Text fields' values do not get trimmed correctly when `textDirection: TextDirection.rtl`

[HasanAlyazidi]

Steps to Reproduce

1. Run flutter create bug.
2. Create a simple widget
3. Add a TextFormField or TextField widget with textDirection: TextDirection.rtl
4. Print trimmed value inside onChanged

Expected results:
I expect when i call trim() on the value of the text field returned from onChanged or controller.text, it should get trimmed.

when i type " str ", "str ", " str" it should remove the leading and trailing whitespaces and return: 'str'

Actual results:
It does not get trimmed correctly if textDirection: TextDirection.rtl, but, it works just fine if textDirection: TextDirection.ltr.

Here is a working demo of the bug:
https://dartpad.dev/b6130da3c610e01d4cc2ddf0ab278d3e

Logs

No exceptions

Analyzing bug...
No issues found! (ran in 3.4s)

[✓] Flutter (Channel stable, 1.20.4, on Microsoft Windows [Version 10.0.19041.508], locale en-US)
• Flutter version 1.20.4 at X:\Development\Configurations\flutter
• Framework revision fba99f6 (4 weeks ago), 2020-09-14 15:32:52 -0700
• Engine revision d1bc06f032
• Dart version 2.9.2

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
• Android SDK at X:\Development\Configurations\android\sdk
• Platform android-30, build-tools 30.0.2
• ANDROID_HOME = X:\Development\Configurations\android\sdk
• ANDROID_SDK_ROOT = X:\Development\Configurations\android\sdk
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
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• Flutter plugin version 48.1.2
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• VS Code at C:\Users\USR\AppData\Local\Programs\Microsoft VS Code
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[✓] Connected device (1 available)
• Android SDK built for x86 (mobile) • emulator-5554 • android-x86 • Android 10 (API 29) (emulator)

• No issues found!

[darshankawar]

flutter doctor -v

[✓] Flutter (Channel stable, 1.22.1, on Mac OS X 10.15.4 19E2269, locale en-IN)
    • Flutter version 1.22.1 at /Users/dhs/documents/Fluttersdk/flutter
    • Framework revision f30b7f4db9 (6 days ago), 2020-10-08 10:06:30 -0700
    • Engine revision 75bef9f6c8
    • Dart version 2.10.1

 
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
    • Android SDK at /Users/dhs/Library/Android/sdk
    • Platform android-30, build-tools 30.0.0
    • Java binary at: /Applications/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 12.0.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.0.1, Build version 12A7300
    • CocoaPods version 1.9.3

[✓] Android Studio (version 4.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 46.0.2
    • Dart plugin version 193.7361
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.49.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.11.0

[✓] Connected device (1 available)
    • SM A260G (mobile) • 5200763ebcfa861f • android-arm • Android 8.1.0 (API
      27)

• No issues found!

TextInput: (this ‎is ‎not ‎working ‎ ‎ ‎ ‎ ‎ ‎ ‎)
TextDirection.ltr: (around)
TextDirection.ltr: (around)

[LongCatIsLooong]

I think the directionality markers we inserted prevented trim from removing the surrounding whitespaces. \cc @GaryQian .

[AlaaEldeenYsr]

  String trim(String string) {
    assert(string != null);
    final stringList = string.characters.toList();
    final whitespaces = ['8206', '8207', '32'];
    while (whitespaces.contains(stringList.last.runes.join())) stringList.removeLast();
    while (whitespaces.contains(stringList.first.runes.join())) stringList.remove(stringList.first);
    return stringList.join();
  }

[github-actions]

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