您可以复制粘贴运行下面的完整代码 1 和 2
您可以提供UniqueKey()
to Scaffold
or TextFormField
强制重新创建
您可以参考https://medium.com/flutter/keys-what-are-they-good-for-13cb51742e7d详细信息
如果 Element 的 key 与相应 Widget 的 key 不匹配。这会导致 Flutter 停用这些元素并删除对元素树中元素的引用
解决方案一:
return Scaffold(
key: UniqueKey(),
body: Form(
解决方案2:
TextFormField(
key: UniqueKey(),
工作演示
完整代码1Scaffold
with UniqueKey
import 'package:flutter/material.dart';
import 'package:bloc/bloc.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'dart:developer' as developer;
void main() {
runApp(MyApp());
}
enum Event { first }
class ExampleBloc extends Bloc<Event, int> {
ExampleBloc() : super(0);
@override
Stream<int> mapEventToState(Event event) async* {
yield state + 1;
}
}
class MyApp extends StatelessWidget {
const MyApp({Key key}) : super(key: key);
@override
Widget build(BuildContext context) {
print("build");
return MaterialApp(
home: BlocProvider(
create: (_) => ExampleBloc(),
child: Builder(
builder: (contex) => SafeArea(
child: BlocConsumer<ExampleBloc, int>(
listener: (context, state) {},
builder: (context, int state) {
print("state ${state.toString()}");
developer.log(state.toString());
return Scaffold(
key: UniqueKey(),
body: Form(
child: Column(
children: [
TextFormField(
autocorrect: false,
initialValue: state.toString(),
),
RaisedButton(
child: Text('Press'),
onPressed: () {
context.bloc<ExampleBloc>().add(Event.first);
},
)
],
),
),
);
}),
),
),
),
);
}
}
完整代码2TextFormField
with UniqueKey
import 'package:flutter/material.dart';
import 'package:bloc/bloc.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'dart:developer' as developer;
void main() {
runApp(MyApp());
}
enum Event { first }
class ExampleBloc extends Bloc<Event, int> {
ExampleBloc() : super(0);
@override
Stream<int> mapEventToState(Event event) async* {
yield state + 1;
}
}
class MyApp extends StatelessWidget {
const MyApp({Key key}) : super(key: key);
@override
Widget build(BuildContext context) {
print("build");
return MaterialApp(
home: BlocProvider(
create: (_) => ExampleBloc(),
child: Builder(
builder: (contex) => SafeArea(
child: BlocConsumer<ExampleBloc, int>(
listener: (context, state) {},
builder: (context, int state) {
print("state ${state.toString()}");
developer.log(state.toString());
return Scaffold(
body: Form(
child: Column(
children: [
TextFormField(
key: UniqueKey(),
autocorrect: false,
initialValue: state.toString(),
),
RaisedButton(
child: Text('Press'),
onPressed: () {
context.bloc<ExampleBloc>().add(Event.first);
},
)
],
),
),
);
}),
),
),
),
);
}
}