Flutter 如何使用flatterbloc构建一个文本字段,在用户输入时将其值更新到另一个小部件?
我正在寻找一些接近谷歌字体的东西 我创建了一个这样工作的示例演示Flutter 如何使用flatterbloc构建一个文本字段,在用户输入时将其值更新到另一个小部件?,flutter,Flutter,我正在寻找一些接近谷歌字体的东西 我创建了一个这样工作的示例演示 import 'package:flutter/material.dart'; import 'package:flutter_bloc/flutter_bloc.dart'; void main() { // for bloc transition trace //BlocSupervisor.delegate = SimpleBlocDelegate(); runApp(MyApp()); } class My
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
void main() {
// for bloc transition trace
//BlocSupervisor.delegate = SimpleBlocDelegate();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return BlocProvider<TextUpdateBloc>(
create: (context) => TextUpdateBloc(),
child: MaterialApp(
home: Scaffold(body: DeleteWidget()),
),
);
}
}
class TextInputState {}
class TextInputInitState extends TextInputState {
String text;
TextInputInitState({this.text});
}
class TextInputDataChange extends TextInputState {
String text;
TextInputDataChange({this.text});
}
class TextEvents {}
class TextInit extends TextEvents {}
class TextChange extends TextEvents {
final String data;
TextChange({@required this.data});
}
class TextUpdateBloc extends Bloc<TextEvents, TextInputState> {
@override
get initialState => TextInputInitState(text: "");
@override
Stream<TextInputState> mapEventToState(event) async* {
if (event is TextInit) {
yield TextInputInitState(text: "");
} else if (event is TextChange) {
yield TextInputInitState(text: event.data);
}
}
}
class DeleteWidget extends StatelessWidget {
const DeleteWidget({Key key}) : super(key: key);
@override
Widget build(BuildContext context) {
final TextUpdateBloc counterBloc = BlocProvider.of<TextUpdateBloc>(context);
return Scaffold(
appBar: AppBar(
title: Text('test app'),
),
body: Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
TextFormField(
onChanged: (value) => counterBloc.add(TextChange(data: value)),
),
Container(
child: BlocBuilder<TextUpdateBloc, TextInputState>(
builder: (context, state) {
if (state is TextInputInitState) {
return Text(state.text.toString());
} else if (state is TextInputDataChange) {
return Text(state.text.toString());
} else {
return Text("something worng");
}
},
),
),
],
),
),
);
}
}
导入“包装:颤振/材料.省道”;
进口“包装:颤振团/颤振团.飞镖”;
void main(){
//对于块过渡跟踪
//BlocSupervisor.delegate=SimpleBlocDelegate();
runApp(MyApp());
}
类MyApp扩展了无状态小部件{
@凌驾
小部件构建(构建上下文){
返回BlocProvider(
create:(context)=>TextUpdateBloc(),
孩子:MaterialApp(
主页:Scaffold(主体:DeleteWidget()),
),
);
}
}
类TextInputState{}
类TextInputItState扩展了TextInputState{
字符串文本;
TextInputItState({this.text});
}
类TextInputDataChange扩展了TextInputState{
字符串文本;
TextInputDataChange({this.text});
}
类TextEvents{}
类TextInit扩展了TextEvents{}
类TextChange扩展了TextEvents{
最终字符串数据;
TextChange({@required this.data});
}
类TextUpdateBloc扩展了Bloc{
@凌驾
get initialState=>TextInputItState(文本:“”);
@凌驾
流mapEventToState(事件)异步*{
if(事件为TextInit){
产生文本输入状态(文本:“”);
}else if(事件为TextChange){
生成TextInputitState(文本:event.data);
}
}
}
类DeleteWidget扩展了无状态Widget{
constdeleteWidget({Key}):超级(Key:Key);
@凌驾
小部件构建(构建上下文){
final TextUpdateBloc counterBloc=BlocProvider.of(上下文);
返回脚手架(
appBar:appBar(
标题:文本(“测试应用程序”),
),
主体:容器(
子:列(
mainAxisAlignment:mainAxisAlignment.center,
crossAxisAlignment:crossAxisAlignment.center,
儿童:[
TextFormField(
onChanged:(value)=>counterBloc.add(TextChange(数据:value)),
),
容器(
孩子:BlocBuilder(
生成器:(上下文、状态){
如果(状态为TextInputItState){
返回文本(state.Text.toString());
}else if(状态为TextInputDataChange){
返回文本(state.Text.toString());
}否则{
返回文本(“工作内容”);
}
},
),
),
],
),
),
);
}
}