Deprecated the window singleton

What changed?

In preparation for supporting multiple views and multiple windows, the `window` singleton has been deprecated. Code previously relying on the `window` singleton needs to look up the specific view it wants to operate on via the `View.of` API or interact with the `PlatformDispatcher` directly.

Original behavior

Originally, Flutter assumed that an application would only consist of a single view (the `window`) into which content can be drawn. In a multi-view world, this assumption no longer makes sense and the APIs encoding this assumption have been deprecated. Instead, applications and libraries that relied on these APIs must choose a specific view they want to operate on and migrate to new multi-view compatible APIs as outlined in this migration guide.

New behavior

The APIs that have been deprecated as part of this change are:

Will this affect my application?

Who is affected: Code that still calls the deprecated API; it keeps working until removal but produces analyzer warnings. Code that uses View.of, PlatformDispatcher, BaseBinding and related APIs.
Practical impact: Warnings now; removal in a future release. Plan the migration but no immediate break.
What action should I take?: Follow the official migration guide below, update affected call sites, run `dart fix --apply` where a fix is available, then run your tests.

APIs mentioned:View.of PlatformDispatcher BaseBinding GestureBinding.instance.window SchedulerBinding.instance.window ServicesBinding.instance.window PaintingBinding.instance.window SemanticsBinding.instance.window RendererBinding.instance.window WidgetsBinding.instance.window WidgetTester.binding.window SingletonFlutterView

How do I migrate safely?

Before and after (from the official guide)

dart+2−2

Before

1		Widget build(BuildContext context) {
2	−	final double dpr = WidgetsBinding.instance.window.devicePixelRatio;
3	−	final Locale locale = WidgetsBinding.instance.window.locale;
4		return Text('The device pixel ratio is $dpr and the locale is $locale.');
5		}

After

1		Widget build(BuildContext context) {
2	+	final double dpr = View.of(context).devicePixelRatio;
3	+	final Locale locale = View.of(context).platformDispatcher.locale;
4		return Text('The device pixel ratio is $dpr and the locale is $locale.');
5		}

Raw before / after

Widget build(BuildContext context) {
  final double dpr = WidgetsBinding.instance.window.devicePixelRatio;
  final Locale locale = WidgetsBinding.instance.window.locale;
  return Text('The device pixel ratio is $dpr and the locale is $locale.');
}

Widget build(BuildContext context) {
  final double dpr = View.of(context).devicePixelRatio;
  final Locale locale = View.of(context).platformDispatcher.locale;
  return Text('The device pixel ratio is $dpr and the locale is $locale.');
}

Official migration guide (excerpt, © The Flutter Authors, CC BY 3.0)

Instead of accessing the static window property, application and library code that has access to a BuildContext should use View.of to look up the FlutterView the context is associated with. Some properties have moved to the PlatformDispatcher accessible from the view via the platformDispatcher getter.

Code before migration:

Widget build(BuildContext context) {
  final double dpr = WidgetsBinding.instance.window.devicePixelRatio;
  final Locale locale = WidgetsBinding.instance.window.locale;
  return Text('The device pixel ratio is $dpr and the locale is $locale.');
}

Code after migration:

Widget build(BuildContext context) {
  final double dpr = View.of(context).devicePixelRatio;
  final Locale locale = View.of(context).platformDispatcher.locale;
  return Text('The device pixel ratio is $dpr and the locale is $locale.');
}

If no BuildContext is available, the PlatformDispatcher exposed by the bindings can be consulted directly.

Code before migration:

double getTextScaleFactor() {
  return WidgetsBinding.instance.window.textScaleFactor;
}

Code after migration:

double getTextScaleFactor() {
  // View.of(context).platformDispatcher.textScaleFactor if a BuildContext is available, otherwise:
  return WidgetsBinding.instance.platformDispatcher.textScaleFactor;
}

Testing

In tests written with testWidget, the new view and platformDispatcher accessors should be used instead.

Setting view-specific properties

TestFlutterView has also made an effort to make the test API clearer and more concise by using setters with the same name as their related getter instead of setters with the TestValue suffix.

