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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 collapsed collapsible" data-toggle="collapse" data-target="#sidenav-24" role="button" aria-expanded="false" aria-controls="sidenav-24"><span>Testing & debugging</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse" 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" 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 active collapsible" data-toggle="collapse" data-target="#sidenav-25" role="button" aria-expanded="true" aria-controls="sidenav-25"><span>Performance & optimization</span> <span class="material-symbols expander" aria-hidden="true">expand_more</span></button><ul class="nav collapse show" 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 active" 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" 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href="#message-passing-between-isolates">Message passing between isolates</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#short-lived-isolates">Short-lived isolates</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#stateful-longer-lived-isolates">Stateful, longer-lived isolates</a><ul class="nav"><li class="toc-entry nav-item"><a class="nav-link" href="#receiveports-and-sendports">ReceivePorts and SendPorts</a></li></ul></li><li class="toc-entry nav-item"><a class="nav-link" href="#using-platform-plugins-in-isolates">Using platform plugins in isolates</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#limitations-of-isolates">Limitations of Isolates</a><ul class="nav"><li class="toc-entry nav-item"><a class="nav-link" href="#web-platforms-and-compute">Web platforms and compute</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#no-rootbundle-access-or-dart-ui-methods">No rootBundle access or dart:ui methods</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#limited-plugin-messages-from-host-platform-to-flutter">Limited plugin messages from host platform to Flutter</a></li></ul></li><li class="toc-entry nav-item"><a class="nav-link" href="#more-information">More information</a></li></ul></div><article><header class="site-content__title"><h1 id="document-title">Concurrency and isolates</h1><nav class="breadcrumbs" aria-label="breadcrumb"><ol vocab="https://schema.org/" typeof="BreadcrumbList"><li class="breadcrumb-item" property="itemListElement" typeof="ListItem"><a href="/perf" property="item" typeof="WebPage"><span property="name">Performance</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="/perf/isolates" property="item" typeof="WebPage"><span property="name">Concurrency and isolates</span></a><meta property="position" content="1"></li></ol></nav></header><div id="site-toc--inline" class="site-toc toc-collapsible toc-collapsed"><header class="site-toc__title">Contents <span class="site-toc--inline__toggle toc-toggle-down" title="Expand table of contents"><i class="material-symbols" aria-hidden="true">keyboard_arrow_down</i></span> <span class="site-toc--inline__toggle toc-toggle-up" title="Collapse table of contents"><i class="material-symbols" aria-hidden="true">keyboard_arrow_up</i></span></header><ul class="section-nav"><li class="toc-entry"><a href="#common-use-cases-for-isolates">Common use cases for isolates</a></li><li class="toc-entry"><a href="#message-passing-between-isolates">Message passing between isolates</a></li><li class="toc-entry"><a href="#short-lived-isolates">Short-lived isolates</a></li><li class="toc-entry"><a href="#stateful-longer-lived-isolates">Stateful, longer-lived isolates</a><ul><li class="toc-entry"><a href="#receiveports-and-sendports">ReceivePorts and SendPorts</a></li></ul></li><li class="toc-entry"><a href="#using-platform-plugins-in-isolates">Using platform plugins in isolates</a></li><li class="toc-entry"><a href="#limitations-of-isolates">Limitations of Isolates</a><ul><li class="toc-entry"><a href="#web-platforms-and-compute">Web platforms and compute</a></li><li class="toc-entry"><a href="#no-rootbundle-access-or-dart-ui-methods">No rootBundle access or dart:ui methods</a></li><li class="toc-entry"><a href="#limited-plugin-messages-from-host-platform-to-flutter">Limited plugin messages from host platform to Flutter</a></li></ul></li><li class="toc-entry"><a href="#more-information">More information</a></li></ul><span class="site-toc--inline__toggle toc-toggle-more-items" title="Expand table of contents"><i class="material-symbols" aria-hidden="true">more_horiz</i></span></div> <?code-excerpt path-base="perf/concurrency/isolates/"?