unbounded-width">'An InputDecorator...cannot have an unbounded width'</a></li><li class="toc-entry"><a href="#incorrect-use-of-parentdata-widget">'Incorrect use of ParentData widget'</a></li><li class="toc-entry"><a href="#setstate-called-during-build">'setState called during build'</a></li><li class="toc-entry"><a href="#the-scrollcontroller-is-attached-to-multiple-scroll-views">The ScrollController is attached to multiple scroll views</a></li><li class="toc-entry"><a href="#references">References</a></li></ul></div> <?code-excerpt path-base="testing/common_errors"?> <div class="header-wrapper"><h2 id="introduction">Introduction</h2><a class="heading-link" href="#introduction" aria-label="Link to 'Introduction' section">#</a></div><p>This page explains several frequently-encountered Flutter framework errors (including layout errors) and gives suggestions on how to resolve them. This is a living document with more errors to be added in future revisions, and your contributions are welcomed. Feel free to <a href="https://github.com/flutter/website/issues/new/choose">open an issue</a> or <a href="https://github.com/flutter/website/pulls">submit a pull request</a> to make this page more useful to you and the Flutter community.</p><div class="header-wrapper"><h2 id="a-solid-red-or-grey-screen-when-running-your-app">A solid red or grey screen when running your app</h2><a class="heading-link" href="#a-solid-red-or-grey-screen-when-running-your-app" aria-label="Link to 'A solid red or grey screen when running your app' section">#</a></div><p>Typically called a "red (or grey) screen of death", this is sometimes how Flutter lets you know that there's an error.</p><p>The red screen can appear when the app runs in debug or profile mode. The grey screen can appear when the app runs in release mode.</p><p>Generally, these errors occur when there's an uncaught exception (and you might need another try-catch block), or when there is some rendering error, such as an overflow error.</p><p>The following articles provide some useful insights on debugging this sort of error:</p><ul><li><a href="https://medium.com/@hpatilabhi10/flutter-errors-demystified-red-screen-errors-vs-debug-console-errors-acb3b8ed2625">Flutter errors demystified</a> by Abishek</li><li><a href="https://medium.com/@LordChris/understanding-and-addressing-the-grey-screen-in-flutter-5e72c31f408f">Understanding and addressing the grey screen in Flutter</a> by Christopher Nwosu-Madueke</li><li><a href="https://www.dhiwise.com/post/flutter-stuck-on-white-screen-understanding-and-fixing">Flutter stuck on white screen</a> by Kesar Bhimani</li></ul><div class="header-wrapper"><h2 id="a-renderflex-overflowed">'A RenderFlex overflowed…'</h2><a class="heading-link" href="#a-renderflex-overflowed" aria-label="Link to ''A RenderFlex overflowed…'' section">#</a></div><p>RenderFlex overflow is one of the most frequently encountered Flutter framework errors, and you've probably run into it already.</p><p><strong>What does the error look like?</strong></p><p>When it happens, yellow and black stripes appear, indicating the area of overflow in the app UI. In addition, an error message displays in the debug console:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>The following assertion was thrown during layout:</span></span> <span class="line"><span>A RenderFlex overflowed by 1146 pixels on the right.</span></span> <span class="line"><span></span></span> <span class="line"><span>The relevant error-causing widget was</span></span> <span class="line"><span></span></span> <span class="line"><span> Row lib/errors/renderflex_overflow_column.dart:23</span></span> <span class="line"><span></span></span> <span class="line"><span>The overflowing RenderFlex has an orientation of Axis.horizontal.</span></span> <span class="line"><span>The edge of the RenderFlex that is overflowing has been marked in the rendering </span></span> <span class="line"><span>with a yellow and black striped pattern. This is usually caused by the contents </span></span> <span class="line"><span>being too big for the RenderFlex.</span></span> <span class="line"><span>(Additional lines of this message omitted)</span></span></code></pre></div></div><p><strong>How might you run into this error?