我正在尝试使用 Counter 测试应用程序使用 BloC 库,但是当我使用对象来递增/递减计数器时,我的视图中出现了一些问题。
MyObject.MyProperty 递增或递减,但我的视图未刷新。为什么?
示例应用程序使用简单的 int 变量。
我的代码与对象:
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:bloc/bloc.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
void main() {
runApp(App());
}
class App extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: BlocProvider(
builder: (context) => CounterBloc(),
child: CounterPage(),
),
);
}
}
class TestTest{
int myProperty;
TestTest(){
myProperty = 0;
}
}
class CounterPage extends StatefulWidget {
@override
_CounterPageState createState() => _CounterPageState();
}
class _CounterPageState extends State<CounterPage> {
@override
Widget build(BuildContext context) {
final counterBloc = BlocProvider.of<CounterBloc>(context);
return Scaffold(
appBar: AppBar(title: Text('Counter')),
body: BlocBuilder<CounterBloc, TestTest>(
builder: (context, myClassTestTest) {
return Center(
child: Text(
'${myClassTestTest.myProperty}',
style: TextStyle(fontSize: 24.0),
),
);
},
),
floatingActionButton: Column(
crossAxisAlignment: CrossAxisAlignment.end,
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(vertical: 5.0),
child: FloatingActionButton(
child: Icon(Icons.add),
onPressed: () {
counterBloc.dispatch(CounterEvent.increment);
},
),
),
Padding(
padding: EdgeInsets.symmetric(vertical: 5.0),
child: FloatingActionButton(
child: Icon(Icons.remove),
onPressed: () {
counterBloc.dispatch(CounterEvent.decrement);
},
),
),
],
),
);
}
}
enum CounterEvent { increment, decrement }
class CounterBloc extends Bloc<CounterEvent, TestTest> {
@override
TestTest get initialState => TestTest();
@override
Stream<TestTest> mapEventToState(CounterEvent event) async* {
switch (event) {
case CounterEvent.decrement:
currentState.myProperty -= 1;
yield currentState;
break;
case CounterEvent.increment:
currentState.myProperty += 1;
yield currentState;
break;
}
}
}
如您所见,我对示例应用程序进行了一些编辑以添加我的课程TestTest
具有 int 属性myProperty
。当我单击按钮时,对象中的值会发生变化,但我的视图不会刷新。
我该如何解决这个问题?
我找到了一个解决方案来重新创建我的 TestTestmapEventToState
但仅仅为了更新属性而重新创建整个对象是很奇怪的......
谢谢