Code before migration:

testWidget('test name', (WidgetTester tester) async {
  tester.binding.window.devicePixelRatioTestValue = 2.0;
  tester.binding.window.displayFeaturesTestValue = &#x3C;DisplayFeatures>[];
  tester.binding.window.gestureSettingsTestValue = const GestureSettings(physicalTouchSlop: 100);
  tester.binding.window.paddingTestValue = FakeViewPadding.zero;
  tester.binding.window.physicalGeometryTestValue = const Rect.fromLTRB(0,0, 500, 800);
  tester.binding.window.physicalSizeTestValue = const Size(300, 400);
  tester.binding.window.systemGestureInsetsTestValue = FakeViewPadding.zero;
  tester.binding.window.viewInsetsTestValue = FakeViewPadding.zero;
  tester.binding.window.viewPaddingTestValue = FakeViewPadding.zero;
});

Code after migration

testWidget('test name', (WidgetTester tester) async {
  tester.view.devicePixelRatio = 2.0;
  tester.view.displayFeatures = &#x3C;DisplayFeatures>[];
  tester.view.gestureSettings = const GestureSettings(physicalTouchSlop: 100);
  tester.view.padding = FakeViewPadding.zero;
  tester.view.physicalGeometry = const Rect.fromLTRB(0,0, 500, 800);
  tester.view.physicalSize = const Size(300, 400);
  tester.view.systemGestureInsets = FakeViewPadding.zero;
  tester.view.viewInsets = FakeViewPadding.zero;
  tester.view.viewPadding = FakeViewPadding.zero;
});

Resetting view-specific properties

TestFlutterView retains the capability to reset individual properties or the entire view but, in order to be more clear and consist, the naming of these methods has changed from clear<property>TestValue and clearAllTestValues to reset<property> and reset respectively.

Resetting individual properties

Code before migration:

testWidget('test name', (WidgetTester tester) async {
  addTearDown(tester.binding.window.clearDevicePixelRatioTestValue);
  addTearDown(tester.binding.window.clearDisplayFeaturesTestValue);
  addTearDown(tester.binding.window.clearGestureSettingsTestValue);
  addTearDown(tester.binding.window.clearPaddingTestValue);
  addTearDown(tester.binding.window.clearPhysicalGeometryTestValue);
  addTearDown(tester.binding.window.clearPhysicalSizeTestValue);
  addTearDown(tester.binding.window.clearSystemGestureInsetsTestValue);
  addTearDown(tester.binding.window.clearViewInsetsTestValue);
  addTearDown(tester.binding.window.clearViewPaddingTestValue);
});

Code after migration

testWidget('test name', (WidgetTester tester) async {
  addTearDown(tester.view.resetDevicePixelRatio);
  addTearDown(tester.view.resetDisplayFeatures);
  addTearDown(tester.view.resetGestureSettings);
  addTearDown(tester.view.resetPadding);
  addTearDown(tester.view.resetPhysicalGeometry);
  addTearDown(tester.view.resetPhysicalSize);
  addTearDown(tester.view.resetSystemGestureInsets);
  addTearDown(tester.view.resetViewInsets);
  addTearDown(tester.view.resetViewPadding);
});

Resetting all properties at once

Code before migration:

testWidget('test name', (WidgetTester tester) async {
  addTearDown(tester.binding.window.clearAllTestValues);
});

Code after migration

testWidget('test name', (WidgetTester tester) async {
  addTearDown(tester.view.reset);
});

Setting platform-specific properties

TestPlatformDispatcher retains the same functionality and naming scheme for test setters as did TestWindow, so migration of platform-specific properties mainly consists of calling the same setters on the new WidgetTester.platformDispatcher accessor.

Code before migration:

testWidgets('test name', (WidgetTester tester) async {
  tester.binding.window.accessibilityFeaturesTestValue = FakeAccessibilityFeatures.allOn;
  tester.binding.window.alwaysUse24HourFormatTestValue = false;
  tester.binding.window.brieflyShowPasswordTestValue = true;
  tester.binding.window.defaultRouteNameTestValue = '/test';
  tester.binding.window.initialLifecycleStateTestValue = 'painting';
  tester.binding.window.localesTestValue = &#x3C;Locale>[const Locale('en-us'), const Locale('ar-jo')];
  tester.binding.window.localeTestValue = const Locale('ar-jo');
  tester.binding.window.nativeSpellCheckServiceDefinedTestValue = false;
  tester.binding.window.platformBrightnessTestValue = Brightness.dark;
  tester.binding.window.semanticsEnabledTestValue = true;
  tester.binding.window.textScaleFactorTestValue = 2.0;
});

Code after migration:

testWidgets('test name', (WidgetTester tester) async {
  tester.platformDispatcher.accessibilityFeaturesTestValue = FakeAccessibilityFeatures.allOn;
  tester.platformDispatcher.alwaysUse24HourFormatTestValue = false;
  tester.platformDispatcher.brieflyShowPasswordTestValue = true;
  tester.platformDispatcher.defaultRouteNameTestValue = '/test';
  tester.platformDispatcher.initialLifecycleStateTestValue = 'painting';
  tester.platformDispatcher.localesTestValue = &#x3C;Locale>[const Locale('en-us'), const Locale('ar-jo')];
  tester.platformDispatcher.localeTestValue = const Locale('ar-jo');
  tester.platformDispatcher.nativeSpellCheckServiceDefinedTestValue = false;
  tester.platformDispatcher.platformBrightnessTestValue = Brightness.dark;
  tester.platformDispatcher.semanticsEnabledTestValue = true;
  tester.platformDispatcher.textScaleFactorTestValue = 2.0;
});

Resetting platform-specific properties

Similarly to setting properties, resetting platform-specific properties consists mainly of changing from the binding.window accessor to the platformDispatcher accessor.