</strong></p><p>The error often occurs when a <code>Column</code> or <code>Row</code> has a child widget that isn't constrained in its size. For example, the code snippet below demonstrates a common scenario:</p> <?code-excerpt "lib/renderflex_overflow.dart (problem)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#0468D7">Widget</span><span style="color:#6200EE"> build</span><span style="color:#222222">(</span><span style="color:#0468D7">BuildContext</span><span style="color:#222222"> context) {</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#0468D7"> Row</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> children: [</span></span> <span class="line"><span style="color:#BD2314"> const</span><span style="color:#0468D7"> Icon</span><span style="color:#222222">(</span><span style="color:#0468D7">Icons</span><span style="color:#222222">.message),</span></span> <span class="line"><span style="color:#0468D7"> Column</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> mainAxisSize: </span><span style="color:#0468D7">MainAxisSize</span><span style="color:#222222">.min,</span></span> <span class="line"><span style="color:#222222"> crossAxisAlignment: </span><span style="color:#0468D7">CrossAxisAlignment</span><span style="color:#222222">.start,</span></span> <span class="line"><span style="color:#222222"> children: [</span></span> <span class="line"><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Title'</span><span style="color:#222222">, style: </span><span style="color:#0468D7">Theme</span><span style="color:#222222">.</span><span style="color:#6200EE">of</span><span style="color:#222222">(context).textTheme.headlineMedium),</span></span> <span class="line"><span style="color:#BD2314"> const</span><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#0C7064"> 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed '</span></span> <span class="line"><span style="color:#0C7064"> 'do eiusmod tempor incididunt ut labore et dolore magna '</span></span> <span class="line"><span style="color:#0C7064"> 'aliqua. Ut enim ad minim veniam, quis nostrud '</span></span> <span class="line"><span style="color:#0C7064"> 'exercitation ullamco laboris nisi ut aliquip ex ea '</span></span> <span class="line"><span style="color:#0C7064"> 'commodo consequat.'</span><span style="color:#222222">,</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ],</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ],</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>In the above example, the <code>Column</code> tries to be wider than the space the <code>Row</code> (its parent) can allocate to it, causing an overflow error. Why does the <code>Column</code> try to do that? To understand this layout behavior, you need to know how Flutter framework performs layout:</p><p>"<em>To perform layout, Flutter walks the render tree in a depth-first traversal and <strong>passes down size constraints</strong> from parent to child… Children respond by <strong>passing up a size</strong> to their parent object within the constraints the parent established.</em>" – <a href="/resources/architectural-overview#layout-and-rendering">Flutter architectural overview</a></p><p>In this case, the <code>Row</code> widget doesn't constrain the size of its children, nor does the <code>Column</code> widget. Lacking constraints from its parent widget, the second <code>Text</code> widget tries to be as wide as all the characters it needs to display. The self-determined width of the <code>Text</code> widget then gets adopted by the <code>Column</code>, which clashes with the maximum amount of horizontal space its parent, the <code>Row</code> widget, can provide.</p><p><strong>How to fix it?</strong></p><p>Well, you need to make sure the <code>Column</code> won't attempt to be wider than it can be. To achieve this, you need to constrain its width. One way to do it is to wrap the <code>Column</code> in an <code>Expanded</code> widget:</p> <?code-excerpt "lib/renderflex_overflow.dart (solution)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#BD2314">return</span><span style="color:#BD2314"> const</span><span style="color:#0468D7"> Row</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> children: [</span></span> <span class="line"><span style="color:#0468D7"> Icon</span><span style="color:#222222">(</span><span style="color:#0468D7">Icons</span><span style="color:#222222">.message),</span></span> <span class="line"><span style="color:#0468D7"> Expanded</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> child: </span><span style="color:#0468D7">Column</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#6E6E70"> // code omitted</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ],</span></span> <span class="line"><span style="color:#222222">);</span></span></code></pre></div></div><p>Another way is to wrap the <code>Column</code> in a <code>Flexible</code> widget and specify a <code>flex</code> factor. In fact, the <code>Expanded</code> widget is equivalent to the <code>Flexible</code> widget with a <code>flex</code> factor of 1.0, as <a href="https://github.com/flutter/flutter/blob/c8e42b47f5ea8b5ff7bf2f2b0a2a8e765f1aa51d/packages/flutter/lib/src/widgets/basic.dart#L5166-L5174">its source code</a> shows. To further understand how to use the <code>Flex</code> widget in Flutter layouts, check out <a href="https://www.youtube.com/watch?v=CI7x0mAZiY0">this 90-second Widget of the Week video</a> on the <code>Flexible</code> widget.