[windows] wire the focus request and the focus events through the Windows platform #164296

mattkae · 2025-02-27T14:13:07Z

What's changed?

When a view is focused or unfocused, an event is now sent to the engine. This makes it so the proper view has focus when the corresponding window is focused. Thus, global shortcuts now work across views 🎉
Applications can request for a particular view to be focused, which causes the corresponding window to be focused
Wrote unit tests for all of this

How To Test

Merge windows/view_focus_event into canonical/foundation
Create a new app:

import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  final RegularWindowController controller1 = RegularWindowController(size: const Size(640, 480));
  final RegularWindowController controller2 = RegularWindowController(size: const Size(640, 480));
  runWidget(ViewCollection(
    views: [
      RegularWindow(controller: controller1, child: MyApp(otherController: controller2)),
      RegularWindow(controller: controller2, child: MyApp(otherController: controller1)),
    ]
  ));
}

class IncrementIntent extends Intent {
  const IncrementIntent();
}

class MyApp extends StatelessWidget {
  const MyApp({super.key, required this.otherController});

  final RegularWindowController otherController;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Shortcut Counter',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: CounterPage(otherController: otherController),
    );
  }
}

class CounterPage extends StatefulWidget {
  const CounterPage({super.key, required this.otherController});

  final RegularWindowController otherController;

  @override
  _CounterPageState createState() => _CounterPageState();
}

class _CounterPageState extends State<CounterPage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Shortcuts(
      shortcuts: {
        LogicalKeySet(LogicalKeyboardKey.space): const IncrementIntent(),
      },
      child: Actions(
        actions: {
          IncrementIntent: CallbackAction<IncrementIntent>(onInvoke: (intent) {
            _incrementCounter();
            return null;
          }),
        },
        child: Focus(
          autofocus: true,
          child: Scaffold(
            appBar: AppBar(title: const Text('Shortcut Counter')),
            body: Center(
              child: Column(children: [Text(
                'Counter: $_counter',
                style: const TextStyle(fontSize: 24),
              ),
              OutlinedButton(onPressed: () {
                WidgetsBinding.instance.platformDispatcher.requestViewFocusChange(
                  direction: ViewFocusDirection.forward,
                  state: ViewFocusState.focused,
                  viewId: widget.otherController.rootView.viewId,
                );
              }, child: const Text('Focus other window'))]),
            ),
          ),
        ),
      ),
    );
  }
}

Run with:

flutter run --debug --local-engine-src-path C:/dev/flutter/engine/src/ --local-engine host_debug_unopt --local-engine-host host_debug_unopt lib/main.dart  --enable-multi-window

Pressing spacebar while either window is focused should make the corresponding counter go up
Clicking the button on either window should make the other window become focused

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, or this PR is test-exempt.
I followed the breaking change policy and added Data Driven Fixes where supported.
All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

hbatagelo

I've noticed that FlutterHostWindow in canonical:foundation needs some updates to use this new API instead of directly calling the native SetFocus; otherwise, the reference app gets stuck in a loop, switching focus between the main window and the secondary regular windows. I can take care of that as soon as this lands.

engine/src/flutter/shell/platform/windows/flutter_window_unittests.cc

engine/src/flutter/shell/platform/windows/flutter_window.cc

loic-sharma · 2025-03-05T00:29:56Z

engine/src/flutter/shell/platform/windows/flutter_window.cc

+      if (binding_handler_delegate_) {
+        binding_handler_delegate_->OnFocus(
+            FlutterViewFocusState::kFocused,
+            FlutterViewFocusDirection::kUndefined);


Should there be a focus direction if a window has two views, and using the tab key I move the focus forward from view 1 to view 2? If yes, could we add a TODO comment here with an issue to track this work?

@knopp Do you have any insight here?

Is that a use case we want to support? On macOS for example the event will be wired to top level window, mostly because it's not always FlutterView that actually has the focus (i.e. during IME and Voiceover).

I think if we want to support multiple flutter views in the same window that's going to require a design doc at very least.

Understood. We want to support multiple views in the same window, but at the moment there is no way to focus those sub-views since they are not tied to anything and therefore won't actually cause a "Focus" event

engine/src/flutter/shell/platform/windows/flutter_windows_view.cc

loic-sharma

Looks great, nice work!

