abstract-factory 相关问题

"message": "方法 Illuminate\Auth\SessionGuard::factory 不存在。",

我正在尝试使用 "tymon/jwt-auth": "^1.0" 将 JWT 添加到 Laravel Framework 7.26.1。已按照文档设置一切。 https://jwt-auth.readthedocs.io/en/develop/quick-start/...

数组工厂 Laravel 上的随机选择值

我进行了用户迁移： $table->enum('type',['卖家','买家'])->default('卖家'); 我想在使用 ModelFactory 时如何获得随机值卖家或买家？ $factory->define(App\User::class,

Typescript 无法与 tsconfig.json 一起使用

在项目中使用 tsconfig 运行 tsc --watch 时，出现以下错误。 它需要 Node js 中的 React 和 Redux 类型。 错误 TS2688：找不到“abstract-leveldow...”的类型定义文件...

Laravel 中的策略对我不起作用，这是我的代码

我无法让策略在我的 Laravel 项目中工作，我安装了一个新项目来从头开始测试，我有这个控制器： 我无法让策略在我的 Laravel 项目中工作，我安装了一个新项目来从头开始测试，我有这个控制器： <?php namespace App\Http\Controllers; use App\Http\Controllers\Controller; use Illuminate\Http\Request; use App\Models\User; class UserController extends Controller { public function index() { $this->authorize('viewAny', auth()->user()); return response("Hello world"); } } 本政策： <?php namespace App\Policies; use Illuminate\Auth\Access\Response; use App\Models\User; class UserPolicy { public function viewAny(User $user): bool { return true; } } 这是我的模型 <?php namespace App\Models; // use Illuminate\Contracts\Auth\MustVerifyEmail; use Illuminate\Database\Eloquent\Factories\HasFactory; use Illuminate\Foundation\Auth\User as Authenticatable; use Illuminate\Notifications\Notifiable; use Laravel\Sanctum\HasApiTokens; class User extends Authenticatable { use HasApiTokens, HasFactory, Notifiable; /** * The attributes that are mass assignable. * * @var array<int, string> */ protected $fillable = [ 'name', 'email', 'password', ]; /** * The attributes that should be hidden for serialization. * * @var array<int, string> */ protected $hidden = [ 'password', 'remember_token', ]; /** * The attributes that should be cast. * * @var array<string, string> */ protected $casts = [ 'email_verified_at' => 'datetime', 'password' => 'hashed', ]; } 我收到错误 403：此操作未经授权。我希望有人能帮助我解决我的问题。谢谢你 我也尝试过修改AuthServiceProvider文件，但没有任何改变。 必须在 App\Providers\AuthServiceProvider 中添加您的策略吗？ protected $policies = [ User::class => UserPolicy::class ]; 您需要指定您正在使用的模型。具体来说，就是User。因此，传递当前登录的用户： $this->authorize('viewAny', auth()->user()); 此外，您正在尝试验证用户是否有权访问该页面。确保尝试访问该页面的人是用户，以便策略可以授权或不授权。 要在没有入门套件的情况下进行测试，请创建一个用户并使用它登录。 <?php namespace App\Http\Controllers; use Illuminate\Support\Facades\Auth; class UserController extends Controller { public function index() { $user = \App\Models\User::factory()->create(); Auth::login($user); $this->authorize('viewAny', auth()->user()); return response("Hello world"); } } 但是，如果您希望授予访客用户访问权限，您可以使用 ? 符号将 User 模型设为可选： public function viewAny(?User $user) { return true; }

