Dagger 注入 class 在 Dagger 中一直为空

Question

我正在尝试将 CacheManager 的一个实例注入 GetTodoRepository 中，Dagger 可能会成功，因为我没有收到任何与 Dagger 相关的错误。但是当在 GetTodoRepository 中使用 cacheManager 时，我得到一个 NullPointerException

public class GetTodoRepository {

    @Inject
    public CacheManager cacheManager;

    public RetrofitService retrofitService;
    private ResultListener listener;

    public GetTodoRepository(@NonNull ResultListener listener) {
        this.retrofitService = new RetrofitService();
        this.listener = listener;
    }
}

@Module
public class AppModule {

    private Application application;

    public AppModule(Application application) {
        this.application = application;
    }

    @Provides
    @Singleton
    public Context providesApplicationContext() {
        return application.getApplicationContext();
    }

    @Provides
    @Singleton
    public CacheManager provideCacheManager(Context Context) {
        return new CacheManager(Context);
    }

}



@Singleton
@Component(modules = AppModule.class)
public interface TodoComponents {
    void inject(MainViewModel mainViewModel);
    void inject(CacheManager cacheManager);
    void inject(GetTodoRepository getTodoRepository);
    void inject(PostTodoRepository postTodoRepository);
}

Answer 1

1) 在应用程序中设置 Dagger（组件）class

public class TodoApplication extends Application {

private static AppComponent components;

@Override
public void onCreate() {
    super.onCreate();
    components = DaggerAppComponent.builder()
            .appModule(new AppModule(this))
            .build();
}


public static AppComponent getAppComponent() {
    return components;
}

}

2) 在注入目标class

中调用来自Applicationclass的Component对象

public GetTodoRepository(@NonNull ResultListener listener) {
    this.listener = listener;
    TodoApplication.getAppComponent().inject(this);
}

Dagger 注入 class 在 Dagger 中一直为空

Dagger injected class keeps being null with Dagger

java

android

dagger

dagger-2