> <p>All Dart code runs in <a href="https://dart.dev/language/concurrency">isolates</a>, which are similar to threads, but differ in that isolates have their own isolated memory. They do not share state in any way, and can only communicate by messaging. By default, Flutter apps do all of their work on a single isolate – the main isolate. In most cases, this model allows for simpler programming and is fast enough that the application's UI doesn't become unresponsive.</p><p>Sometimes though, applications need to perform exceptionally large computations that can cause "UI jank" (jerky motion). If your app is experiencing jank for this reason, you can move these computations to a helper isolate. This allows the underlying runtime environment to run the computation concurrently with the main UI isolate's work and takes advantage of multi-core devices.</p><p>Each isolate has its own memory and its own event loop. The event loop processes events in the order that they're added to an event queue. On the main isolate, these events can be anything from handling a user tapping in the UI, to executing a function, to painting a frame on the screen. The following figure shows an example event queue with 3 events waiting to be processed.</p><p><img src="/assets/images/docs/development/concurrency/basics-main-isolate.png" alt="The main isolate diagram" width="50%"></p><p>For smooth rendering, Flutter adds a "paint frame" event to the event queue 60 times per second(for a 60Hz device). If these events aren't processed on time, the application experiences UI jank, or worse, become unresponsive altogether.</p><p><img src="/assets/images/docs/development/concurrency/event-jank.png" alt="Event jank diagram" width="50%"></p><p>Whenever a process can't be completed in a frame gap, the time between two frames, it's a good idea to offload the work to another isolate to ensure that the main isolate can produce 60 frames per second. When you spawn an isolate in Dart, it can process the work concurrently with the main isolate, without blocking it.</p><p>You can read more about how isolates and the event loop work in Dart on the <a href="https://dart.dev/language/concurrency">concurrency page</a> of the Dart documentation.</p><iframe width="560" height="315" src="https://www.youtube.com/embed/vl_AaCgudcY" title="Isolates and the event loop | Flutter in Focus" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen loading="lazy"></iframe><br><p><a href="https://www.youtube.com/watch/vl_AaCgudcY" target="_blank" rel="noopener" title="Open 'Isolates and the event loop | Flutter in Focus' video in new tab">Isolates and the event loop | Flutter in Focus</a></p><div class="header-wrapper"><h2 id="common-use-cases-for-isolates">Common use cases for isolates</h2><a class="heading-link" href="#common-use-cases-for-isolates" aria-label="Link to 'Common use cases for isolates' section">#</a></div><p>There is only one hard rule for when you should use isolates, and that's when large computations are causing your Flutter application to experience UI jank. This jank happens when there is any computation that takes longer than Flutter's frame gap.</p><p><img src="/assets/images/docs/development/concurrency/event-jank.png" alt="Event jank diagram" width="50%"></p><p>Any process <em>could</em> take longer to complete, depending on the implementation and the input data, making it impossible to create an exhaustive list of when you need to consider using isolates.</p><p>That said, isolates are commonly used for the following:</p><ul><li>Reading data from a local database</li><li>Sending push notifications</li><li>Parsing and decoding large data files</li><li>Processing or compressing photos, audio files, and video files</li><li>Converting audio and video files</li><li>When you need asynchronous support while using FFI</li><li>Applying filtering to complex lists or filesystems</li></ul><div class="header-wrapper"><h2 id="message-passing-between-isolates">Message passing between isolates</h2><a class="heading-link" href="#message-passing-between-isolates" aria-label="Link to 'Message passing between isolates' section">#</a></div><p>Dart's isolates are an implementation of the <a href="https://en.wikipedia.org/wiki/Actor_model">Actor model</a>. They can only communicate with each other by message passing, which is done with <a href="https://api.dart.dev/dart-isolate/ReceivePort-class.html"><code>Port</code> objects</a>. When messages are "passed" between each other, they are generally copied from the sending isolate to the receiving isolate. This means that any value passed to an isolate, even if mutated on that isolate, doesn't change the value on the original isolate.