匕首 2 问题:如果没有@Provides方法，则无法提供

Question

我在我的项目中玩dagger 2，然后我卡在了这个错误编译上。-> Error:(18, 21) error: ....MyManager cannot be provided without an @Provides-annotated method. ...MyManager is injected at ...SignInPresenter.<init>(myManager) ...SignInPresenter is provided at ...SignInComponent.signInPresenter()

我试图研究这个主题，但我无法准确地指出我的代码中的错误。我想我在某处犯了一个小错误，或者我理解了 Dagger2 中的错误。如果有人能指出错误。我将不胜感激。

我的经理

public interface MyManager {
    Observable<User> getAllUsers();
}

登录演示者

 @Inject
    public SignInPresenter(MyManager myManager) {
        this.myManager= myManager;
    }

我在MySignInFragment中做了这样的事情

   @Override protected void injectDependencies() {
        signInComponent = DaggerSignInComponent.builder()
                .myApplicationComponent(MyDaggerApplication.getMyComponents())
               .build();
    }

登录组件

@Component(modules = {MyModule.class},
        dependencies = {MyApplicationComponent.class})
public interface SignInComponent {
    SignInPresenter signInPresenter();
}

这是我的应用程序

public class MyDaggerApplication extends Application {
    private static MyApplicationComponent myApplicationComponent;

    @Override
    public void onCreate() {
        super.onCreate();
        myApplicationComponent = DaggerMyApplicationComponent.create();
        myApplicationComponent = DaggerMyApplicationComponent.builder().myModule(new MyModule(this)).build();
        myApplicationComponent.inject(this);
    }
    public MyApplicationComponent getMyAppComponents(){
        return myApplicationComponent;
    }
    public static MyApplicationComponent getMyComponents(){
        return myApplicationComponent;
    }
}

我的模块和组件类

@Component(modules = {MyModule.class})
public interface MyApplicationComponent {
    void inject(MyDaggerApplication myDaggerApplication);
}
@Module
public class MyModule {
    private final MyDaggerApplication myDaggerApplication;
    public MyModule(MyDaggerApplication myDaggerApplication){
        this.myDaggerApplication = myDaggerApplication;
    }
    @Provides
    @Singleton
    Context providesApplicationContext() {
        return this.myDaggerApplication;
    }
    @Provides
    @Singleton
    SharedPreferences providesSharedPreferences(Context context) {
        return context.getSharedPreferences("My_Pref", Context.MODE_PRIVATE);
    }
    @Provides
    @Singleton
    public MyDefaultManager providesMyDefaultManager(MyDefaultManager myDefaultManager,Context context){
        return myDefaultManager.getInstance(context);
    }
}

我猜我在DaggerApplication做错了什么.任何建议将不胜感激。:)

Answer 1

假设 MyDefaultManager 实现了 MyManager ，将 MyModule 中的最终提供程序更改为：

@Provides
@Singleton
public MyManager providesMyDefaultManager(MyDefaultManager myDefaultManager,Context context){
    return myDefaultManager.getInstance(context);
}

因为您要返回? implements MyManager的实例，而不是专门返回MyDefaulManager。