Flutter 颤振找不到正确的提供程序<;集团>;导航到不同路线后
我正在使用bloc来处理注册表单的状态。但我得到了一个错误:Flutter 颤振找不到正确的提供程序<;集团>;导航到不同路线后,flutter,dart,flutter-provider,flutter-bloc,Flutter,Dart,Flutter Provider,Flutter Bloc,我正在使用bloc来处理注册表单的状态。但我得到了一个错误: 错误:在此BlocBuilder小部件上方找不到正确的提供程序 正如您在错误中看到的,我确实使用了blocCreateDidBloc和stateCreateDidState并通过BlocBuilder获取它们。 BlocBuilder位于我的“注册”页面中,在我的例子中,该页面称为创建。当我从介绍页面导航到创建页面时,会发生此错误。 下面是我的MaterialApp摘录,其中我使用RepositoryProvider和BlocProv
错误:在此BlocBuilder小部件上方找不到正确的提供程序
正如您在错误中看到的,我确实使用了blocCreateDidBloc
和stateCreateDidState
并通过BlocBuilder获取它们。
BlocBuilder位于我的“注册”页面中,在我的例子中,该页面称为创建
。当我从介绍页面导航到创建页面时,会发生此错误。
下面是我的MaterialApp
摘录,其中我使用RepositoryProvider
和BlocProvider
包装创建页面,以便创建页面可以访问Bloc和存储库。但是由于某种原因,创建
页面在导航到创建页面后没有找到CreateDidBloc
的BlocProvider
initialRoute: "/introduction",
routes: {
"/introduction": (context) => Introduction(),
"/create": (context) => RepositoryProvider(
create: (context) => CreateDidRepository(),
child: BlocProvider(
create: (BuildContext context) => CreateDidBloc(
repo: context.read<CreateDidRepository>(),
),
child: Creation(),
),
),
},
创建(注册)页面:
我找到了BlocBuilder在导航后找不到CreateDidBloc
的原因。发生该错误的原因是,在颤振中导航会将页面推到小部件树中MaterialApp的正下方。这意味着我新导航的页面位于BlocProvider之上,BlocProvider在MaterialApp下面的小部件树中指定。
为了解决这个问题,我只是用MultiBlocProvider和RepositoryProvider包装了我的MaterialApp,这样无论我采用何种路线,Bloc都可以在全球范围内提供。
这是我可以全局定义集团的重要摘录:
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return RepositoryProvider(
create: (context) => CreateDidRepository(),
child: MultiBlocProvider(
providers: [
BlocProvider<LanguageBloc>(
create: (context) =>
LanguageBloc(LanguagePreference.getLanguage())),
BlocProvider<CreateDidBloc>(
create: (context) =>
CreateDidBloc(repo: context.read<CreateDidRepository>()))
],
child: BlocBuilder<LanguageBloc, LanguageState>(
builder: (context, state) {
return MaterialApp(...)
类MyApp扩展了无状态小部件{
@凌驾
小部件构建(构建上下文){
返回存储提供程序(
create:(context)=>CreateDidRepository(),
子对象:MultiBlocProvider(
供应商:[
BlocProvider(
创建:(上下文)=>
LanguageBloc(LanguagePreference.getLanguage()),
BlocProvider(
创建:(上下文)=>
CreateDidBloc(repo:context.read())
],
孩子:BlocBuilder(
生成器:(上下文、状态){
返回材料PP(…)
@override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
body: Column(
children: [
Expanded(
child: PageView(
physics: const NeverScrollableScrollPhysics(),
controller: _pageController,
onPageChanged: (index) {
setState(() => currentStep = index);
},
children: [
Step1(),
Step2(),
Step3(),
],
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
BlocBuilder<CreateDidBloc, CreateDidState>(
builder: (context, state) {
return ElevatedButton(
onPressed: () {
next();
},
child: Text(L.of(context).next));
},
),
BlocBuilder<CreateDidBloc, CreateDidState>(
builder: (context, state) {
return OutlinedButton(
onPressed:
state.formStatus is FormSubmitting ? null : cancel,
child: Text(L.of(context).back));
},
)
],
),
const SizedBox(
height: 16,
)
],
)));
}
When the exception was thrown, this was the stack
#0 Provider._inheritedElementOf
#1 Provider.of
#2 ReadContext.read
#3 _BlocBuilderBaseState.initState
#4 StatefulElement._firstBuild
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return RepositoryProvider(
create: (context) => CreateDidRepository(),
child: MultiBlocProvider(
providers: [
BlocProvider<LanguageBloc>(
create: (context) =>
LanguageBloc(LanguagePreference.getLanguage())),
BlocProvider<CreateDidBloc>(
create: (context) =>
CreateDidBloc(repo: context.read<CreateDidRepository>()))
],
child: BlocBuilder<LanguageBloc, LanguageState>(
builder: (context, state) {
return MaterialApp(...)