Add WidgetStatesController support to ExpansionTile by iamvikashtiwari · Pull Request #181238 · flutter/flutter

iamvikashtiwari · 2026-01-21T08:51:31Z

This PR adds support for providing a WidgetStatesController to ExpansionTile
and forwards it to the backing ListTile. This allows callers to observe and
control hovered, pressed, and focused states of the tile header.

The change includes updated documentation with a snippet example and adds
test coverage for both provided and null statesController cases.

Fixes #180161

Pre-launch Checklist

I read the Contributor Guide and followed the process outlined there for submitting PRs.
I read the Tree Hygiene wiki page, which explains my responsibilities.
I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
I signed the CLA.
I listed at least one issue that this PR fixes in the description above.
I updated/added relevant documentation (doc comments with ///).
I added new tests to check the change I am making.
I followed the breaking change policy and added Data Driven Fixes where supported.
All existing and new tests are passing.

gemini-code-assist

Code Review

This pull request adds WidgetStatesController support to ExpansionTile, which is a valuable enhancement for observing and controlling its interactive states. The implementation is straightforward and includes appropriate tests. My main feedback is on the example code provided in the documentation, which should be updated to correctly manage the lifecycle of the WidgetStatesController to prevent memory leaks and follow best practices.

gemini-code-assist · 2026-01-21T08:53:33Z

+  /// class ExpansionTileStatesExample extends StatelessWidget {
+  ///   ExpansionTileStatesExample({super.key});
+  ///
+  ///   final WidgetStatesController controller = WidgetStatesController();
+  ///
+  ///   @override
+  ///   Widget build(BuildContext context) {
+  ///     controller.addListener(() {
+  ///       if (controller.value.contains(WidgetState.hovered)) {
+  ///         debugPrint('Tile is hovered');
+  ///       }
+  ///     });
+  ///
+  ///     return MaterialApp(
+  ///       home: Scaffold(
+  ///         body: ExpansionTile(
+  ///           title: const Text('Settings'),
+  ///           statesController: controller,
+  ///         ),
+  ///       ),
+  ///     );
+  ///   }
+  /// }


The example ExpansionTileStatesExample should be a StatefulWidget to properly manage the lifecycle of the WidgetStatesController. WidgetStatesController is a ChangeNotifier and needs to be disposed to avoid memory leaks. Currently, it's created in a StatelessWidget, which doesn't have a dispose method.

Additionally, adding a listener inside the build method can lead to adding the same listener multiple times, as build can be called repeatedly. The listener should be added in initState.

/// class ExpansionTileStatesExample extends StatefulWidget { /// const ExpansionTileStatesExample({super.key}); /// /// @override /// State<ExpansionTileStatesExample> createState() => _ExpansionTileStatesExampleState(); /// } /// /// class _ExpansionTileStatesExampleState extends State<ExpansionTileStatesExample> { /// late final WidgetStatesController _controller; /// /// @override /// void initState() { /// super.initState(); /// _controller = WidgetStatesController(); /// _controller.addListener(() { /// if (_controller.value.contains(WidgetState.hovered)) { /// debugPrint('Tile is hovered'); /// } /// }); /// } /// /// @override /// void dispose() { /// _controller.dispose(); /// super.dispose(); /// } /// /// @override /// Widget build(BuildContext context) { /// return MaterialApp( /// home: Scaffold( /// body: ExpansionTile( /// title: const Text('Settings'), /// statesController: _controller, /// ), /// ), /// ); /// } /// }

@iamvikashtiwari This looks like a real problem that should be addressed

Oh I missed this. For code snippet, maybe we should make it shorter? I didn't see a whole class example in code snippet previously. Maybe check the other use cases as examples.

It looks like other WidgetStatesController fields don't provide a code example. However, it seems useful to have at least one example of this pattern.

I'd consider:

Move this code example to be a full sample: examples/api/lib/widgets/widget_state/widget_states_controller.0.dart

Add unit tests for this sample

Add this code example to WidgetStatesController's docs directly using a {@tool dartpad} (instead of a {@tool snippet}).

Gentle ping just in case this comment is missed:)!

QuncCccccc

We might need to fix the failed tests and also the comments from the closed PR:) Thanks!

QuncCccccc · 2026-01-21T17:33:07Z

    );
  });
+
+  testWidgets('ExpansionTile forwards statesController to ListTile', (tester) async {


Run dart format packages/flutter/test/material/expansion_tile_test.dart to fix linux analyzer.

Thanks for pointing this out!

I’ve fixed the formatting issue in
packages/flutter/test/material/expansion_tile_test.dart
by running dart format and pushed the update.

QuncCccccc · 2026-01-28T02:39:08Z

  });
+
+  testWidgets('ExpansionTile forwards statesController to ListTile', (tester) async {
+    final controller = WidgetStatesController();


We need to dispose controller when we finish testing. Adding addTearDown(controller.dispose); after this line should fix the failed "Windows framework_tests_libraries_leak_tracking" test.

Thanks for the suggestion!

Added addTearDown(controller.dispose); to properly dispose the
WidgetStatesController in the test. This should resolve the
Windows leak tracking failure.

QuncCccccc · 2026-01-30T20:44:35Z

+    expect(listTile.statesController, controller);
+  });
+
+  testWidgets('ExpansionTile forwards statesController to ListTile', (tester) async {


We have 2 identical "ExpansionTile forwards statesController to ListTile" tests now. I think originally this is "ExpansionTile forwards null statesController to ListTile".

