尝试在flutter中使用widget.string访问字符串时获取空值

class ParentWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChildWidget(string: 'Hello, World!');
  }
}

class ChildWidget extends StatelessWidget {
  final String string;

  ChildWidget({required this.string});

  @override
  Widget build(BuildContext context) {
    return Text(string ?? 'Default Value');
  }
}

final key = GlobalKey();

class ParentWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(key: key, child: ChildWidget());
  }
}

class ChildWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final parentWidget = key.currentContext!.findAncestorWidgetOfExactType<ParentWidget>();
    return Text(parentWidget?.string ?? 'Default Value');
  }
}

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

class _MyWidgetState extends State<MyWidget> {
  String? _string;

  @override
  void initState() {
    super.initState();
    // 确保在组件完全初始化之后再设置_string
    _string = 'Hello, World!';
  }

  @override
  Widget build(BuildContext context) {
    return Text(_string ?? 'Default Value');
  }
}