</p><p><strong>Further information:</strong></p><p>The resources linked below provide further information about this error.</p><ul><li><a href="https://www.youtube.com/watch?v=CI7x0mAZiY0">Flexible (Flutter Widget of the Week)</a></li><li><a href="https://medium.com/flutter/how-to-debug-layout-issues-with-the-flutter-inspector-87460a7b9db#738b">How to debug layout issues with the Flutter Inspector</a></li><li><a href="/ui/layout/constraints">Understanding constraints</a></li></ul><div class="header-wrapper"><h2 id="renderbox-was-not-laid-out">'RenderBox was not laid out'</h2><a class="heading-link" href="#renderbox-was-not-laid-out" aria-label="Link to ''RenderBox was not laid out'' section">#</a></div><p>While this error is pretty common, it's often a side effect of a primary error occurring earlier in the rendering pipeline.</p><p><strong>What does the error look like?</strong></p><p>The message shown by the error looks like this:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>RenderBox was not laid out: </span></span> <span class="line"><span>RenderViewport#5a477 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE</span></span></code></pre></div></div><p><strong>How might you run into this error?</strong></p><p>Usually, the issue is related to violation of box constraints, and it needs to be solved by providing more information to Flutter about how you'd like to constrain the widgets in question. You can learn more about how constraints work in Flutter on the <a href="/ui/layout/constraints">Understanding constraints</a> page.</p><p>The <code>RenderBox was not laid out</code> error is often caused by one of two other errors:</p><ul><li>'Vertical viewport was given unbounded height'</li><li>'An InputDecorator...cannot have an unbounded width'</li></ul><p><a id="unbounded"></a></p><div class="header-wrapper"><h2 id="vertical-viewport-was-given-unbounded-height">'Vertical viewport was given unbounded height'</h2><a class="heading-link" href="#vertical-viewport-was-given-unbounded-height" aria-label="Link to ''Vertical viewport was given unbounded height'' section">#</a></div><p>This is another common layout error you could run into while creating a UI in your Flutter app.</p><p><strong>What does the error look like?</strong></p><p>The message shown by the error looks like this:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>The following assertion was thrown during performResize():</span></span> <span class="line"><span>Vertical viewport was given unbounded height.</span></span> <span class="line"><span></span></span> <span class="line"><span>Viewports expand in the scrolling direction to fill their container. </span></span> <span class="line"><span>In this case, a vertical viewport was given an unlimited amount of </span></span> <span class="line"><span>vertical space in which to expand. This situation typically happens when a </span></span> <span class="line"><span>scrollable widget is nested inside another scrollable widget.</span></span> <span class="line"><span>(Additional lines of this message omitted)</span></span></code></pre></div></div><p><strong>How might you run into this error?</strong></p><p>The error is often caused when a <code>ListView</code> (or other kinds of scrollable widgets such as <code>GridView</code>) is placed inside a <code>Column</code>. A <code>ListView</code> takes all the vertical space available to it, unless it's constrained by its parent widget. However, a <code>Column</code> doesn't impose any constraint on its children's height by default. The combination of the two behaviors leads to the failure of determining the size of the <code>ListView</code>.