… the Windows platform (flutter/flutter#164296)

flutter/flutter@2578d97...321fbc0 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from fefecd49e03a to ccd8cc23aa94 (1 revision) (flutter/flutter#164712) 2025-03-06 mdebbar@google.com [web] Detect scrollable semantics nodes more reliably (flutter/flutter#164491) 2025-03-06 matt.kosarek@canonical.com [windows] wire the focus request and the focus events through the Windows platform (flutter/flutter#164296) 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from 02897747c7d5 to fefecd49e03a (1 revision) (flutter/flutter#164701) 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from e315b0ab7c84 to 02897747c7d5 (1 revision) (flutter/flutter#164677) 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from 0c3880f94970 to e315b0ab7c84 (1 revision) (flutter/flutter#164669) 2025-03-06 jonahwilliams@google.com [Impeller] use device private on non-iOS devices. (flutter/flutter#164601) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 43294a662fd0 to 0c3880f94970 (1 revision) (flutter/flutter#164661) 2025-03-05 codefu@google.com Add a workflow (only triggered from rest events) for hasing experiment (flutter/flutter#164657) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 4cf9f0b77d41 to 43294a662fd0 (4 revisions) (flutter/flutter#164649) 2025-03-05 50643541+Mairramer@users.noreply.github.com Adds animateToItem to the CarouselController (flutter/flutter#162694) 2025-03-05 30870216+gaaclarke@users.noreply.github.com Cleanup content context (flutter/flutter#164229) 2025-03-05 34465683+rkishan516@users.noreply.github.com Fix: Update CupertinoSheetRoute transition rounded corner (flutter/flutter#163700) 2025-03-05 jonahwilliams@google.com [Impeller] fix macOS managed memory. (flutter/flutter#164635) 2025-03-05 jacksongardner@google.com [skwasm] Clear font collection cache when font is loaded manually. (flutter/flutter#164588) 2025-03-05 victorsanniay@gmail.com Fix race condition causing crash when interacting with an animating scrollable (flutter/flutter#164392) 2025-03-05 58529443+srujzs@users.noreply.github.com Use dwds 24.3.6 and pass uri for the reload scripts path to FrontendServerDdcLibraryBundleProvider (flutter/flutter#164582) 2025-03-05 engine-flutter-autoroll@skia.org Roll Packages from 9e4684e to abba683 (8 revisions) (flutter/flutter#164630) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 7e4323f72c9d to 4cf9f0b77d41 (1 revision) (flutter/flutter#164622) 2025-03-05 harri.kirik@lab.mobi Fix to Linux_pixel_7pro integration_ui_keyboard_resize test flakiness (flutter/flutter#162308) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 03a3f653d64e to 7e4323f72c9d (1 revision) (flutter/flutter#164599) 2025-03-05 34871572+gmackall@users.noreply.github.com Implement `clipPath` Mutator for hcpp (flutter/flutter#164525) 2025-03-05 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[Impeller] use DeviceLocal textures for gifs on non-iOS devices. (#164573)" (flutter/flutter#164600) 2025-03-05 jonahwilliams@google.com [macos] prefer integrated GPU. (flutter/flutter#164569) 2025-03-05 muhatashim@google.com Enforce minSdk constraint for Android Flutter (flutter/flutter#164251) 2025-03-05 dkwingsmt@users.noreply.github.com Add `clipRSuperellipse`, and use them for dialogs (flutter/flutter#161111) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 46705a22edc3 to 03a3f653d64e (1 revision) (flutter/flutter#164590) 2025-03-05 psturm@esri.com when resetting FlutterPlatformViewsController, clear out some additional internal state to prevent it from carrying over across a Hot Restart (flutter/flutter#164456) 2025-03-05 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from Rt6pxGFLVAJHduM0V... to fhm5z889sA5T1AQao... (flutter/flutter#164583) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC stuartmorgan@google.com,tarrinneal@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

… the Windows platform (flutter/flutter#164296)

