/
bloc_page.dart
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/
bloc_page.dart
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import 'package:bloc/bloc.dart';
import 'package:flutter/material.dart';
import 'package:flutter_app/bloc/color_bloc.dart';
import 'package:flutter_app/bloc/number_bloc.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
class BlocPage extends StatefulWidget {
@override
State<StatefulWidget> createState() => _BlocPageState();
}
class _BlocPageState extends State<BlocPage> {
// NumberBloc _numBloc = NumberBloc();
// ColorBloc _colorBloc = ColorBloc();
NumberBloc _numBloc;
ColorBloc _colorBloc;
// @override
// Widget build(BuildContext context) {
// return BlocProvider(
// create: (BuildContext context) => NumberBloc(),
// child: BlocBuilder<NumberBloc, int>(condition: (previousState, state) {
// print('BlocPage.condition->$previousState==$state');
// return state <= 30 ? true : false;
// }, builder: (context, count) {
// return Scaffold(
// appBar: AppBar(title: Text('Bloc Page')),
// body: Center(
// child: Column(
// mainAxisAlignment: MainAxisAlignment.center,
// children: <Widget>[
// Text('当 Number > 30 时，不进行变更',
// style: TextStyle(fontSize: 20.0, color: Colors.blue)),
// SizedBox(height: 20.0),
// Text(
// '当前 Number = ${BlocProvider.of<NumberBloc>(context).state}',
// style: TextStyle(fontSize: 20.0, color: Colors.blue))
// ])),
// floatingActionButton: Column(
// crossAxisAlignment: CrossAxisAlignment.end,
// mainAxisAlignment: MainAxisAlignment.end,
// children: <Widget>[
// FloatingActionButton(
// heroTag: 'addTag',
// child: Icon(Icons.add),
// onPressed: () => BlocProvider.of<NumberBloc>(context)
// .add(NumberEvent.addEvent)),
// SizedBox(height: 20.0),
// FloatingActionButton(
// heroTag: 'removeTag',
// child: Icon(Icons.remove),
// onPressed: () => BlocProvider.of<NumberBloc>(context)
// .add(NumberEvent.removeEvent))
// ]));
// }));
// }
///======多个 Bloc 在 build() 方法外注册创建=======
// @override
// Widget build(BuildContext context) {
// return BlocListener<NumberBloc, int>(
// bloc: _numBloc,
// listener: (context, count) {
// print('BlocPage.listene->$count');
// },
// condition: (previousState, state) {
// print('BlocPage.BlocListener.condition->$previousState==$state');
// return state <= 20 ? true : false;
// },
// child: BlocBuilder<NumberBloc, int>(
// bloc: _numBloc,
// condition: (previousState, state) {
// print('BlocPage.condition->$previousState==$state');
// return state <= 30 ? true : false;
// },
// builder: (context, count) {
// return Scaffold(
// appBar: AppBar(
// title: Text('Bloc Page'),
// actions: <Widget>[_settingWid()]),
// body: Container(
// color: Colors.white.withGreen(200).withOpacity(0.4),
// child: _numberWid()),
// floatingActionButton: _floatingWid());
// }));
//}
///======多个 BlocProvider =======
@override
Widget build(BuildContext context) {
return BlocProvider(
create: (BuildContext context) => _numBloc = NumberBloc(),
child: BlocListener<NumberBloc, int>(
bloc: _numBloc,
listener: (context, state) =>
print('BlocListener--->NumberBloc--->$state'),
child: BlocBuilder<NumberBloc, int>(
bloc: _numBloc,
condition: (previousState, state) {
print('BlocPage.condition->$previousState==$state');
return state <= 30 ? true : false;
},
builder: (context, count) {
return BlocProvider(
create: (BuildContext context) =>
_colorBloc = ColorBloc(),
child: BlocListener<ColorBloc, Color>(
bloc: _colorBloc,
listener: (context, state) =>
print('BlocListener--->ColorBloc--->$state'),
child: BlocBuilder<ColorBloc, Color>(
bloc: _colorBloc,
builder: (context, color) {
return Scaffold(
appBar: AppBar(
title: Text('Bloc Page'),
actions: <Widget>[_settingWid()]),
body: Container(
color: _colorBloc.state,
child: _numberWid()),
floatingActionButton: _floatingWid());
})));
})));
}
///======MultiBlocProvider 方式=======
// @override
// Widget build(BuildContext context) {
// return MultiBlocProvider(
// providers: [
// BlocProvider(
// create: (BuildContext context) => _numBloc = NumberBloc()),
// BlocProvider(
// create: (BuildContext context) => _colorBloc = ColorBloc())
// ],
// child: MultiBlocListener(
// listeners: [
// BlocListener<NumberBloc, int>(listener: (context, state) {
// print('BlocListener--->NumberBloc--->$state');
// }),
// BlocListener<ColorBloc, Color>(listener: (context, state) {
// print('BlocListener--->ColorBloc--->$state');
// })
// ],
// child: BlocBuilder<NumberBloc, int>(
// bloc: _numBloc,
// condition: (previousState, state) {
// print('BlocPage.condition->$previousState==$state');
// return state <= 30 ? true : false;
// },
// builder: (context, count) {
// return BlocBuilder<ColorBloc, Color>(
// bloc: _colorBloc,
// builder: (context, color) {
// return Scaffold(
// appBar: AppBar(
// title: Text('Bloc Page'),
// actions: <Widget>[_settingWid()]),
// body: Container(
// color: _colorBloc.state, child: _numberWid()),
// floatingActionButton: _floatingWid());
// });
// })));
// }
_settingWid() {
return FlatButton(
onPressed: () => _colorBloc.add(ColorEvent()),
child: Icon(Icons.settings, color: Colors.white));
}
_numberWid() {
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'当 Number > 20 时，BlocListener 过滤 listener 监听，与 BlocBuilder 中过滤的状态无关',
style: TextStyle(fontSize: 20.0, color: Colors.red)),
SizedBox(height: 20.0),
Text('当 Number > 30 时，Number 不进行变更',
style: TextStyle(fontSize: 20.0, color: Colors.green)),
SizedBox(height: 20.0),
Text('当前 Number = ${_numBloc.state}',
style: TextStyle(fontSize: 20.0, color: Colors.blue))
]));
}
_floatingWid() {
return Column(
crossAxisAlignment: CrossAxisAlignment.end,
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
FloatingActionButton(
heroTag: 'addTag',
child: Icon(Icons.add),
onPressed: () => _numBloc.add(NumberEvent.addEvent)),
SizedBox(height: 20.0),
FloatingActionButton(
heroTag: 'removeTag',
child: Icon(Icons.remove),
onPressed: () => _numBloc.add(NumberEvent.removeEvent))
]);
}
}