showAutocorrectionPromptRect method added to TextInputClient

A new method,void showAutocorrectionPromptRect(int start, int end), was added to the TextInputClient interface.

In order to display the iOS autocorrection highlight, the iOS text input plugin needed a way to inform the Flutter framework of the highlight's start and end position.

A new method, void showAutocorrectionPromptRect(int start, int end), was added to the TextInputClient interface. iOS calls this method when it finds a new potential autocorrect candidate in the current user input, or when the range of a previously highlighted candidate changes.

If your application doesn't implement or subclass TextInputClient, no migration is needed. If your application doesn't target iOS, or the class that implemented the textInputClient interface doesn't support autocorrect, you only need to add an empty implementation for the new method:

class CustomTextInputClient implements TextInputClient {
  void showAutocorrectionPromptRect(int start, int end) {}
}

Otherwise, if your app targets iOS and supports autocorrect on iOS, we recommend that you add a sensible implementation of void showAutocorrectionPromptRect(int start, int end) to your TextInputClient subclass.

Code after migration:

// Assume your `TextInputClient` is a `State` subclass, and it has a variable 
// `_currentPromptRectRange` that controls the autocorrection highlight.
class CustomTextInputClient extends State<...> implements TextInputClient {
  @override
  void updateEditingValue(TextEditingValue value) {
    // When the text changes, the highlight needs to be dismissed.
    if (value.text != _value.text) {
      setState(() {
        _currentPromptRectRange = null;
      });
    }
  }

  void _handleFocusChanged() {
    // When this text input loses focus, the autocorrection highlight needs
    // to be dismissed.
    if (!_hasFocus) {
      setState(() {
        _currentPromptRectRange = null;
      });
    }
  }

  @override
  void showAutocorrectionPromptRect(int start, int end) {
    // Updates the range of the highlight, as iOS requested.
    // This method isn't called when iOS decides to
    // dismiss the highlight.
    setState(() {
      _currentPromptRectRange = TextRange(start: start, end: end);
    });
  }
}

In stable release: 1.20

API documentation:

• TextInputClient

Relevant issue:

• Issue 12920

Relevant PR:

• iOS UITextInput autocorrection prompt

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