示例分為兩個文件

?

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();
}
} //共享數據均在該類中定義

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;
}
}

轉載于:https://www.cnblogs.com/braveheart007/p/10980877.html

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