</p> <?code-excerpt "lib/unbounded_height.dart (problem)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#0468D7">Widget</span><span style="color:#6200EE"> build</span><span style="color:#222222">(</span><span style="color:#0468D7">BuildContext</span><span style="color:#222222"> context) {</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#0468D7"> Center</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> child: </span><span style="color:#0468D7">Column</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> children: <</span><span style="color:#0468D7">Widget</span><span style="color:#222222">>[</span></span> <span class="line"><span style="color:#BD2314"> const</span><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Header'</span><span style="color:#222222">),</span></span> <span class="line"><span style="color:#0468D7"> ListView</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> children: </span><span style="color:#BD2314">const</span><span style="color:#222222"> <</span><span style="color:#0468D7">Widget</span><span style="color:#222222">>[</span></span> <span class="line"><span style="color:#0468D7"> ListTile</span><span style="color:#222222">(leading: </span><span style="color:#0468D7">Icon</span><span style="color:#222222">(</span><span style="color:#0468D7">Icons</span><span style="color:#222222">.map), title: </span><span style="color:#0468D7">Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Map'</span><span style="color:#222222">)),</span></span> <span class="line"><span style="color:#0468D7"> ListTile</span><span style="color:#222222">(leading: </span><span style="color:#0468D7">Icon</span><span style="color:#222222">(</span><span style="color:#0468D7">Icons</span><span style="color:#222222">.subway), title: </span><span style="color:#0468D7">Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Subway'</span><span style="color:#222222">)),</span></span> <span class="line"><span style="color:#222222"> ],</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ],</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p><strong>How to fix it?</strong></p><p>To fix this error, specify how tall the <code>ListView</code> should be. To make it as tall as the remaining space in the <code>Column</code>, wrap it using an <code>Expanded</code> widget (as shown in the following example). Otherwise, specify an absolute height using a <code>SizedBox</code> widget or a relative height using a <code>Flexible</code> widget.</p> <?code-excerpt "lib/unbounded_height.dart (solution)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#0468D7">Widget</span><span style="color:#6200EE"> build</span><span style="color:#222222">(</span><span style="color:#0468D7">BuildContext</span><span style="color:#222222"> context) {</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#0468D7"> Center</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> child: </span><span style="color:#0468D7">Column</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> children: <</span><span style="color:#0468D7">Widget</span><span style="color:#222222">>[</span></span> <span class="line"><span style="color:#BD2314"> const</span><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Header'</span><span style="color:#222222">),</span></span> <span class="line"><span style="color:#0468D7"> Expanded</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> child: </span><span style="color:#0468D7">ListView</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> children: </span><span style="color:#BD2314">const</span><span style="color:#222222"> <</span><span style="color:#0468D7">Widget</span><span style="color:#222222">>[</span></span> <span class="line"><span style="color:#0468D7"> ListTile</span><span style="color:#222222">(leading: </span><span style="color:#0468D7">Icon</span><span style="color:#222222">(</span><span style="color:#0468D7">Icons</span><span style="color:#222222">.map), title: </span><span style="color:#0468D7">Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Map'</span><span style="color:#222222">)),</span></span> <span class="line"><span style="color:#0468D7"> ListTile</span><span style="color:#222222">(leading: </span><span style="color:#0468D7">Icon</span><span style="color:#222222">(</span><span style="color:#0468D7">Icons</span><span style="color:#222222">.subway), title: </span><span style="color:#0468D7">Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Subway'</span><span style="color:#222222">)),</span></span> <span class="line"><span style="color:#222222"> ],</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ],</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p><strong>Further information:</strong></p><p>The resources linked below provide further information about this error.