tut 11 komplett

tut11komplett.dart

import 'package:flutter/material.dart';
import 'zaehler_bloc.dart';
import 'zaehler_ereignis.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final _bloc = ZaehlerBloc();

  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child:StreamBuilder(
          stream: _bloc.zaheler,
          initialData: 0,
          builder: (BuildContext context, AsyncSnapshot<int> snapshot){
            return Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '${snapshot.data}',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        );
          },
        ),
      ),
      floatingActionButton: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          FloatingActionButton(
            onPressed: ()=>_bloc.zaehlerEventSink.add(AdditionsEreignis()),
            tooltip: 'Increment',
            child: Icon(Icons.add),
          ),
          SizedBox(width: 10.0,),
          FloatingActionButton(
            onPressed: ()=>_bloc.zaehlerEventSink.add(SubtraktionsEreignis()),
            tooltip: 'Decrement',
            child: Icon(Icons.remove),
          ),
        ],
      ),
    );
  }
 @override
  void dispose() {
    super.dispose();
    _bloc.dispose();
  }
}

tut11komplett2.dart

  import 'dart:async';
import 'zaehler_ereignis.dart';

class ZaehlerBloc {
  int _zaehler = 0;

  final _zaehlerStateController = StreamController<int>();

  StreamSink<int> get _inZaehler =>
      _zaehlerStateController.sink; //  die Variable ist privat

  Stream<int> get zaheler =>
      _zaehlerStateController.stream; // die Variable  ist öffentlich

  final _zaehlerEventController = StreamController<ZaehlerEreignis>();

  Sink<ZaehlerEreignis> get zaehlerEventSink => _zaehlerEventController.sink;

  ZaehlerBloc() {
    _zaehlerEventController.stream.listen(_mapEventToState);
  }
  void _mapEventToState(ZaehlerEreignis event) {
    if (event is AdditionsEreignis)
      _zaehler++;
    else
      _zaehler--;
    _inZaehler.add(_zaehler);
  }

  void dispose() {
    _zaehlerStateController.close();
    _zaehlerEventController.close();
  }
}

tut11komplett3.dart

abstract class ZaehlerEreignis {
  
}
class AdditionsEreignis extends ZaehlerEreignis {
  
}

class SubtraktionsEreignis extends ZaehlerEreignis {
  
}