java - Dagger 注入(inject)的类在 Dagger 中保持为 null

Question

我正在尝试将 CacheManager 的实例注入(inject) GetTodoRepository 中，Dagger 可能会成功执行此操作，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Application类中设置Dagger(组件)

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) 从注入(inject)目标类中的Application类调用Component对象

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