如果StreamBuilder获取null，则在颤动中显示不同窗口小部件

import 'package:flutter/material.dart';
import 'package:shimmer/shimmer.dart';

class MyWidget extends StatelessWidget {
  final Stream<String> dataStream; // 假设数据流的类型为String

  MyWidget({required this.dataStream});

  @override
  Widget build(BuildContext context) {
    return StreamBuilder<String>(
      stream: dataStream,
      initialData: null, // 设置初始值为null
      builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
        if (snapshot.hasData) {
          // 数据加载完成，显示实际内容
          return Text(snapshot.data!);
        } else if (snapshot.hasError) {
          // 数据加载出错，显示错误信息
          return Text('Error: ${snapshot.error}');
        } else {
          // 数据还未加载完成，显示颤动效果
          return Shimmer.fromColors(
            baseColor: Colors.grey[300]!,
            highlightColor: Colors.grey[100]!,
            child: Container(
              width: 200,
              height: 20,
              color: Colors.white,
            ),
          );
        }
      },
    );
  }
}