如何同时使用FutureBuilder和setState方法？(颤动)

FutureBuilder(
  future: _fetchData(), // 异步操作的Future对象
  builder: (BuildContext context, AsyncSnapshot snapshot) {
    if (snapshot.connectionState == ConnectionState.waiting) {
      return CircularProgressIndicator(); // 加载中的UI展示
    } else if (snapshot.hasError) {
      return Text('Error: ${snapshot.error}'); // 加载失败的UI展示
    } else {
      return Text('Data: ${snapshot.data}'); // 加载成功的UI展示
    }
  },
)

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

class _MyWidgetState extends State<MyWidget> {
  String _data;

  Future<void> _fetchData() async {
    // 异步加载数据的逻辑
    // ...

    setState(() {
      _data = fetchedData; // 更新状态变量
    });
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _fetchData(),
      builder: (BuildContext context, AsyncSnapshot snapshot) {
        // ...
      },
    );
  }
}