Resetting individual properties

Code before migration:

testWidgets('test name', (WidgetTester tester) async {
  addTeardown(tester.binding.window.clearAccessibilityFeaturesTestValue);
  addTeardown(tester.binding.window.clearAlwaysUse24HourFormatTestValue);
  addTeardown(tester.binding.window.clearBrieflyShowPasswordTestValue);
  addTeardown(tester.binding.window.clearDefaultRouteNameTestValue);
  addTeardown(tester.binding.window.clearInitialLifecycleStateTestValue);
  addTeardown(tester.binding.window.clearLocalesTestValue);
  addTeardown(tester.binding.window.clearLocaleTestValue);
  addTeardown(tester.binding.window.clearNativeSpellCheckServiceDefinedTestValue);
  addTeardown(tester.binding.window.clearPlatformBrightnessTestValue);
  addTeardown(tester.binding.window.clearSemanticsEnabledTestValue);
  addTeardown(tester.binding.window.clearTextScaleFactorTestValue);
});

Code after migration:

testWidgets('test name', (WidgetTester tester) async {
  addTeardown(tester.platformDispatcher.clearAccessibilityFeaturesTestValue);
  addTeardown(tester.platformDispatcher.clearAlwaysUse24HourFormatTestValue);
  addTeardown(tester.platformDispatcher.clearBrieflyShowPasswordTestValue);
  addTeardown(tester.platformDispatcher.clearDefaultRouteNameTestValue);
  addTeardown(tester.platformDispatcher.clearInitialLifecycleStateTestValue);
  addTeardown(tester.platformDispatcher.clearLocalesTestValue);
  addTeardown(tester.platformDispatcher.clearLocaleTestValue);
  addTeardown(tester.platformDispatcher.clearNativeSpellCheckServiceDefinedTestValue);
  addTeardown(tester.platformDispatcher.clearPlatformBrightnessTestValue);
  addTeardown(tester.platformDispatcher.clearSemanticsEnabledTestValue);
  addTeardown(tester.platformDispatcher.clearTextScaleFactorTestValue);
});

Resetting all properties at once

Code before migration:

testWidgets('test name', (WidgetTester tester) async {
  addTeardown(tester.binding.window.clearAllTestValues);
});

Code after migration:

testWidgets('test name', (WidgetTester tester) async {
  addTeardown(tester.platformDispatcher.clearAllTestValues);
});

Migration assistantAI-generated · grounded in cited sources

AI explanations are not configured

Set AI_PROVIDER (for example to openai-compatible with a local Ollama or LM Studio endpoint) to enable grounded explanations. Everything else on this page works without an AI provider.

Evidence & verification

Official migration guide·Verified classification (90%)

Listed in the official breaking-changes index; title states deprecation.

An official announcement or migration guide documents an intended behaviour or API change. A verified source change (git diff) shows code changed but does not by itself prove a public API is breaking. AI interpretations are labelled and never used to classify a change.

Validation warnings

api-symbols: {"reason":"no referenced symbol found in the current API index","unresolved":["View.of","PlatformDispatcher","BaseBinding","GestureBinding.instance.window","SchedulerBinding.instance.window","ServicesBinding.instance.window","PaintingBinding.instance.window","SemanticsBinding.instance.window","RendererBinding.instance.window","WidgetsBinding.instance.window","WidgetTester.binding.window","SingletonFlutterView","TestWindow","BuildContext","FlutterView","FlutterView.platformDispatcher","PlatformDispatcher.views","WidgetsBinding.instance.platformDispatcher","PlatformDispatcher.instance","WidgetTester.view","TestFlutterView","WidgetTester.viewOf","WidgetTester.platformDispatcher","TestPlatformDispatcher","TestValue","TestWidgetsFlutterBinding.window"]}

Source commit: b3045439b7c0
Source last updated: Oct 21, 2026
Last synchronized: Oct 21, 2026
Publication status: published

Publication history

Oct 21, 2026, 8:31 PM: new → published (ingestion) — Backed by an official breaking-change/migration guide.

AI explanationAI-generated · grounded in cited sources

AI explanations are not configured

Set AI_PROVIDER (for example to openai-compatible with a local Ollama or LM Studio endpoint) to enable grounded explanations. Everything else on this page works without an AI provider.

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