Repository: flutter
Issue: CharacterActivator not working with hardware keyboard on iOS
Labels: a: text input,platform-ios,P2,team-ios,triaged-ios

## Steps to Reproduce

[`CharacterActivator`](https://api.flutter.dev/flutter/widgets/CharacterActivator-class.html) is not triggered in a Flutter app when using a hardware keyboard connected to an iOS device or simulator. It works on Android.

When testing on physical devices I used an MX Keys keyboard connected via Bluetooth. For the iOS simulator test, I used the built-in keyboard on the host machine.

1. Execute `flutter run` on the code sample <!-- (see "Code sample" section below) -->
2. Observe the text "Ask a question"
3. Hold down Shift and press the "/" key to produce the character "?"

**Expected results:**
Screen shows "Good question!" because `CharacterActivator` triggered.

**Actual results:**
On Android, it works. On iOS, the screen continues to show "Ask a question"

You can edit the code sample to try to detect other characters and it still doesn't work on iOS.

<details>
<summary>Code sample</summary>

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      and attach it below between the lines with the backticks.

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```dart
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _text = "Ask a question";

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        body: Center(
          child: CallbackShortcuts(
            bindings: {
              const CharacterActivator('?'): () {
                setState(() {
                  _text = "Good question!";
                });
              },
            },
            child: Focus(
              autofocus: true,
              child: Text(_text, style: const TextStyle(fontSize: 40)),
            ),
          ),
        ),
      ),
    );
  }
}
```

</details>

<details>
  <summary>Logs</summary>

<!--
      Run your application with `flutter run --verbose` and attach all the
      log output below between the lines with the backticks. If there is an
      exception, please see if the error message includes enough information
      to explain how to solve the issue.
-->

```
[  +57 ms] Successfully connected to service protocol: http://127.0.0.1:53908/
[  +26 ms] DevFS: Creating new filesystem on the device (null)
[  +22 ms] DevFS: Created new filesystem on the device
(file:///private/var/mobile/Containers/Data/Application/BE9A4251-21C9-4C17-91C4-E11CE48A7DDF/tmp/hardware_keyboard_testjZQdq7/hardware_keyboard_test/)
[   +2 ms] Updating assets
[  +66 ms] Syncing files to device iPhone...
[   +1 ms] <- reset
[        ] Compiling dart to kernel with 0 updated files
[        ] Processing bundle.
[   +1 ms] <- recompile package:hardware_keyboard_test/main.dart 1938f5a0-62cb-4a62-9da0-6d8bb6d4313a
[        ] <- 1938f5a0-62cb-4a62-9da0-6d8bb6d4313a
[   +1 ms] Bundle processing done.
[  +54 ms] Updating files.
[        ] DevFS: Sync finished
[   +1 ms] Syncing files to device iPhone... (completed in 59ms)
[        ] Synced 0.0MB.
[   +2 ms] <- accept
[  +18 ms] Connected to _flutterView/0x139820e20.
[   +2 ms] Flutter run key commands.
[   +1 ms] r Hot reload. 🔥🔥🔥
[        ] R Hot restart.
[        ] h List all available interactive commands.
[        ] d Detach (terminate "flutter run" but leave application running).
[        ] c Clear the screen
[        ] q Quit (terminate the application on the device).
[        ] 💪 Running with sound null safety 💪
[        ] An Observatory debugger and profiler on iPhone is available at: http://127.0.0.1:53913/mpJJYIx8pS4=/
[  +46 ms] The Flutter DevTools debugger and profiler on iPhone is available at: http://127.0.0.1:9100?uri=http://127.0.0.1:53913/mpJJYIx8pS4=/

```

<!--
     Run `flutter analyze` and attach any output of that command below.
     If there are any analysis errors, try resolving them before filing this issue.
-->

```
Analyzing hardware_keyboard_test...                                     
No issues found! (ran in 1.8s)
```

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

Flutter doctor shows an issue with IntelliJ but I don't think it's related. I'm launching using the command line.

