如何为futurebuilder调用setState

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

class _MyWidgetState extends State<MyWidget> {
  Future<String> fetchData() async {
    await Future.delayed(Duration(seconds: 2));
    return "Data loaded successfully";
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: fetchData(),
      builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
        if (snapshot.connectionState == ConnectionState.waiting) {
          // 显示连接中的UI
          return CircularProgressIndicator();
        } else if (snapshot.connectionState == ConnectionState.done) {
          if (snapshot.hasError) {
            // 显示错误的UI
            return Text('Error: ${snapshot.error}');
          } else {
            // 显示数据加载成功的UI
            return Column(
              children: [
                Text('Data: ${snapshot.data}'),
                ElevatedButton(
                  onPressed: () {
                    setState(() {
                      // 更新状态，触发UI重建
                    });
                  },
                  child: Text('Update UI'),
                ),
              ],
            );
          }
        } else {
          // 其他情况...
          return Container();
        }
      },
    );
  }
}