</p><ul><li><a href="https://medium.com/flutter/how-to-debug-layout-issues-with-the-flutter-inspector-87460a7b9db#738b">How to debug layout issues with the Flutter Inspector</a></li><li><a href="/ui/layout/constraints">Understanding constraints</a></li></ul><div class="header-wrapper"><h2 id="an-inputdecorator-cannot-have-an-unbounded-width">'An InputDecorator...cannot have an unbounded width'</h2><a class="heading-link" href="#an-inputdecorator-cannot-have-an-unbounded-width" aria-label="Link to ''An InputDecorator...cannot have an unbounded width'' section">#</a></div><p>The error message suggests that it's also related to box constraints, which are important to understand to avoid many of the most common Flutter framework errors.</p><p><strong>What does the error look like?</strong></p><p>The message shown by the error looks like this:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>The following assertion was thrown during performLayout():</span></span> <span class="line"><span>An InputDecorator, which is typically created by a TextField, cannot have an </span></span> <span class="line"><span>unbounded width.</span></span> <span class="line"><span>This happens when the parent widget does not provide a finite width constraint. </span></span> <span class="line"><span>For example, if the InputDecorator is contained by a `Row`, then its width must </span></span> <span class="line"><span>be constrained. An `Expanded` widget or a SizedBox can be used to constrain the </span></span> <span class="line"><span>width of the InputDecorator or the TextField that contains it.</span></span> <span class="line"><span>(Additional lines of this message omitted)</span></span></code></pre></div></div><p><strong>How might you run into the error?</strong></p><p>This error occurs, for example, when a <code>Row</code> contains a <code>TextFormField</code> or a <code>TextField</code> but the latter has no width constraint.</p> <?code-excerpt "lib/unbounded_width.dart (problem)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#0468D7">Widget</span><span style="color:#6200EE"> build</span><span style="color:#222222">(</span><span style="color:#0468D7">BuildContext</span><span style="color:#222222"> context) {</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#0468D7"> MaterialApp</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> home: </span><span style="color:#0468D7">Scaffold</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> appBar: </span><span style="color:#0468D7">AppBar</span><span style="color:#222222">(title: </span><span style="color:#BD2314">const</span><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Unbounded Width of the TextField'</span><span style="color:#222222">)),</span></span> <span class="line"><span style="color:#222222"> body: </span><span style="color:#BD2314">const</span><span style="color:#0468D7"> Row</span><span style="color:#222222">(children: [</span><span style="color:#0468D7">TextField</span><span style="color:#222222">()]),</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p><strong>How to fix it?</strong></p><p>As suggested by the error message, fix this error by constraining the text field using either an <code>Expanded</code> or <code>SizedBox</code> widget. The following example demonstrates using an <code>Expanded</code> widget:</p> <?code-excerpt "lib/unbounded_width.dart (solution)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#0468D7">Widget</span><span style="color:#6200EE"> build</span><span style="color:#222222">(</span><span style="color:#0468D7">BuildContext</span><span style="color:#222222"> context) {</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#0468D7"> MaterialApp</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> home: </span><span style="color:#0468D7">Scaffold</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> appBar: </span><span style="color:#0468D7">AppBar</span><span style="color:#222222">(title: </span><span style="color:#BD2314">const</span><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Unbounded Width of the TextField'</span><span style="color:#222222">)),</span></span> <span class="line"><span style="color:#222222"> body: </span><span style="color:#0468D7">Row</span><span style="color:#222222">(children: [</span><span style="color:#0468D7">Expanded</span><span style="color:#222222">(child: </span><span style="color:#0468D7">TextFormField</span><span style="color:#222222">())]),</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><div class="header-wrapper"><h2 id="incorrect-use-of-parentdata-widget">'Incorrect use of ParentData widget'</h2><a class="heading-link" href="#incorrect-use-of-parentdata-widget" aria-label="Link to ''Incorrect use of ParentData widget'' section">#</a></div><p>This error is about missing an expected parent widget.</p><p><strong>What does the error look like?