</p><p>The only <a href="https://api.dart.dev/dart-isolate/SendPort/send.html">objects that aren't copied when passed</a> to an isolate are immutable objects that can't be changed anyway, such a String or an unmodifiable byte. When you pass an immutable object between isolates, a reference to that object is sent across the port, rather than the object being copied, for better performance. Because immutable objects can't be updated, this effectively retains the actor model behavior.</p><p>An exception to this rule is when an isolate exits when it sends a message using the <code>Isolate.exit</code> method. Because the sending isolate won't exist after sending the message, it can pass ownership of the message from one isolate to the other, ensuring that only one isolate can access the message.</p><p>The two lowest-level primitives that send messages are <code>SendPort.send</code>, which makes a copy of a mutable message as it sends, and <code>Isolate.exit</code>, which sends the reference to the message. Both <code>Isolate.run</code> and <code>compute</code> use <code>Isolate.exit</code> under the hood.</p><div class="header-wrapper"><h2 id="short-lived-isolates">Short-lived isolates</h2><a class="heading-link" href="#short-lived-isolates" aria-label="Link to 'Short-lived isolates' section">#</a></div><p>The easiest way to move a process to an isolate in Flutter is with the <code>Isolate.run</code> method. This method spawns an isolate, passes a callback to the spawned isolate to start some computation, returns a value from the computation, and then shuts the isolate down when the computation is complete. This all happens concurrently with the main isolate, and doesn't block it.</p><p><img src="/assets/images/docs/development/concurrency/isolate-bg-worker.png" alt="Isolate diagram" width="50%"></p><p>The <code>Isolate.run</code> method requires a single argument, a callback function, that is run on the new isolate. This callback's function signature must have exactly one required, unnamed argument. When the computation completes, it returns the callback's value back to the main isolate, and exits the spawned isolate.</p><p>For example, consider this code that loads a large JSON blob from a file, and converts that JSON into custom Dart objects. If the json decoding process wasn't off loaded to a new isolate, this method would cause the UI to become unresponsive for several seconds.</p> <?code-excerpt "lib/main.dart (isolate-run)"?> <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:#6E6E70">// Produces a list of 211,640 photo objects.</span></span> <span class="line"><span style="color:#6E6E70">// (The JSON file is ~20MB.)</span></span> <span class="line"><span style="color:#0468D7">Future</span><span style="color:#222222"><</span><span style="color:#0468D7">List</span><span style="color:#222222"><</span><span style="color:#0468D7">Photo</span><span style="color:#222222">>> </span><span style="color:#6200EE">getPhotos</span><span style="color:#222222">() </span><span style="color:#BD2314">async</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#BD2314"> final</span><span style="color:#0468D7"> String</span><span style="color:#222222"> jsonString = </span><span style="color:#BD2314">await</span><span style="color:#222222"> rootBundle.</span><span style="color:#6200EE">loadString</span><span style="color:#222222">(</span><span style="color:#0C7064">'assets/photos.json'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#BD2314"> final</span><span style="color:#0468D7"> List</span><span style="color:#222222"><</span><span style="color:#0468D7">Photo</span><span style="color:#222222">> photos = </span><span style="color:#BD2314">await</span><span style="color:#0468D7"> Isolate</span><span style="color:#222222">.</span><span style="color:#6200EE">run</span><span style="color:#222222"><</span><span style="color:#0468D7">List</span><span style="color:#222222"><</span><span style="color:#0468D7">Photo</span><span style="color:#222222">>>(() {</span></span> <span class="line"><span style="color:#BD2314"> final</span><span style="color:#0468D7"> List</span><span style="color:#222222"><</span><span style="color:#0468D7">Object</span><span style="color:#222222">?