flutter修改Inherited TextEdit OnChanged

Question

如何创建继承 TextField 小部件的类并覆盖 OnChanged 事件？

当用户打字时，我需要在我的应用程序中重置全局计时器，我想在自定义小部件中执行此操作并通过应用程序使用它。

类似的东西

  @override 
  OnChanged() {
    resetTimer();
    if (!widget.OnChanged) {//call OnChanged if is set}
  }

Answer 1

为了能够将我的自定义行为添加到 OnChanged，我必须在我的自定义小部件上“公开”祖先事件。它正在工作，我可以继续创建文本编辑，而无需在每个实例中将计时器调用添加到 OnChanged。

class CustomTextField extends TextField {
  const CustomTextField({
    Key? key,
    TextEditingController? controller,
    InputDecoration decoration = const InputDecoration(),
    TextInputType? keyboardType,
    TextAlign textAlign = TextAlign.start,
    List<TextInputFormatter>? inputFormatters,
    GestureTapCallback? onTap,
    ValueChanged<String>? onChanged,
  }) : super(
          key: key,
          controller: controller,
          decoration: decoration,
          keyboardType: keyboardType,
          inputFormatters: inputFormatters,
          textAlign: textAlign,
          onTap: onTap,
          onChanged: onChanged,
        );

  @override
  State<CustomTextField> createState() => _CustomTextFieldState();
}

class _CustomTextFieldState extends State<CustomTextField> {
  @override
  Widget build(BuildContext context) {
    return TextField(
      controller: widget.controller,
      decoration: widget.decoration,
      keyboardType: widget.keyboardType,
      inputFormatters: widget.inputFormatters,
      textAlign: widget.textAlign,
      onTap: widget.onTap,
      onChanged: _handleTextChanged,
    );
  }

  void _handleTextChanged(String value) {
    startSessionTimer(); //my call to the timer :)
    if (widget.onChanged != null) {
      widget.onChanged;
    }
  }
}