[iOS] Hide keyboard on hot restart #167013

loic-sharma · 2025-04-11T22:20:58Z

This hides the keyboard and text input context menu if you hot restart your iOS app.

Before	After
Before.MP4	After.MP4

Part of #10713

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.

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterTextInputPlugin.mm

engine/src/flutter/shell/platform/darwin/ios/platform_view_ios.mm

dev/devicelab/lib/tasks/keyboard_hot_restart_test.dart

hellohuanlin · 2025-04-18T17:21:08Z

dev/devicelab/lib/tasks/keyboard_hot_restart_test.dart

+  // This file is modified during the test and needs to be restored at the end.
+  final String oldContents = mainFile.readAsStringSync();
+  const String forceKeyboardOn = 'const bool forceKeyboard = true;';
+  const String forceKeyboardOff = 'const bool forceKeyboard = false;';


is it just a raw string to be displayed? why does it look like a piece of code?

I added a comment to clarify:

// When the test starts, the app forces the keyboard to be visible. // The test turns off this behavior by mutating the app's source code from // `forceKeyboardOn` to `forceKeyboardOff`. // See: //dev/integration_tests/keyboard_hot_restart/lib/main.dart

Let me know if you have follow-up questions!

wow changing the source code from the test, i've never seen this before. perhaps we can pass in an argument into the test instead.

A test argument wouldn't work as we need to change the app's behavior at the middle of the test: first it should make the keyboard visible, but after the hot restart it shouldn't. Let me know if you'd like to do a call to talk through this further :)

This seems very brittle. Is this an existing practice?

We have verify few tests that hot reload or hot restart an app. This appears to be an area of significant tech debt, but below are prior art I could find.

Hot mode test verifies that editing the framework's source code invalidates libraries:

flutter/dev/devicelab/lib/tasks/hot_mode_tests.dart

Lines 128 to 131 in b9abb56

flutterFrameworkSource.writeAsStringSync(

'${flutterFrameworkSource.readAsStringSync()}\n',

);

process.stdin.writeln('r');

Web dev mode test verifies that web hot reload works as expected:

flutter/dev/devicelab/lib/tasks/web_dev_mode_tests.dart

Lines 90 to 99 in b9abb56

appDartSource.writeAsStringSync(

appDartSource.readAsStringSync().replaceFirst(

"'Flutter Gallery'",

"'Updated Flutter Gallery'",

),

);

sw

..reset()

..start();

process.stdin.writeln('r');

dev/devicelab/lib/tasks/keyboard_hot_restart_test.dart

hellohuanlin · 2025-04-18T17:24:25Z

dev/integration_tests/keyboard_hot_restart/README.md

@@ -0,0 +1,5 @@
+# keyboard_hot_restart
+
+An app used to verify that the keyboard is not visible after a hot restart.


bonus: maybe also check system context menu is dismissed?

The presence of the SystemContextMenu widget is probably enough to indicate it's showing or not, if you can check for that. If not, maybe you could print something from the TextField's contextMenuBuilder.

Ahhh I didn't realize I could check for the context menu on the framework side, thanks for the pointers!

Justin and I talked offline. Unfortunately, the presence of the SystemContextMenu widget and TextField's contextMenuBuilder are not enough to detect whether the native context menu is visible. We don't have a good way to verify this native context menu from this "outside" test.

dev/integration_tests/keyboard_hot_restart/lib/main.dart

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterTextInputPlugin.mm

justinmc

LGTM but deferring to Huan for iOS expertise. Also I agree you should check for the presence of the system context menu in the test if you can.

Thanks for fixing this! It has annoyed me before. And thanks for writing a devicelab test for this.

dev/devicelab/lib/tasks/keyboard_hot_restart_test.dart

justinmc · 2025-04-18T17:55:18Z

dev/integration_tests/keyboard_hot_restart/README.md

@@ -0,0 +1,5 @@
+# keyboard_hot_restart
+
+An app used to verify that the keyboard is not visible after a hot restart.


The presence of the SystemContextMenu widget is probably enough to indicate it's showing or not, if you can check for that. If not, maybe you could print something from the TextField's contextMenuBuilder.

justinmc · 2025-04-18T17:58:09Z

engine/src/flutter/shell/platform/darwin/ios/platform_view_ios.mm

  }
  [owner_controller_.platformViewsController reset];
  [owner_controller_.restorationPlugin reset];
+  [owner_controller_.textInputPlugin reset];


This is all it took to fix it?

Yup. The fix took 30 seconds, the test took 3 days 😅

Classic haha.

hellohuanlin · 2025-04-18T23:50:31Z

engine/src/flutter/shell/platform/darwin/ios/platform_view_ios.mm

  }
  [owner_controller_.platformViewsController reset];
  [owner_controller_.restorationPlugin reset];
+  [owner_controller_.textInputPlugin reset];


just curious - the reset method of text input plugin was defined but never called before?

