Flutter StreamBuilder 的用法

Flutter StreamBuilder 的用法 异步流操作

/// Flutter code sample for StreamBuilder

// This sample shows a [StreamBuilder] that listens to a Stream that emits bids
// for an auction. Every time the StreamBuilder receives a bid from the Stream,
// it will display the price of the bid below an icon. If the Stream emits an
// error, the error is displayed below an error icon. When the Stream finishes
// emitting bids, the final price is displayed.

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

/// This is the main application widget.
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: _title,
      home: MyStatefulWidget(),
    );
  }
}

/// This is the stateful widget that the main application instantiates.
class MyStatefulWidget extends Stat