</strong></p><p>The message shown by the error looks like this:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>The following assertion was thrown while looking for parent data:</span></span> <span class="line"><span>Incorrect use of ParentDataWidget.</span></span> <span class="line"><span>(Some lines of this message omitted)</span></span> <span class="line"><span>Usually, this indicates that at least one of the offending ParentDataWidgets </span></span> <span class="line"><span>listed above is not placed directly inside a compatible ancestor widget.</span></span></code></pre></div></div><p><strong>How might you run into the error?</strong></p><p>While Flutter's widgets are generally flexible in how they can be composed together in a UI, a small subset of those widgets expect specific parent widgets. When this expectation can't be satisfied in your widget tree, you're likely to encounter this error.</p><p>Here is an <em>incomplete</em> list of widgets that expect specific parent widgets within the Flutter framework. Feel free to submit a PR (using the doc icon in the top right corner of the page) to expand this list.</p><div class="table-wrapper"><table><thead><tr><th style="text-align:left">Widget</th><th style="text-align:right">Expected parent widget(s)</th></tr></thead><tbody><tr><td style="text-align:left"><code>Flexible</code></td><td style="text-align:right"><code>Row</code>, <code>Column</code>, or <code>Flex</code></td></tr><tr><td style="text-align:left"><code>Expanded</code> (a specialized <code>Flexible</code>)</td><td style="text-align:right"><code>Row</code>, <code>Column</code>, or <code>Flex</code></td></tr><tr><td style="text-align:left"><code>Positioned</code></td><td style="text-align:right"><code>Stack</code></td></tr><tr><td style="text-align:left"><code>TableCell</code></td><td style="text-align:right"><code>Table</code></td></tr></tbody></table></div><p><strong>How to fix it?</strong></p><p>The fix should be obvious once you know which parent widget is missing.</p><div class="header-wrapper"><h2 id="setstate-called-during-build">'setState called during build'</h2><a class="heading-link" href="#setstate-called-during-build" aria-label="Link to ''setState called during build'' section">#</a></div><p>The <code>build</code> method in your Flutter code isn't a good place to call <code>setState</code>, either directly or indirectly.</p><p><strong>What does the error look like?</strong></p><p>When the error occurs, the following message is displayed in the console:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>The following assertion was thrown building DialogPage(dirty, dependencies: </span></span> <span class="line"><span>[_InheritedTheme, _LocalizationsScope-[GlobalKey#59a8e]], </span></span> <span class="line"><span>state: _DialogPageState#f121e):</span></span> <span class="line"><span>setState() or markNeedsBuild() called during build.</span></span> <span class="line"><span></span></span> <span class="line"><span>This Overlay widget cannot be marked as needing to build because the framework </span></span> <span class="line"><span>is already in the process of building widgets.</span></span> <span class="line"><span>(Additional lines of this message omitted)</span></span></code></pre></div></div><p><strong>How might you run into the error?</strong></p><p>In general, this error occurs when the <code>setState</code> method is called within the <code>build</code> method.</p><p>A common scenario where this error occurs is when attempting to trigger a <code>Dialog</code> from within the <code>build</code> method. This is often motivated by the need to immediately show information to the user, but <code>setState</code> should never be called from a <code>build</code> method.</p><p>The following snippet seems to be a common culprit of this error:</p> <?code-excerpt "lib/set_state_build.dart (problem)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#0468D7">Widget</span><span style="color:#6200EE"> build</span><span style="color:#222222">(</span><span style="color:#0468D7">BuildContext</span><span style="color:#222222"> context) {</span></span> <span class="line"><span style="color:#6E6E70"> // Don't do this.