Android 颤振:在同一树中使用Multiprovider和Consumer的依赖注入
我试图将在同一树级别创建的服务实例注入到另一个提供者中。但是在访问提供者时,我得到了ProviderNotFoundException。 在以下代码中,NotificationService依赖于AuthService。它需要在构造函数中传递。因此,我使用文档中提到的Consumer和Provider.value注入它: 以下是伪代码:Android 颤振:在同一树中使用Multiprovider和Consumer的依赖注入,android,flutter,dependency-injection,flutter-provider,Android,Flutter,Dependency Injection,Flutter Provider,我试图将在同一树级别创建的服务实例注入到另一个提供者中。但是在访问提供者时,我得到了ProviderNotFoundException。 在以下代码中,NotificationService依赖于AuthService。它需要在构造函数中传递。因此,我使用文档中提到的Consumer和Provider.value注入它: 以下是伪代码: return MultiProvider( providers: [ Provider<AuthService>(
return MultiProvider(
providers: [
Provider<AuthService>(
create: (ctx) => AuthService(_storage),
dispose: (ctx, v) => v.dispose(),
),
Consumer<AuthService>(
builder: (context, v, child) {
return Provider.value(
value: Provider<NotificationService>(
create: (ctx) => NotificationService(v),
dispose: (ctx, v) => v.dispose(),
),
child: child
);
},
)
],
child: MyApp()
);
错误:
I/flutter ( 4614): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 4614): The following ProviderNotFoundException was thrown building MyApp(dirty, dependencies:
I/flutter ( 4614): [_DefaultInheritedProviderScope<AuthService>]):
I/flutter ( 4614): Error: Could not find the correct Provider<NotificationService> above this MyApp Widget
I/flutter ( 4614):
I/flutter ( 4614): To fix, please:
I/flutter ( 4614):
I/flutter ( 4614): * Ensure the Provider<NotificationService> is an ancestor to this MyApp Widget
I/flutter ( 4614): * Provide types to Provider<NotificationService>
I/flutter ( 4614): * Provide types to Consumer<NotificationService>
I/flutter ( 4614): * Provide types to Provider.of<NotificationService>()
I/flutter ( 4614): * Ensure the correct `context` is being used.
I/flutter ( 4614):
我不完全理解这一点,我很确定上面的代码中有错误。我做错了什么 您使用Provider.value的方式无效。但实际上你并不需要消费者+提供者。你可以做:
多供应商
供应商:[
Providercreate:=>A,
Providercreate:context=>BProvider.ofcontext,listen:false,
],
您使用Provider.value的方式无效。但实际上你并不需要消费者+提供者。你可以做:
多供应商
供应商:[
Providercreate:=>A,
Providercreate:context=>BProvider.ofcontext,listen:false,
],
非常感谢。这就解决了问题。我浏览了api文档:。但我无法真正理解这个解释,listen:false到底做了什么?@dora查看我的文章,以便更好地理解listen标志。它还引用了文档。@Rémi如果要在提供程序A更新时更新提供程序B,那么我们需要为B使用代理提供程序。如果我错了,请更正。谢谢。这就解决了问题。我浏览了api文档:。但我无法真正理解这个解释,listen:false到底做了什么?@dora查看我的文章,以便更好地理解listen标志。它还引用了文档。@Rémi如果要在提供程序A更新时更新提供程序B,那么我们需要为B使用代理提供程序。如果我错了,请纠正我。
I/flutter ( 4614): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 4614): The following ProviderNotFoundException was thrown building MyApp(dirty, dependencies:
I/flutter ( 4614): [_DefaultInheritedProviderScope<AuthService>]):
I/flutter ( 4614): Error: Could not find the correct Provider<NotificationService> above this MyApp Widget
I/flutter ( 4614):
I/flutter ( 4614): To fix, please:
I/flutter ( 4614):
I/flutter ( 4614): * Ensure the Provider<NotificationService> is an ancestor to this MyApp Widget
I/flutter ( 4614): * Provide types to Provider<NotificationService>
I/flutter ( 4614): * Provide types to Consumer<NotificationService>
I/flutter ( 4614): * Provide types to Provider.of<NotificationService>()
I/flutter ( 4614): * Ensure the correct `context` is being used.
I/flutter ( 4614):