Future<void>多次返回小部件构建

Future<void> fetchData() async {
  // 模拟耗时操作
  await Future.delayed(Duration(seconds: 2));
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return FutureBuilder<void>(
      future: fetchData(),
      builder: (BuildContext context, AsyncSnapshot<void> snapshot) {
        if (snapshot.connectionState == ConnectionState.waiting) {
          // 显示加载指示器
          return CircularProgressIndicator();
        } else if (snapshot.hasError) {
          // 显示错误信息
          return Text('Error: ${snapshot.error}');
        } else {
          // 显示数据
          return Text('Data loaded successfully');
        }
      },
    );
  }
}