</span></span> <span class="line"><span style="color:#6200EE"> showDialog</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> context: context,</span></span> <span class="line"><span style="color:#222222"> builder: (context) {</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#BD2314"> const</span><span style="color:#0468D7"> AlertDialog</span><span style="color:#222222">(title: </span><span style="color:#0468D7">Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Alert Dialog'</span><span style="color:#222222">));</span></span> <span class="line"><span style="color:#222222"> },</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#BD2314"> const</span><span style="color:#0468D7"> Center</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> child: </span><span style="color:#0468D7">Column</span><span style="color:#222222">(children: <</span><span style="color:#0468D7">Widget</span><span style="color:#222222">>[</span><span style="color:#0468D7">Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Show Material Dialog'</span><span style="color:#222222">)]),</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>This code doesn't make an explicit call to <code>setState</code>, but it's called by <code>showDialog</code>. The <code>build</code> method isn't the right place to call <code>showDialog</code> because <code>build</code> can be called by the framework for every frame, for example, during an animation.</p><p><strong>How to fix it?</strong></p><p>One way to avoid this error is to use the <code>Navigator</code> API to trigger the dialog as a route. In the following example, there are two pages. The second page has a dialog to be displayed upon entry. When the user requests the second page by clicking a button on the first page, the <code>Navigator</code> pushes two routes–one for the second page and another for the dialog.</p> <?code-excerpt "lib/set_state_build.dart (solution)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#BD2314">class</span><span style="color:#0468D7"> FirstScreen</span><span style="color:#BD2314"> extends</span><span style="color:#0468D7"> StatelessWidget</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#BD2314"> const</span><span style="color:#0468D7"> FirstScreen</span><span style="color:#222222">({</span><span style="color:#BD2314">super</span><span style="color:#222222">.key});</span></span> <span class="line"></span> <span class="line"><span style="color:#BD2314"> @override</span></span> <span class="line"><span style="color:#0468D7"> Widget</span><span style="color:#6200EE"> build</span><span style="color:#222222">(</span><span style="color:#0468D7">BuildContext</span><span style="color:#222222"> context) {</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#0468D7"> Scaffold</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> appBar: </span><span style="color:#0468D7">AppBar</span><span style="color:#222222">(title: </span><span style="color:#BD2314">const</span><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'First Screen'</span><span style="color:#222222">)),</span></span> <span class="line"><span style="color:#222222"> body: </span><span style="color:#0468D7">Center</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> child: </span><span style="color:#0468D7">ElevatedButton</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> child: </span><span style="color:#BD2314">const</span><span style="color:#0468D7"> Text</span><span style="color:#222222">(</span><span style="color:#0C7064">'Launch screen'</span><span style="color:#222222">),</span></span> <span class="line"><span style="color:#222222"> onPressed: () {</span></span> <span class="line"><span style="color:#6E6E70"> // Navigate to the second screen using a named route.</span></span> <span class="line"><span style="color:#0468D7"> Navigator</span><span style="color:#222222">.</span><span style="color:#6200EE">pushNamed</span><span style="color:#222222">(context, </span><span style="color:#0C7064">'/second'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#6E6E70"> // Immediately show a dialog upon loading the second screen.</span></span> <span class="line"><span style="color:#0468D7"> Navigator</span><span style="color:#222222">.</span><span style="color:#6200EE">push</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> context,</span></span> <span class="line"><span style="color:#0468D7"> PageRouteBuilder</span><span style="color:#222222">(</span></span> <span class="line"><span style="color:#222222"> barrierDismissible: </span><span style="color:#0C7064">true</span><span style="color:#222222">,</span></span> <span class="line"><span style="color:#222222"> opaque: </span><span style="color:#0C7064">false</span><span style="color:#222222">,</span></span> <span class="line"><span style="color:#222222"> pageBuilder: (_, anim1, anim2) => </span><span style="color:#BD2314">const</span><span style="color:#0468D7"> MyDialog</span><span style="color:#222222">(),</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222"> },</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> ),</span></span> <span