flutter/flutter@2578d97...321fbc0 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from fefecd49e03a to ccd8cc23aa94 (1 revision) (flutter/flutter#164712) 2025-03-06 mdebbar@google.com [web] Detect scrollable semantics nodes more reliably (flutter/flutter#164491) 2025-03-06 matt.kosarek@canonical.com [windows] wire the focus request and the focus events through the Windows platform (flutter/flutter#164296) 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from 02897747c7d5 to fefecd49e03a (1 revision) (flutter/flutter#164701) 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from e315b0ab7c84 to 02897747c7d5 (1 revision) (flutter/flutter#164677) 2025-03-06 engine-flutter-autoroll@skia.org Roll Skia from 0c3880f94970 to e315b0ab7c84 (1 revision) (flutter/flutter#164669) 2025-03-06 jonahwilliams@google.com [Impeller] use device private on non-iOS devices. (flutter/flutter#164601) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 43294a662fd0 to 0c3880f94970 (1 revision) (flutter/flutter#164661) 2025-03-05 codefu@google.com Add a workflow (only triggered from rest events) for hasing experiment (flutter/flutter#164657) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 4cf9f0b77d41 to 43294a662fd0 (4 revisions) (flutter/flutter#164649) 2025-03-05 50643541+Mairramer@users.noreply.github.com Adds animateToItem to the CarouselController (flutter/flutter#162694) 2025-03-05 30870216+gaaclarke@users.noreply.github.com Cleanup content context (flutter/flutter#164229) 2025-03-05 34465683+rkishan516@users.noreply.github.com Fix: Update CupertinoSheetRoute transition rounded corner (flutter/flutter#163700) 2025-03-05 jonahwilliams@google.com [Impeller] fix macOS managed memory. (flutter/flutter#164635) 2025-03-05 jacksongardner@google.com [skwasm] Clear font collection cache when font is loaded manually. (flutter/flutter#164588) 2025-03-05 victorsanniay@gmail.com Fix race condition causing crash when interacting with an animating scrollable (flutter/flutter#164392) 2025-03-05 58529443+srujzs@users.noreply.github.com Use dwds 24.3.6 and pass uri for the reload scripts path to FrontendServerDdcLibraryBundleProvider (flutter/flutter#164582) 2025-03-05 engine-flutter-autoroll@skia.org Roll Packages from 9e4684e to abba683 (8 revisions) (flutter/flutter#164630) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 7e4323f72c9d to 4cf9f0b77d41 (1 revision) (flutter/flutter#164622) 2025-03-05 harri.kirik@lab.mobi Fix to Linux_pixel_7pro integration_ui_keyboard_resize test flakiness (flutter/flutter#162308) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 03a3f653d64e to 7e4323f72c9d (1 revision) (flutter/flutter#164599) 2025-03-05 34871572+gmackall@users.noreply.github.com Implement `clipPath` Mutator for hcpp (flutter/flutter#164525) 2025-03-05 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[Impeller] use DeviceLocal textures for gifs on non-iOS devices. (#164573)" (flutter/flutter#164600) 2025-03-05 jonahwilliams@google.com [macos] prefer integrated GPU. (flutter/flutter#164569) 2025-03-05 muhatashim@google.com Enforce minSdk constraint for Android Flutter (flutter/flutter#164251) 2025-03-05 dkwingsmt@users.noreply.github.com Add `clipRSuperellipse`, and use them for dialogs (flutter/flutter#161111) 2025-03-05 engine-flutter-autoroll@skia.org Roll Skia from 46705a22edc3 to 03a3f653d64e (1 revision) (flutter/flutter#164590) 2025-03-05 psturm@esri.com when resetting FlutterPlatformViewsController, clear out some additional internal state to prevent it from carrying over across a Hot Restart (flutter/flutter#164456) 2025-03-05 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from Rt6pxGFLVAJHduM0V... to fhm5z889sA5T1AQao... (flutter/flutter#164583) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC stuartmorgan@google.com,tarrinneal@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

mattkae added 8 commits February 25, 2025 14:11

(wip) initial send focus, not sure if it works

b381920

Sending the focus event

6eb8309

Fixing remaining problems

70cd122

Formatting

b0ae943

Updating tests per expected behavior

24b28df

wip

b422b48

That might build

4ab767d

Fixes for building on Windows

066489b

github-actions bot added engine flutter/engine repository. See also e: labels. platform-windows Building on or for Windows specifically a: desktop Running on desktop labels Feb 27, 2025

mattkae changed the title ~~Windows/view focus event~~ [windows] wire the focus request and the focus events through the windows platform Feb 27, 2025

mattkae changed the title ~~[windows] wire the focus request and the focus events through the windows platform~~ [windows] wire the focus request and the focus events through the Windows platform Feb 27, 2025

mattkae requested review from knopp, loic-sharma, robert-ancell and hbatagelo February 27, 2025 15:53

mattkae marked this pull request as ready for review February 27, 2025 15:54

mattkae added 2 commits February 27, 2025 15:05

Tests minus the Flutter Windows Engine

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FlutterWindowsEngine unit tests

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hbatagelo requested changes Feb 28, 2025

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mattkae requested a review from hbatagelo March 3, 2025 13:39

mattkae added 2 commits March 3, 2025 13:38

Pull request feedback

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Merge branch 'master' into windows/view_focus_event

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loic-sharma reviewed Mar 5, 2025

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loic-sharma approved these changes Mar 5, 2025

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Remove accidental comment change

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mattkae enabled auto-merge March 6, 2025 13:38

hbatagelo approved these changes Mar 6, 2025

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mattkae added this pull request to the merge queue Mar 6, 2025

Merged via the queue into flutter:master with commit 099e6d3 Mar 6, 2025
174 of 176 checks passed

mattkae deleted the windows/view_focus_event branch March 6, 2025 14:12

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Roll Flutter from 2578d97f32c8 to 099e6d39fe38 (27 revisions) flutter/packages#8806

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099e6d3 [windows] wire the focus request and the focus events through…

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… the Windows platform (flutter/flutter#164296)

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Roll Flutter from 2578d97f32c8 to d778ed25a485 (28 revisions) flutter/packages#8807

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099e6d3 [windows] wire the focus request and the focus events through…

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… the Windows platform (flutter/flutter#164296)

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Roll Flutter from 2578d97f32c8 to 321fbc0e7e81 (29 revisions) flutter/packages#8808

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099e6d3 [windows] wire the focus request and the focus events through…

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… the Windows platform (flutter/flutter#164296)

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099e6d3 [windows] wire the focus request and the focus events through…

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… the Windows platform (flutter/flutter#164296)

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099e6d3 [windows] wire the focus request and the focus events through…

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How To Test

Pre-launch Checklist

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