No reset is new, but it calls the existing hideTextInput method which is private and responds to the framework's TextInput.hide message.

hellohuanlin

Thank you for chatting offline about modifying the source file reasons.

The keyboard hot restart test does these steps: 1. It launches an app that forces the keyboard to be visible 2. It checks that the keyboard is visible by examining the app's logs 3. It updates the app to no longer force the keyboard to be visible and hot restarts the app 4. It checks that the keyboard is no longer visible by examining the app's logs Previously, the test app printed the keyboard status whenever the app rebuilt. The test would move on as soon as it saw a log that indicates the keyboard was in the expected state. However, since the app could log the keyboard's visibility _before_ the Dart VM was available, hot restart commands could be ignored (or at least, that's my theory from the DeviceLab logs). Now, the test app prints the keyboard status non-stop. The test now waits until the Dart VM is available before checking if the logs indicate the keyboard is open. Also, the test now waits until the hot restart has completed before checking if the keyboard is closed. In theory, this should ensure that hot restart does not happen until after the Dart VM is available. Follow-up to: #167013 Part of: #10713 ## 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, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord].  [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

The keyboard hot restart test listens to `flutter run` logs and then does an action. However, the test prints the `flutter run` log after the action. This results in confusing logs. For example: https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8716606099574306145/+/u/run_keyboard_hot_restart_ios/stdout ``` ═══════════╡ ••• Launch app and wait for keyboard to be visible ••• ╞═══════════ ... stdout: Installing and launching... 37.2s stdout: Syncing files to device swarming’s iPhone... ════╡ ••• Update the app to no longer force the keyboard to be visible ••• ╞════ ════════════════════════╡ ••• Hot restart the app ••• ╞═════════════════════════ ════════════╡ ••• Wait until the keyboard is no longer visible ••• ╞════════════ stdout: flutter: Keyboard is open ``` Here, the test waits until the keyboard is visible before moving onto the test's next step. However, the log that triggers this action (`flutter: Keyboard is open`) is printed after the action was taken (`Update the app to no longer force the keyboard to be visible` and `Wait until the keyboard is no longer visible`). This is confusing. Follow-up to: flutter#167013 Part of: flutter#10713

github-actions bot added platform-ios iOS applications specifically engine flutter/engine related. See also e: labels. team-ios Owned by iOS platform team labels Apr 11, 2025

hellohuanlin reviewed Apr 11, 2025

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loic-sharma force-pushed the ios_hide_keyboard branch from 41706e9 to 5861980 Compare April 16, 2025 19:27

[iOS] Hide keyboard on hot restart

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loic-sharma force-pushed the ios_hide_keyboard branch from 5861980 to 01063d3 Compare April 16, 2025 20:29

loic-sharma marked this pull request as ready for review April 16, 2025 22:03

loic-sharma requested review from a team and matanlurey as code owners April 16, 2025 22:03

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dev/devicelab/lib/tasks/keyboard_hot_restart_test.dart Outdated Show resolved Hide resolved

Update dev/devicelab/lib/tasks/keyboard_hot_restart_test.dart

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loic-sharma added 3 commits April 18, 2025 11:26

Feedback

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Feedback

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Fix avoid_print

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hellohuanlin reviewed Apr 18, 2025

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Add comment as to why we cannot use XCUITest

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Merged via the queue into flutter:master with commit 08a59c2 Apr 22, 2025
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Roll Flutter from cfb887cd5f41 to 2ffcab0a184a (34 revisions) flutter/packages#9136

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08a59c280 [iOS] Hide keyboard on hot restart (flutter/flutter#167013)

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08a59c280 [iOS] Hide keyboard on hot restart (flutter/flutter#167013)

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08a59c280 [iOS] Hide keyboard on hot restart (flutter/flutter#167013)

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08a59c280 [iOS] Hide keyboard on hot restart (flutter/flutter#167013)

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loic-sharma mentioned this pull request May 8, 2025

Fix keyboard_hot_restart_ios flakes #168518

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08a59c280 [iOS] Hide keyboard on hot restart (flutter/flutter#167013)

7ef99d0

	flutterFrameworkSource.writeAsStringSync(
	'${flutterFrameworkSource.readAsStringSync()}\n',
	);
	process.stdin.writeln('r');

	appDartSource.writeAsStringSync(
	appDartSource.readAsStringSync().replaceFirst(
	"'Flutter Gallery'",
	"'Updated Flutter Gallery'",
	),
	);
	sw
	..reset()
	..start();
	process.stdin.writeln('r');

		@@ -0,0 +1,5 @@
		# keyboard_hot_restart

		An app used to verify that the keyboard is not visible after a hot restart.

[iOS] Hide keyboard on hot restart #167013

[iOS] Hide keyboard on hot restart #167013

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loic-sharma commented Apr 11, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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loic-sharma commented Apr 11, 2025 •

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