Dagger v2：将2个不同的范围注入一个对象 [英] Dagger v2: Inject 2 different scopes into one object

问题描述

我将moduleA设置为应用程序范围的单例提供程序，将ModuleB设置为与用户相关的对象提供程序

I have moduleA setup as an application wide singleton provider, ModuleB as a user related object provider

我的用户显示片段将使用系统范围的总线向其他人发送消息并使用与用户相关的对象进行显示。

My user display fragment will use system wide bus to send message to others and use user related object to display.

问题无法将不同的scrope类注入一个对象。使用component.getX方法效果很好，但是首选注入方式。
错误消息：
@UserScope可能不引用具有不同作用域的绑定：@Provides @Singleton Bus ModuleA.provideBus（）

Problem cannot inject different scrope class into one object. Use component.getX method works fine, but inject is prefered way. Error message: @UserScope may not reference bindings with difference scopes: @Provides @Singleton Bus ModuleA.provideBus()

@Module
public class ModuleA {
  @Provides @Singleton Bus provideBus() {...}
}

作为用户相关信息提供者的模块B

Module B as user related Info provider

@Module
public class ModuleB{
  private final User user;
  public ModuleB(User user) {...}
  @Provides @UserScope User provideUser() {}
  @Provides @UserScope UserManager provideUserManager() {}
}

组件设置如下：

@Component (modules={ModuleA.class})
@Singleton
public interface ComponentA {
  Bus getBus();
  void inject(ClassA target);
}

@Component(modules={ModuleB.class})
@UserScope
public interface ComponentB {
  User getUser();
  UserManager getUserManager();
  void inject(ClassA target);
}


class UserFragment exrtends Fragment {
   @Inject Bus bus;
   @Inject UserManager userManager;
   public void onCreate() {
      getComponentA().inject(this);
      getComponentB().inject(this);
   }
}

推荐答案

尝试这种配置对我有用。确实缺少关于Dagger2的良好文档，因此我研究了一些开源代码示例，您可以在GitHub等中通过Dagger2之类的关键字找到这些代码。

Try this configuration, it works for me. There is really a lack of good documentation about Dagger2 so I studied a few open-source examples of code that you can find in GitHub etc by keyword like Dagger2.

应用程序级别组件

@Singleton
@Component(modules = AppModule.class)
public interface AppComponent {
    // exported for child-components
    Bus eventBus();
}

应用程序级别模块

@Module
public class AppModule {
    @Provides @Singleton
    Bus provideBus() {
        return BusProvider.getInstance();
    }
}

活动级别组件

@ActivityScope
@Component(dependencies=AppComponent.class, modules=MainActivityModule.class)
public interface MainActivityComponent {
    void inject( MainActivity mainActivity );
}

活动级别模块

@Module
public class MainActivityModule {
    private final MainActivity mActivity;

    public MainActivityModule( MainActivity activity ) {
        mActivity = activity;
    }

    @Provides
    MainActivityTitleController provideTitleController() {
        return new MainActivityTitleController( mActivity );
    }
}

Android应用程序类

Android Application class

public class MyApplication extends Application {
    private AppComponent mAppComponent;

    @Override
    public void onCreate() {
        super.onCreate();
        // Dagger2
        mAppComponent = Dagger_AppComponent.builder()
            .appModule( new AppModule( this ))
            .build();
    }

    public AppComponent getComponent() {
        return mAppComponent;
    }

    public static AppComponent getComponent( Context context ) {
        return ((MyApplication)context.getApplicationContext()).getComponent();
    }
}

最后是活动

public class MainActivity extends ActionBarActivity {

    // Injectable fields
    @Inject Bus mEventBus;
    @Inject MainActivityTitleController mTitleController;

    private MainActivityComponent mComponent;

    @Override
    protected void onCreate( Bundle savedInstanceState ) {
        // Dagger2
        mComponent = Dagger_MainActivityComponent.builder()
            .appComponent( ((MyApplication)getApplication()).getComponent() )
            .mainActivityModule( new MainActivityModule( this ) )
            .build();
        mComponent.inject( this );
    }
}

这篇关于Dagger v2：将2个不同的范围注入一个对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！