> photoData = </span><span style="color:#6200EE">jsonDecode</span><span style="color:#222222">(jsonString) </span><span style="color:#BD2314">as</span><span style="color:#0468D7"> List</span><span style="color:#222222"><</span><span style="color:#0468D7">Object</span><span style="color:#222222">?>;</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#222222"> photoData.</span><span style="color:#6200EE">cast</span><span style="color:#222222"><</span><span style="color:#0468D7">Map</span><span style="color:#222222"><</span><span style="color:#0468D7">String</span><span style="color:#222222">, </span><span style="color:#0468D7">Object</span><span style="color:#222222">?>>().</span><span style="color:#6200EE">map</span><span style="color:#222222">(</span><span style="color:#0468D7">Photo</span><span style="color:#222222">.fromJson).</span><span style="color:#6200EE">toList</span><span style="color:#222222">();</span></span> <span class="line"><span style="color:#222222"> });</span></span> <span class="line"><span style="color:#BD2314"> return</span><span style="color:#222222"> photos;</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>For a complete walkthrough of using Isolates to parse JSON in the background, see <a href="/cookbook/networking/background-parsing">this cookbook recipe</a>.</p><div class="header-wrapper"><h2 id="stateful-longer-lived-isolates">Stateful, longer-lived isolates</h2><a class="heading-link" href="#stateful-longer-lived-isolates" aria-label="Link to 'Stateful, longer-lived isolates' section">#</a></div><p>Short-live isolates are convenient to use, but there is performance overhead required to spawn new isolates, and to copy objects from one isolate to another. If you're doing the same computation using <code>Isolate.run</code> repeatedly, you might have better performance by creating isolates that don't exit immediately.</p><p>To do this, you can use a handful of lower-level isolate-related APIs that <code>Isolate.run</code> abstracts:</p><ul><li><a href="https://api.dart.dev/dart-isolate/Isolate/spawn.html"><code>Isolate.spawn()</code></a> and <a href="https://api.dart.dev/dart-isolate/Isolate/exit.html"><code>Isolate.exit()</code></a></li><li><a href="https://api.dart.dev/dart-isolate/ReceivePort-class.html"><code>ReceivePort</code></a> and <a href="https://api.dart.dev/dart-isolate/SendPort-class.html"><code>SendPort</code></a></li><li><a href="https://api.dart.dev/dart-isolate/SendPort/send.html"><code>send()</code></a> method</li></ul><p>When you use the <code>Isolate.run</code> method, the new isolate immediately shuts down after it returns a single message to the main isolate. Sometimes, you'll need isolates that are long lived, and can pass multiple messages to each other over time. In Dart, you can accomplish this with the Isolate API and Ports. These long-lived isolates are colloquially known as <em>background workers</em>.</p><p>Long-lived isolates are useful when you have a specific process that either needs to be run repeatedly throughout the lifetime of your application, or if you have a process that runs over a period of time and needs to yield multiple return values to the main isolate.</p><p>Or, you might use <a href="https://pub.dev/packages/worker_manager">worker_manager</a> to manage long-lived isolates.</p><div class="header-wrapper"><h3 id="receiveports-and-sendports">ReceivePorts and SendPorts</h3><a class="heading-link" href="#receiveports-and-sendports" aria-label="Link to 'ReceivePorts and SendPorts' section">#</a></div><p>Set up long-lived communication between isolates with two classes (in addition to Isolate): <a href="https://api.dart.dev/dart-isolate/ReceivePort-class.html"><code>ReceivePort</code></a> and <a href="https://api.dart.dev/dart-isolate/SendPort-class.html"><code>SendPort</code></a>. These ports are the only way isolates can communicate with each other.</p><p><code>Ports</code> behave similarly to <code>Streams</code>, in which the <code>StreamController</code> or <code>Sink</code> is created in one isolate, and the listener is set up in the other isolate. In this analogy, the <code>StreamConroller</code> is called a <code>SendPort</code>, and you can "add" messages with the <code>send()</code> method. <code>ReceivePort</code>s are the listeners, and when these listeners receive a new message, they call a provided callback with the message as an argument.