TextInput onChangeText is firing at wrong time when type with Chinese input keyboard in iOS

[hermanho]

Description

TextInput onChangeText is firing at wrong time. Here is the gif to show the problem.

I am typing the Chinese wording "你好" with a Chinese input keyboard in iOS.

1. The char "你" is inputted by the code "人火".
2. I type with the code "人火" and these two codes are highlighted in grey in the textbox. The input method is still not completed yet. The code "人火" should not be considered as a text change event. However, onChangeText is triggered.
   
3. After I select the char "你" in Chinese input keyboard, onChangeText is triggered twice.
   

React Native version:

System:
    OS: macOS 11.0.1
    CPU: (8) x64 Intel(R) Core(TM) i7-8557U CPU @ 1.70GHz
    Memory: 751.11 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 14.15.1 - /usr/local/bin/node
    Yarn: Not Found
    npm: 6.14.8 - /usr/local/bin/npm
    Watchman: 4.9.0 - /usr/local/bin/watchman
  Managers:
    CocoaPods: 1.10.0 - /usr/local/bin/pod
  SDKs:
    iOS SDK:
      Platforms: iOS 14.2, DriverKit 20.0, macOS 11.0, tvOS 14.2, watchOS 7.1
    Android SDK: Not Found
  IDEs:
    Android Studio: 4.1 AI-201.8743.12.41.6953283
    Xcode: 12.2/12B45b - /usr/bin/xcodebuild
  Languages:
    Java: Not Found
    Python: 2.7.16 - /usr/bin/python
  npmPackages:
    @react-native-community/cli: Not Found
    react: 16.13.1 => 16.13.1 
    react-native: https://github.com/expo/react-native/archive/sdk-40.0.1.tar.gz => 0.63.2 
    react-native-macos: Not Found
  npmGlobalPackages:
    *react-native*: Not Found

Steps To Reproduce

Provide a detailed list of steps that reproduce the issue.

1. Open https://snack.expo.io/@hkhermanho/textinput-with-chinese
2. Type any Chinese characters with Chinese input method

Expected Results

onChangeText should not be fire before the input method is done. It should be fired 2 times for 2 Chinese characters instead of 8 times.

Snack, code example, screenshot, or link to a repository:

https://snack.expo.io/@hkhermanho/textinput-with-chinese

[rnike]

This can be fixed by applying the following diff to react-native source code

diff --git a/Libraries/Text/TextInput/RCTBackedTextInputDelegateAdapter.m b/Libraries/Text/TextInput/RCTBackedTextInputDelegateAdapter.m
--- a/Libraries/Text/TextInput/RCTBackedTextInputDelegateAdapter.m
+++ b/Libraries/Text/TextInput/RCTBackedTextInputDelegateAdapter.m
@@ -107,6 +107,12 @@ - (BOOL)textFieldShouldReturn:(__unused UITextField *)textField

 - (void)textFieldDidChange
 {
+  UITextRange *markedTextRange = _backedTextInputView.markedTextRange;
+
+  if (markedTextRange != nil && !markedTextRange.empty) {
+      return;
+  }
+
   _textDidChangeIsComing = NO;
   [_backedTextInputView.textInputDelegate textInputDidChange];

the result will be

after_applied.mov

but we will not able to handle the "ongoing text" ( ㄋㄧ ˇㄏㄠˇ in my video) anymore.

So I tried using onSelectionChange to see if we can handle onTextChanged only if no text selected, but react-native doesn't consider the "ongoing text" as a text selection, see the image below, the selection start,end should be 0,3 but 3,3

---

Seems like the "ongoing text" is not currently well handled by react-native, I'll stick to the diff solution mentioned above and make a pull request.

[urtheone]

still happen in 0.64.2

[ouabing]

Seems like @rnike 's workaround doesn't work any more in RN 0.67.4. Does anyone figure out how to solve this problem? I'm not an iOS developer but would like to help test.

[rnike]

@ouabing no my workaround is still working on react-native 0.68.2

sc.mov

I think it's just because my pr #31376 is still opening and not merged

[github-actions]

This issue is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[hermanho]

Not stale. The pr #31376 is still opening and not merged