.NET MAUI：自定义Shell TitleView并绑定到当前页面标题

我想用我自己的自定义布局替换默认的 Shell 标头，如下所示： 我想用我自己的自定义布局替换默认的 Shell 标头，如下所示： <?xml version="1.0" encoding="UTF-8" ?> <Shell x:Class="MyNamespace.App.AppShell" xmlns="http://schemas.microsoft.com/dotnet/2021/maui" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:local="clr-namespace:MyNamespace.App" xmlns:pages="clr-namespace:MyNamespace.App.Pages" BindingContext="{x:Static local:MainView.Instance}" Shell.FlyoutBehavior="{Binding ShellFlyoutType}" x:Name="shellMain"> <Shell.TitleView> <Grid ColumnDefinitions="*,200"> <Label BindingContext="{x:Reference shellMain}" Text="{Binding Path=CurrentPage.Title, Mode=OneWay}" FontSize="Large" TextColor="White" /> <ActivityIndicator IsRunning="{Binding IsBusy}" Color="Orange" Grid.Column="1" HorizontalOptions="End" /> </Grid> </Shell.TitleView> <ShellContent Title=" Login" ContentTemplate="{DataTemplate local:MainPage}" Route="login" FlyoutItemIsVisible="False" /> <ShellContent Title="Dashboard" ContentTemplate="{DataTemplate pages:DashboardPage}" Route="dashboard" /> </Shell> 我无法绑定当前页面标题。 我的 AppShell.xaml Shell 声明如下 <Shell ... x:Name="shellMain"> 作为替代方案，您可以在 OnNaviged 方法中设置 titleview ： 在 AppShell.xaml 中，定义标签的名称 <Shell.TitleView> <Grid ColumnDefinitions="*,200"> <Label BindingContext="{x:Reference shellMain}" x:Name="mylabel" FontSize="Large" TextColor="White" /> <ActivityIndicator IsRunning="{Binding IsBusy}" Color="Orange" Grid.Column="1" HorizontalOptions="End" /> </Grid> </Shell.TitleView> 在AppShell.xaml.cs中，重写OnNaviged方法，获取当前项目 protected override void OnNavigated(ShellNavigatedEventArgs args) { base.OnNavigated(args); var shellItem = Shell.Current?.CurrentItem; string title = shellItem?.Title; int iterationCount = 0; while (shellItem != null && title == null) { title = shellItem.Title; shellItem = shellItem.CurrentItem; if (iterationCount > 10) break; // max nesting reached iterationCount++; } myLabel.Text = title; } 希望它对你有用。 我正在尝试同样的方法来修改 TitleView 的外观。它可以在 iOS 上运行，尽管那里还有另一个错误。但在 Android 上我遇到了同样的问题。在前进导航中，它会更新标题，但当您按后退按钮时，标题不会更新。我已经打开了一个问题并添加了一个存储库。 https://github.com/dotnet/maui/issues/12416#issuecomment-1372627514 还有其他方法可以修改TitleView的外观吗？ 我使用视图模型开发了这个解决方法，主要不是为了提供 MVVM 解决方案，而是因为其他建议的答案对我不起作用。 （我怀疑 Liqun Shen 2 月 15 日针对他自己的问题的评论中的建议会起作用。但我没有注意到这一点，直到我自己修复）。 当前页面的标题保存在可由 shell 的视图模型和每个内容页面的视图模型访问的类中： public class ServiceHelper { private static ServiceHelper? _default; public static ServiceHelper Default => _default ??= new ServiceHelper(); internal string CurrentPageTitle { get; set; } = string.Empty; } shell 中每个内容页面的视图模型提供其页面标题。为了促进这一点，大部分工作都是由基本视图模型完成的，它们都是从该模型派生而来的： public abstract class ViewModelBase(string title) : ObservableObject { private ServiceHelper? _serviceHelper; public string Title { get; } = title; internal ServiceHelper ServiceHelper { get => _serviceHelper ??= ServiceHelper.Default; set => _serviceHelper = value; // For unit testing. } public virtual void OnAppearing() { ServiceHelper.CurrentPageTitle = Title; } } 每个 shell 内容页面视图模型只需要让其基础视图模型知道它的标题： public class LocationsViewModel : ViewModelBase { public LocationsViewModel() : base("Locations") { } } 每个 shell 内容页面都需要在其视图模型中触发所需的事件响应方法： public partial class LocationsPage : ContentPage { private LocationsViewModel? _viewModel; public LocationsPage() { InitializeComponent(); } private LocationsViewModel ViewModel => _viewModel ??= (LocationsViewModel)BindingContext; protected override void OnAppearing() { base.OnAppearing(); ViewModel.OnAppearing(); } } Shell 的视图模型为标题栏提供当前页面的标题： public class AppShellViewModel() : ViewModelBase(Global.ApplicationTitle) { private string _currentPageTitle = string.Empty; public string CurrentPageTitle { get => _currentPageTitle; set { _currentPageTitle = value; OnPropertyChanged(); } } public void OnNavigated() { CurrentPageTitle = ServiceHelper.CurrentPageTitle; } } Shell 需要在其视图模型中触发所需的事件响应方法： public partial class AppShell : Shell { private AppShellViewModel? _viewModel; public AppShell() { InitializeComponent(); } private AppShellViewModel ViewModel => _viewModel ??= (AppShellViewModel)BindingContext; protected override void OnNavigated(ShellNavigatedEventArgs args) { base.OnNavigated(args); ViewModel.OnNavigated(); } } 最后，Shell 的 XAML 在标题栏/导航栏上显示由 Shell 视图模型提供的当前页面的标题： <Shell.TitleView> <HorizontalStackLayout VerticalOptions="Fill"> <Image Source="falcon_svg_repo_com.png" HeightRequest="50"/> <Label x:Name="CurrentPageTitleLabel" Text="{Binding CurrentPageTitle}" FontSize="24" Margin="10,0" VerticalTextAlignment="Center"/> </HorizontalStackLayout> </Shell.TitleView>

