Flutter小部件上的印记或跟踪

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  final GlobalKey<_MyChildWidgetState> _childKey = GlobalKey();

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        MyChildWidget(key: _childKey),
        RaisedButton(
          child: Text('Rebuild Child Widget'),
          onPressed: () {
            setState(() {
              // 通过印记或跟踪重新构建特定的小部件
              _childKey.currentState.rebuild();
            });
          },
        ),
      ],
    );
  }
}

class MyChildWidget extends StatefulWidget {
  MyChildWidget({Key key}) : super(key: key);

  @override
  _MyChildWidgetState createState() => _MyChildWidgetState();
}

class _MyChildWidgetState extends State<MyChildWidget> {
  int _counter = 0;

  void rebuild() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Text('Counter: $_counter');
  }
}