```
[✓] Flutter (Channel stable, 2.10.2, on macOS 12.2 21D49 darwin-x64, locale en-US)
    • Flutter version 2.10.2 at /Users/jackson/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 097d3313d8 (9 days ago), 2022-02-18 19:33:08 -0600
    • Engine revision a83ed0e5e3
    • Dart version 2.16.1
    • DevTools version 2.9.2

[✓] Android toolchain - develop for Android devices (Android SDK version 32.0.0)
    • Android SDK at /Users/jackson/Library/Android/sdk
    • Platform android-32, build-tools 32.0.0
    • ANDROID_SDK_ROOT = /home/jackson/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7281165)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 13.2.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • CocoaPods version 1.11.2

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2020.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7281165)

[☠] IntelliJ IDEA Community Edition (the doctor check crashed)
    ✗ Due to an error, the doctor check did not complete. If the error message below is not helpful, please let us know about this issue at
      https://github.com/flutter/flutter/issues.
    ✗ FormatException: Unexpected extension byte (at offset 5)
    • #0      _Utf8Decoder.convertSingle (dart:convert-patch/convert_patch.dart:1789:7)
      #1      Utf8Decoder.convert (dart:convert/utf.dart:351:42)
      #2      InputStream.readString (package:archive/src/util/input_stream.dart:207:30)
      #3      new ZipDirectory.read (package:archive/src/zip/zip_directory.dart:40:30)
      #4      ZipDecoder.decodeBuffer (package:archive/src/zip_decoder.dart:19:30)
      #5      ZipDecoder.decodeBytes (package:archive/src/zip_decoder.dart:14:12)
      #6      IntelliJPlugins._findPluginXml (package:flutter_tools/src/intellij/intellij.dart:130:44)
      #7      IntelliJPlugins._readPackageVersion (package:flutter_tools/src/intellij/intellij.dart:141:40)
      #8      IntelliJPlugins.validatePackage (package:flutter_tools/src/intellij/intellij.dart:63:35)
      #9      IntelliJValidator.validate (package:flutter_tools/src/intellij/intellij_validator.dart:103:15)
      #10     asyncGuard.<anonymous closure> (package:flutter_tools/src/base/async_guard.dart:111:32)
      #11     asyncGuard.<anonymous closure> (package:flutter_tools/src/base/async_guard.dart:109:18)
      #12     _rootRun (dart:async/zone.dart:1426:13)
      #13     _CustomZone.run (dart:async/zone.dart:1328:19)
      #14     _runZoned (dart:async/zone.dart:1861:10)
      #15     runZonedGuarded (dart:async/zone.dart:1849:12)
      #16     runZoned (dart:async/zone.dart:1780:12)
      #17     asyncGuard (package:flutter_tools/src/base/async_guard.dart:109:3)
      #18     Doctor.startValidatorTasks (package:flutter_tools/src/doctor.dart:205:9)
      #19     Doctor.diagnose (package:flutter_tools/src/doctor.dart:309:47)
      #20     DoctorCommand.runCommand (package:flutter_tools/src/commands/doctor.dart:50:48)
      #21     FlutterCommand.verifyThenRunCommand (package:flutter_tools/src/runner/flutter_command.dart:1320:12)
      <asynchronous suspension>
      #22     FlutterCommand.run.<anonymous closure> (package:flutter_tools/src/runner/flutter_command.dart:1161:27)
      <asynchronous suspension>
      #23     AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:150:19)
      <asynchronous suspension>
      #24     CommandRunner.runCommand (package:args/command_runner.dart:209:13)
      <asynchronous suspension>
      #25     FlutterCommandRunner.runCommand.<anonymous closure> (package:flutter_tools/src/runner/flutter_command_runner.dart:281:9)
      <asynchronous suspension>
      #26     AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:150:19)
      <asynchronous suspension>
      #27     FlutterCommandRunner.runCommand (package:flutter_tools/src/runner/flutter_command_runner.dart:229:5)
      <asynchronous suspension>
      #28     run.<anonymous closure>.<anonymous closure> (package:flutter_tools/runner.dart:62:9)
      <asynchronous suspension>
      #29     AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:150:19)
      <asynchronous suspension>
      #30     main (package:flutter_tools/executable.dart:94:3)
      <asynchronous suspension>


[✓] Connected device (5 available)
    • SM A125U (mobile)      • R58R85BBCAV                          • android-arm64  • Android 11 (API 30)
    • iPhone (mobile)        • 00008101-001155042188801E            • ios            • iOS 15.1 19B74
    • iPhone 12 Pro (mobile) • 132369FE-696E-42C9-B0F4-EE1A24E377FC • ios            • com.apple.CoreSimulator.SimRuntime.iOS-15-2 (simulator)
    • macOS (desktop)        • macos                                • darwin-x64     • macOS 12.2 21D49 darwin-x64
    • Chrome (web)           • chrome                               • web-javascript • Google Chrome 98.0.4758.109

[✓] HTTP Host Availability
    • All required HTTP hosts are available

! Doctor found issues in 1 category.
```

</details>


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Possibly related issue: https://github.com/flutter/flutter/issues/99252