QuncCccccc · 2026-01-30T20:46:28Z

  });
+
+  testWidgets('ExpansionTile forwards statesController to ListTile', (tester) async {
+    final controller = WidgetStatesController();


Suggested change

final controller = WidgetStatesController();

final controller = WidgetStatesController();

addTearDown(controller.dispose);

loic-sharma · 2026-02-02T19:36:04Z

  // the default value to true.
  final bool internalAddSemanticForOnTap;

+  /// {@tool snippet}


We should add a summary sentence so that IDEs like VS Code show useful code completion information if you type myExpansionTile.statesController. Consider something like:

Suggested change

/// {@tool snippet}

/// The controller that notifies when the widget's [WidgetState]s change.

///

/// {@tool snippet}

QuncCccccc · 2026-02-09T19:32:45Z

Gentle ping for this comment here. If you think this is too much, I'm okay with removing the code snippet completely as well since I think this example looks simple.

iamvikashtiwari · 2026-02-14T16:29:05Z

Thanks! Since the usage is straightforward, I’ve removed the snippet to keep the documentation concise.

QuncCccccc

LGTM. Thanks!

justinmc

LGTM 👍 . Always good to have more WidgetStatesController support.

iamvikashtiwari · 2026-02-19T05:02:47Z

Thanks everyone for the reviews and guidance!

auto-submit · 2026-02-20T21:10:39Z

autosubmit label was removed for flutter/flutter/181238, because The base commit of the PR is older than 7 days and can not be merged. Please merge the latest changes from the main into this branch and resubmit the PR.

…r/flutter#181238)

This PR adds support for providing a `WidgetStatesController` to `ExpansionTile` and forwards it to the backing `ListTile`. This allows callers to observe and control hovered, pressed, and focused states of the tile header. The change includes updated documentation with a snippet example and adds test coverage for both provided and null `statesController` cases. Fixes flutter#180161 ## Pre-launch Checklist - [x] I read the Contributor Guide and followed the process outlined there for submitting PRs. - [x] I read the Tree Hygiene wiki page, which explains my responsibilities. - [x] I read and followed the Flutter Style Guide, including Features we expect every widget to implement. - [x] I signed the CLA. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making. - [ ] I followed the breaking change policy and added Data Driven Fixes where supported. - [ ] All existing and new tests are passing.

…r/flutter#181238)

This PR adds support for providing a `WidgetStatesController` to `ExpansionTile` and forwards it to the backing `ListTile`. This allows callers to observe and control hovered, pressed, and focused states of the tile header. The change includes updated documentation with a snippet example and adds test coverage for both provided and null `statesController` cases. Fixes flutter#180161 ## Pre-launch Checklist - [x] I read the Contributor Guide and followed the process outlined there for submitting PRs. - [x] I read the Tree Hygiene wiki page, which explains my responsibilities. - [x] I read and followed the Flutter Style Guide, including Features we expect every widget to implement. - [x] I signed the CLA. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making. - [ ] I followed the breaking change policy and added Data Driven Fixes where supported. - [ ] All existing and new tests are passing.

github-actions Bot added framework flutter/packages/flutter repository. See also f: labels. f: material design flutter/packages/flutter/material repository. labels Jan 21, 2026

gemini-code-assist Bot reviewed Jan 21, 2026

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iamvikashtiwari mentioned this pull request Jan 21, 2026

Add WidgetStatesController support to ExpansionTile #180955

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QuncCccccc reviewed Jan 21, 2026

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QuncCccccc reviewed Jan 28, 2026

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This was referenced Jan 28, 2026

Add statesController to ExpansionTile #181610

Closed

ExpansionTile should accept a WidgetStatesController for its backing ListTile #180161

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QuncCccccc reviewed Jan 30, 2026

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loic-sharma reviewed Feb 2, 2026

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Comment thread packages/flutter/test/material/expansion_tile_test.dart

dkwingsmt requested a review from QuncCccccc February 18, 2026 19:15

QuncCccccc approved these changes Feb 18, 2026

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justinmc approved these changes Feb 18, 2026

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QuncCccccc added the autosubmit Merge PR when tree becomes green via auto submit App label Feb 20, 2026

auto-submit Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Feb 20, 2026

iamvikashtiwari added 9 commits February 25, 2026 16:06

Add WidgetStatesController support to ExpansionTile

30b7872

Fix formatting in ExpansionTile statesController tests

cd669b4

Dispose WidgetStatesController in ExpansionTile tests

0d4f1dd

Dispose WidgetStatesController in ExpansionTile tests

f0e7d1e

Dispose WidgetStatesController and fix ExpansionTile tests

23e1dd7

Fix Linux analyzer by simplifying test teardown

ae5304b

Fix ExpansionTile test analyzer lint

dbbb242

Format ExpansionTile tests to satisfy analyzer

3345f28

Simplify ExpansionTile statesController documentation

0824901

iamvikashtiwari force-pushed the improve-app-flavor-clean branch from bbffc1f to 0824901 Compare February 25, 2026 10:37

dkwingsmt added the autosubmit Merge PR when tree becomes green via auto submit App label Feb 25, 2026

auto-submit Bot added this pull request to the merge queue Feb 25, 2026

Merged via the queue into flutter:master with commit 8af3c74 Feb 25, 2026
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flutter-dashboard Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Feb 25, 2026

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Roll Flutter from dad6f9d4107a to b7ac273fa060 (69 revisions) flutter/packages#11126

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Roll Flutter from dad6f9d4107a to b7ac273fa060 (69 revisions) flutter/packages#11132

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8af3c74ec Add WidgetStatesController support to ExpansionTile (flutte…

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8af3c74ec Add WidgetStatesController support to ExpansionTile (flutte…

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Roll Flutter from b31548feb941 to eb69f4847e44 (54 revisions) flutter/packages#11135

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Flutter Notable Commits - 2026 #181433

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	final controller = WidgetStatesController();
	final controller = WidgetStatesController();
	addTearDown(controller.dispose);

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iamvikashtiwari commented Jan 21, 2026

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QuncCccccc Jan 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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