在一个StreamBuilder中使用2个不同的流

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  final StreamController<int> streamController1 = StreamController<int>();
  final StreamController<String> streamController2 = StreamController<String>();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('StreamBuilder Example'),
        ),
        body: Center(
          child: StreamBuilder<int>(
            stream: streamController1.stream,
            builder: (BuildContext context, AsyncSnapshot<int> snapshot1) {
              return StreamBuilder<String>(
                stream: streamController2.stream,
                builder: (BuildContext context, AsyncSnapshot<String> snapshot2) {
                  if (snapshot1.hasData && snapshot2.hasData) {
                    return Text('Stream 1: ${snapshot1.data}\nStream 2: ${snapshot2.data}');
                  } else {
                    return Text('Waiting for data...');
                  }
                },
              );
            },
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () {
            streamController1.add(42);
            streamController2.add('Hello');
          },
          child: Icon(Icons.add),
        ),
      ),
    );
  }
}