Dagger 2活动上下文/应用上下文模块

Question

@Singleton
@dagger.Component(modules = {
    AppModule.class
})
public interface AppComponent {
        void inject(MyApp application);
        Model model();
        Context context();<--- should provide the application Context for the Object above (model)
...

实现如下所示

@dagger.Module
public class AppModule {

    private final Application app;
    public ApplModule(Application app) {
        this.app = app;
    }

    @Provides
    @Singleton
    Model provideModel(Bus bus) {
        return new Model(bus);
    }

    @Provides
    @Singleton
    Context provideApplicationContext() {
        return app.getApplicationContext();
    }
...

>

其次，我有一个活动范围组件网，我提供了当前活动和需要上下文的不同视图。

  @ActivityScope
    @Component(
            dependencies = AppComponent.class
            , modules = {ActivityModule.class}
    )
    public interface ActivityComponent {
        void inject(MyActivity activity);
        Context context(); <---should provide the activity's context
        MyView homeView(); <----takes a Context as a contructor parameter

@module public class ActivityModule{private

public ActivityModule(Activity activity) {

    this.activity = activity;
}

@Provides
@ActivityScope
public Activity activity() {
    return activity;
}


@Provides
@ActivityScope
@Named("viewcontext") <----- if I removed this I get an error from Dagger
public Context context() {
    return activity;
}

@Provides
@ActivityScope
MyView provideZeView(Bus bus, Model model) { <---- previously receiving the ApplicationContext as a parameter 
    MyView v = new MyView(activity, bus, model); <---- must pass the activity otherwise passing the Context reveived is the ApplicationContext
    return v;
}

Answer 1

可以使用这样的限定符。在两个独立的文件中定义以下内容：

@Qualifier
@Retention(RetentionPolicy.RUNTIME)
public @interface ActivityContext {
}

@Qualifier
@Retention(RetentionPolicy.RUNTIME)
public @interface ApplicationContext {
}

然后在您的ActivityModule中执行以下操作：

@Provides
@ActivityScope
@ActivityContext
public Context context() {
    return activity;
}

同样地，在appmodule中执行以下操作：

 @Provides
    @Singleton
@ApplicationContext
    Context provideApplicationContext() {
        return app.getApplicationContext();
    }

例如，在您的活动中，您可以这样做：

  @Inject @ApplicationContext
    Context c;

它将注入应用程序上下文。

在一个模块中，您可以这样做，例如：

  @Provides
    @ActivityScope
    LoginPresenter provideLoginPresenter(@ActivityContext Context context) {
        return new LoginPresenter(context);
    }