</p><p>For an in-depth explanation on setting up two-way communication between the main isolate and a worker isolate, follow the examples in the <a href="https://dart.dev/language/concurrency">Dart documentation</a>.</p><div class="header-wrapper"><h2 id="using-platform-plugins-in-isolates">Using platform plugins in isolates</h2><a class="heading-link" href="#using-platform-plugins-in-isolates" aria-label="Link to 'Using platform plugins in isolates' section">#</a></div><p>As of Flutter 3.7, you can use platform plugins in background isolates. This opens many possibilities to offload heavy, platform-dependent computations to an isolate that won't block your UI. For example, imagine you're encrypting data using a native host API (such as an Android API on Android, an iOS API on iOS, and so on). Previously, <a href="https://en.wikipedia.org/wiki/Marshalling_(computer_science)">marshaling data</a> to the host platform could waste UI thread time, and can now be done in a background isolate.</p><p>Platform channel isolates use the <a href="https://api.flutter.dev/flutter/services/BackgroundIsolateBinaryMessenger-class.html"><code>BackgroundIsolateBinaryMessenger</code></a> API. The following snippet shows an example of using the <code>shared_preferences</code> package in a background isolate.</p> <?code-excerpt "lib/isolate_binary_messenger.dart"?> <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">import</span><span style="color:#0C7064"> 'dart:isolate'</span><span style="color:#222222">;</span></span> <span class="line"></span> <span class="line"><span style="color:#BD2314">import</span><span style="color:#0C7064"> 'package:flutter/services.dart'</span><span style="color:#222222">;</span></span> <span class="line"><span style="color:#BD2314">import</span><span style="color:#0C7064"> 'package:shared_preferences/shared_preferences.dart'</span><span style="color:#222222">;</span></span> <span class="line"></span> <span class="line"><span style="color:#BD2314">void</span><span style="color:#6200EE"> main</span><span style="color:#222222">() {</span></span> <span class="line"><span style="color:#6E6E70"> // Identify the root isolate to pass to the background isolate.</span></span> <span class="line"><span style="color:#0468D7"> RootIsolateToken</span><span style="color:#222222"> rootIsolateToken = </span><span style="color:#0468D7">RootIsolateToken</span><span style="color:#222222">.instance!;</span></span> <span class="line"><span style="color:#0468D7"> Isolate</span><span style="color:#222222">.</span><span style="color:#6200EE">spawn</span><span style="color:#222222">(_isolateMain, rootIsolateToken);</span></span> <span class="line"><span style="color:#222222">}</span></span> <span class="line"></span> <span class="line"><span style="color:#0468D7">Future</span><span style="color:#222222"><</span><span style="color:#BD2314">void</span><span style="color:#222222">> </span><span style="color:#6200EE">_isolateMain</span><span style="color:#222222">(</span><span style="color:#0468D7">RootIsolateToken</span><span style="color:#222222"> rootIsolateToken) </span><span style="color:#BD2314">async</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#6E6E70"> // Register the background isolate with the root isolate.</span></span> <span class="line"><span style="color:#0468D7"> BackgroundIsolateBinaryMessenger</span><span style="color:#222222">.</span><span style="color:#6200EE">ensureInitialized</span><span style="color:#222222">(rootIsolateToken);</span></span> <span class="line"></span> <span class="line"><span style="color:#6E6E70"> // You can now use the shared_preferences plugin.</span></span> <span class="line"><span style="color:#0468D7"> SharedPreferences</span><span style="color:#222222"> sharedPreferences = </span><span style="color:#BD2314">await</span><span style="color:#0468D7"> SharedPreferences</span><span style="color:#222222">.</span><span style="color:#6200EE">getInstance</span><span style="color:#222222">();</span></span> <span class="line"></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(sharedPreferences.