bloc

示例分为两个文件

 

main.dart

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return InheritedData(
      data:ShareData(),
      child: Scaffold(
        appBar: AppBar(title: Text('blocDemo'),),
        body: ActionButton(),
        floatingActionButton: FloatingButton(),
      ),
    );
  }
}



bloc.dart

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

class ActionButton extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    ShareData _shareData = InheritedData.of(context).data;
    return Center(
      child: StreamBuilder(
        stream: _shareData._streamControllerForBuilder.stream,
        builder: (context,snapshot){
          return  ActionChip(
            label: Text('${snapshot.data}'),
            onPressed: () {
              _shareData._streamControllerSink.add(_shareData.index);
              _shareData.index++;

            },
          );
        },
      ),
    );
  }
}



class FloatingButton extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    ShareData _shareData = InheritedData.of(context).data;
    return FloatingActionButton(
      child: Icon(Icons.add_alarm),
      onPressed: () {
        _shareData._streamControllerSink.add(_shareData.index);
        _shareData.index++;
      },
    );
  }
}

class ShareData {
  int index = 0;
  StreamController _streamController = StreamController.broadcast();
  StreamSink get _streamControllerSink => _streamController.sink;

  StreamController _streamControllerForBuilder = StreamController();
  StreamSink get builderSink => _streamControllerForBuilder.sink;
  ShareData() {
    _streamController.stream.listen(onData);
  }
  onData(data) {
    builderSink.add(data);
  }

  void dispose() {
    _streamController.close();
    _streamControllerForBuilder.close();
  }
} //共享数据均在该类中定义

class InheritedData extends InheritedWidget {
  final Widget child;
  final ShareData data;

  InheritedData({this.data, this.child}) : super(child: child);

  static InheritedData of(BuildContext context) {
    return context.inheritFromWidgetOfExactType(InheritedData);
  }

  @override
  bool updateShouldNotify(InheritedData old) {
    return old.data != data;
  }
}