错误：在此 BlocBuilder<InternetBloc> Widget<InternetBloc, InternetState> 上方找不到正确的提供程序

我在尝试将 flutter_bloc 集成到 flutter 项目中时遇到错误。 错误：在此 BlocBuilder 上方找不到正确的 Provider 我在尝试将 flutter_bloc 集成到 flutter 项目中时遇到错误。 错误：在此 BlocBuilder Widget 上方找不到正确的提供者 这是我正在使用的代码示例。 internet_state.dart abstract class InternetState{} class InitialInternetState extends InternetState{} class LostConnectionInternetState extends InternetState{} class GainConnectionInternetState extends InternetState{} internet_event.dart abstract class InternetEvent{} class LostConnectionEvent extends InternetEvent{} class GainConnectionEvent extends InternetEvent{} internet_bloc.dart class InternetBloc extends Bloc<InternetEvent, InternetState>{ final Connectivity _connectivity = Connectivity(); StreamSubscription? streamSubscription; InternetBloc() : super(InitialInternetState()){ on<GainConnectionEvent>((event, emit) => emit(GainConnectionInternetState())); on<LostConnectionEvent>((event, emit) => emit(LostConnectionInternetState())); _connectivity.onConnectivityChanged.listen((event) { if(event == ConnectivityResult.mobile || event == ConnectivityResult.wifi){ add(GainConnectionEvent()); } else { add(LostConnectionEvent()); } }); } @override Future<void> close() { streamSubscription?.cancel(); return super.close(); } } main.dart class MyApp extends StatelessWidget { const MyApp({super.key}); @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple), useMaterial3: true, ), home: const MyHomePage(title: 'Flutter Demo Home Page'), ); } } class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: Text(title),), body: SafeArea( child: Center(child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, )), ),); } } 我明白了。 ======== 小部件库捕获异常====================================== =================== 构建 MediaQuery(MediaQueryData(size: Size(392.7, 783.3), devicePixelRatio: 2.8, textScaler: noscaling, platformBrightness: Brightness.light, padding: EdgeInsets.zero, viewPadding: EdgeInsets.zero, viewInsets: EdgeInsets 时抛出以下 ProviderNotFoundException。零，systemGestureInsets：EdgeInsets（29.8，24.0，29.8，8.0），alwaysUse24HourFormat：假，accessibleNavigation：假，highContrast：假，onOffSwitchLabels：假，disableAnimations：假，invertColors：假，boldText：假，navigationMode：传统，gestureSettings：DeviceGestureSettings （touchSlop：8.0），显示功能：[]））： 错误：无法在此 BlocBuilder Widget 之上找到正确的提供程序 发生这种情况是因为您使用了不包含提供程序的 BuildContext 你的选择。有以下几种常见场景： 您在main.dart中添加了一个新的提供程序并执行了热重载。 要修复此问题，请执行热重启。 您尝试阅读的提供商处于不同的路线。 提供商具有“范围”。因此，如果您在路线中插入提供者，那么 其他路线将无法访问该提供商。 您使用了 BuildContext，它是您尝试读取的提供程序的祖先。 确保 BlocBuilder 位于您的 MultiProvider/Provider 下。 当您创建提供程序并尝试立即读取它时，通常会发生这种情况。 例如，代替： Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // Will throw a ProviderNotFoundError, because `context` is associated // to the widget that is the parent of `Provider<Example>` child: Text(context.watch<Example>().toString()), ); } 考虑使用builder，如下所示： Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // we use `builder` to obtain a new `BuildContext` that has access to the provider builder: (context, child) { // No longer throws return Text(context.watch<Example>().toString()); } ); } 如果这些解决方案都不起作用，请考虑在 StackOverflow 上寻求帮助： https://stackoverflow.com/questions/tagged/flutter The relevant error-causing widget was: SafeArea SafeArea:file:///Users/../Projects/flutterTest/bloc_test/lib/main.dart:37:13 When the exception was thrown, this was the stack: #0 Provider._inheritedElementOf (package:provider/src/provider.dart:343:7) #1 Provider.of (package:provider/src/provider.dart:293:30) #2 ReadContext.read (package:provider/src/provider.dart:649:21) #3 _BlocBuilderBaseState.initState (package:flutter_bloc/src/bloc_builder.dart:130:36) #4 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:5602:55) #5 ComponentElement.mount (package:flutter/src/widgets/framework.dart:5447:5) ... Normal element mounting (4 frames) #9 Element.inflateWidget (package:flutter/src/widgets/framework.dart:4326:16) #10 Element.updateChild (package:flutter/src/widgets/framework.dart:3831:20) #11 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #12 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #13 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #14 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #15 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #16 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #17 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #18 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #19 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #20 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #21 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #22 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #23 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #24 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #25 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #26 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #27 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #28 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #29 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #30 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #31 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #32 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #33 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #34 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #35 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #36 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #37 Element.updateChildren (package:flutter/src/widgets/framework.dart:3964:32) #38 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6896:17) #39 