</span><span style="color:#6200EE">getBool</span><span style="color:#222222">(</span><span style="color:#0C7064">'isDebug'</span><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="limitations-of-isolates">Limitations of Isolates</h2><a class="heading-link" href="#limitations-of-isolates" aria-label="Link to 'Limitations of Isolates' section">#</a></div><p>If you're coming to Dart from a language with multithreading, it's reasonable to expect isolates to behave like threads, but that isn't the case. Isolates have their own global fields, and can only communicate with message passing, ensuring that mutable objects in an isolate are only ever accessible in a single isolate. Therefore, isolates are limited by their access to their own memory. For example, if you have an application with a global mutable variable called <code>configuration</code>, it is copied as a new global field in a spawned isolate. If you mutate that variable in the spawned isolate, it remains untouched in the main isolate. This is true even if you pass the <code>configuration</code> object as a message to the new isolate. This is how isolates are meant to function, and it's important to keep in mind when you consider using isolates.</p><div class="header-wrapper"><h3 id="web-platforms-and-compute">Web platforms and compute</h3><a class="heading-link" href="#web-platforms-and-compute" aria-label="Link to 'Web platforms and compute' section">#</a></div><p>Dart web platforms, including Flutter web, don't support isolates. If you're targeting the web with your Flutter app, you can use the <code>compute</code> method to ensure your code compiles. The <a href="https://api.flutter.dev/flutter/foundation/compute.html"><code>compute()</code></a> method runs the computation on the main thread on the web, but spawns a new thread on mobile devices. On mobile and desktop platforms <code>await compute(fun, message)</code> is equivalent to <code>await Isolate.run(() => fun(message))</code>.</p><p>For more information on concurrency on the web, check out the <a href="https://dart.dev/language/concurrency">concurrency documentation</a> on dart.dev.</p><div class="header-wrapper"><h3 id="no-rootbundle-access-or-dart-ui-methods">No <code>rootBundle</code> access or <code>dart:ui</code> methods</h3><a class="heading-link" href="#no-rootbundle-access-or-dart-ui-methods" aria-label="Link to 'No rootBundle access or dart:ui methods' section">#</a></div><p>All UI tasks and Flutter itself are coupled to the main isolate. Therefore, you can't access assets using <code>rootBundle</code> in spawned isolates, nor can you perform any widget or UI work in spawned isolates.</p><div class="header-wrapper"><h3 id="limited-plugin-messages-from-host-platform-to-flutter">Limited plugin messages from host platform to Flutter</h3><a class="heading-link" href="#limited-plugin-messages-from-host-platform-to-flutter" aria-label="Link to 'Limited plugin messages from host platform to Flutter' section">#</a></div><p>With background isolate platform channels, you can use platform channels in isolates to send messages to the host platform (for example Android or iOS), and receive responses to those messages. However, you can't receive unsolicited messages from the host platform.</p><p>As an example, you can't set up a long-lived Firestore listener in a background isolate, because Firestore uses platform channels to push updates to Flutter, which are unsolicited. You can, however, query Firestore for a response in the background.</p><div class="header-wrapper"><h2 id="more-information">More information</h2><a class="heading-link" href="#more-information" aria-label="Link to 'More information' section">#</a></div><p>For more information on isolates, check out the following resources:</p><ul><li>If you're using many isolates, consider the <a href="https://api.flutter.dev/flutter/dart-ui/IsolateNameServer-class.html">IsolateNameServer</a> class in Flutter, or the pub package that clones the functionality for Dart applications not using Flutter.</li><li>Dart's Isolates are an implementation of the <a href="https://en.wikipedia.org/wiki/Actor_model">Actor model</a>.</li><li><a href="https://medium.com/@gaaclarke/isolate-agents-easy-isolates-for-flutter-6d75bf69a2e7">isolate_agents</a> is a package that abstracts Ports and make it easier to create long-lived isolates.</li><li>Read more about the <code>BackgroundIsolateBinaryMessenger</code> API <a href="https://medium.com/flutter/introducing-background-isolate-channels-7a299609cad8">announcement</a>.</li></ul><p id="page-github-links"><span>Unless stated otherwise, the documentation on this site reflects the latest stable version of Flutter. 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