class="line"><span style="color:#222222"> );</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><div class="header-wrapper"><h2 id="the-scrollcontroller-is-attached-to-multiple-scroll-views"><code>The ScrollController is attached to multiple scroll views</code></h2><a class="heading-link" href="#the-scrollcontroller-is-attached-to-multiple-scroll-views" aria-label="Link to 'The ScrollController is attached to multiple scroll views' section">#</a></div><p>This error can occur when multiple scrolling widgets (such as <code>ListView</code>) appear on the screen at the same time. It's more likely for this error to occur on a web or desktop app, than a mobile app since it's rare to encounter this scenario on mobile.</p><p>For more information and to learn how to fix, check out the following video on <a href="https://api.flutter.dev/flutter/widgets/PrimaryScrollController-class.html"><code>PrimaryScrollController</code></a>:</p><iframe width="560" height="315" src="https://www.youtube.com/embed/33_0ABjFJUU" title="PrimaryScrollController | Decoding Flutter" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen loading="lazy"></iframe><br><div class="header-wrapper"><h2 id="references">References</h2><a class="heading-link" href="#references" aria-label="Link to 'References' section">#</a></div><p>To learn more about how to debug errors, especially layout errors in Flutter, check out the following resources:</p><ul><li><a href="https://medium.com/flutter/how-to-debug-layout-issues-with-the-flutter-inspector-87460a7b9db#738b">How to debug layout issues with the Flutter Inspector</a></li><li><a href="/ui/layout/constraints">Understanding constraints</a></li><li><a href="/resources/architectural-overview#layout-and-rendering">Flutter architectural overview</a></li></ul><p id="page-github-links"><span>Unless stated otherwise, the documentation on this site reflects the latest stable version of Flutter. Page last updated on 2025-02-12.</span> <a href="https://github.com/flutter/website/tree/main/src/content/testing/common-errors.md" target="_blank" rel="noopener">View source</a> <span>or </span><a href="https://github.com/flutter/website/issues/new?template=1_page_issue.yml&&page-url=https://docs.flutter.dev/testing/common-errors/&page-source=https://github.com/flutter/website/tree/main/src/content/testing/common-errors.md" title="Report an issue with this page" target="_blank" rel="noopener">report an issue</a>.</p></article></main></div><footer id="site-footer"><div class="footer-section footer-main"><a class="brand" href="https://flutter.dev"><img src="/assets/images/branding/flutter/logo+text/horizontal/white.svg" alt="Flutter logo" width="164"></a><div class="footer-social-links"><a class="icon-button" href="https://medium.com/flutter" target="_blank" rel="noopener" title="Flutter's Medium blog"><svg><use href="/assets/images/social/medium.svg#medium"></use></svg> </a><a class="icon-button" href="https://youtube.com/@flutterdev" target="_blank" rel="noopener" title="Flutter's YouTube"><svg><use href="/assets/images/social/youtube.svg#youtube"></use></svg> </a><a class="icon-button" href="https://github.com/flutter" target="_blank" rel="noopener" title="Flutter's GitHub"><svg><use href="/assets/images/social/github.svg#github"></use></svg> </a><a class="icon-button" href="https://bsky.app/profile/flutter.dev" target="_blank" rel="noopener" title="Flutter's Bluesky"><svg><use href="/assets/images/social/bluesky.svg#bluesky"></use></svg> </a><a class="icon-button" href="https://twitter.com/FlutterDev" target="_blank" rel="noopener" title="Flutter's X (Twitter)"><svg><use href="/assets/images/social/x.svg#x"></use></svg></a></div></div><div class="footer-section footer-tray"><div class="footer-licenses">Except as otherwise noted, this site is licensed under a <a href="https://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>, and code samples are licensed under the <a href="https://opensource.org/licenses/BSD-3-Clause">3-Clause BSD License</a>.</div><div class="footer-utility-links"><ul><li><a href="/tos" title="Terms of use">Terms</a></li><li><a href="/brand" title="Brand usage guidelines">Brand</a></li><li><a href="https://policies.google.com/privacy" target="_blank" rel="noopener" title="Privacy policy">Privacy</a></li><li><a href="/security" title="Security philosophy and practices">Security</a></li></ul></div></div></footer></div><script src="/assets/js/tabs.js?v=4"></script><script src="/assets/js/archive.js?v=4"></script><script src="/assets/js/main.js?v=4"></script></body></html>