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #40 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #41 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #42 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #43 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #44 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #45 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #46 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #47 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #48 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #49 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #50 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #51 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #52 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #53 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #54 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #55 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #56 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #57 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #58 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #59 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #60 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #61 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #62 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #63 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #64 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #65 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #66 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #67 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #68 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #69 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #70 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #71 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #72 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #73 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #74 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #75 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #76 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #77 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #78 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #79 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #80 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #81 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #82 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #83 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #84 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #85 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #86 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #87 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #88 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #89 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #90 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #91 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #92 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #93 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #94 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #95 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #96 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #97 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #98 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #99 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #100 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #101 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #102 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #103 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #104 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #105 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #106 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #107 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #108 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #109 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2895:19) #110 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:984:21) #111 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:457:5) #112 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1325:15) #113 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1255:9) #114 SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:978:7) #118 _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12) (elided 3 frames from class _Timer and dart:async-patch) ==================================================================================================== 我不想使用像 MultiProvider 这样的全局提供程序。 您应该在某处创建 InternetBloc 并提供它。 MultiProvider 本身并不是全局的，它只是多个。 更多信息在这里：https://bloclibrary.dev/#/flutterbloccoreconcepts?id=blocprovider 所以，如果您不想使用全局提供程序，它将看起来像这样： class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(title), ), body: SafeArea( child: Center( child: BlocProvider<InternetBloc>( create: ( context) => InternetBloc(), child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, ), ), ), ), ); } } 要使用 BlocBuilder，您需要在 Widget 树中放置一个 BlocProvider。最佳实践是将其放置得尽可能深。在您的情况下，只需将 BlocProvider 放在 BlocBuilder 之上。 此外 MultiProvider / MultiBlocProvider 不是全局 Provider。它只是一个提供多个 Provider/BlocProvider 的便捷小部件。 class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(title), ), body: SafeArea( child: Center( // Now everything below that can access the InternetBloc child: BlocProvider<InternetBloc>( create: (_) => InternetBloc(), child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, ), ), ), ), ); } }