匕首2作用域環境問題

Question

我正在嘗試關注MVP/Dagger2/RxJava項目的this template。

我無法將活動上下文注入到演示者中，因爲我知道子組件對所有父提供的邏輯都有開放訪問權限，所以其他注入都會通過。

應用程序組件構建在Application類中，然後在基本演示者活動中進行訪問，然後注入演示者和其他人的相關依賴關係。配置持久組件主要用於保存演示者狀態。

如果我只是手動將上下文從活動傳遞給演示者，那麼DI的目的就是失敗。

我試圖添加範圍到所有組件和模塊，以確保依賴關係可以從圖中正確訪問，但是這不起作用。

我想使用上下文的構造函數注入，我實際上接收到演示者與之通信的活動中的上下文，但演示者沒有，引發錯誤。所以我想知道爲什麼這個活動可以訪問活動上下文，但是演示者卻沒有。

任何指導，將不勝感激。

錯誤

Error:(13, 8) error: [<packageName>.injection.component.ActivityComponent.inject(<packageName>.login.LoginActivity)] android.app.Activity cannot be provided without an @Inject constructor or from an @Provides-annotated method. 
android.app.Activity is injected at 
<packageName>.login.presenter.LoginActivityPresenter.<init>(activity, …) 
<packageName>.login.presenter.LoginActivityPresenter is injected at 
<packageName>.login.LoginActivity.presenter 
<packageName>.login.LoginActivity is injected at 
<packageName>.injection.component.ActivityComponent.inject(loginActivity) 
A binding with matching key exists in component: <packageName>.injection.component.ActivityComponent 

我的組件/模塊如下所示：

應用程序組件

@Singleton 
@Component(modules = {ApplicationModule.class, BusModule.class, PrefsModule.class, NetModule.class}) 
public interface ApplicationComponent { 
    @ApplicationContext Context context(); 
    Application application(); 
    EventBus bus(); 
    SharedPreferences prefs(); 
    Gson gson(); 
} 

應用模塊

@Module 
public class ApplicationModule { 
    protected final Application app; 

    public ApplicationModule(Application app) { 
     this.app = app; 
    } 

    @Provides 
    Application providesApplication() { 
     return app; 
    } 

    @Provides 
    @ApplicationContext 
    Context providesContext(){ 
     return app; 
    } 
} 

配置持久性組件

@ConfigPersistent 
@Component(dependencies = ApplicationComponent.class) 
public interface ConfigPersistentComponent { 

    ActivityComponent plus(ActivityModule activityModule); 

} 

活性成分

@PerActivity 
@Subcomponent(modules = ActivityModule.class) 
public interface ActivityComponent { 

    void inject(LoginActivity loginActivity); 

} 

活動模塊

@Module 
public class ActivityModule { 

    private Activity activity; 

    public ActivityModule(Activity activity) { 
    this.activity = activity; 
    } 

    @Provides 
    @PerActivity 
    Activity providesActivity() { 
    return activity; 
    } 

} 

應用類

public class App extends Application { 

    private ApplicationComponent applicationComponent; 

    @Override public void onCreate() { 
    super.onCreate(); 
    Timber.plant(new Timber.DebugTree()); 
    } 

    public static App get(Context context) { 
    return (App) context.getApplicationContext(); 
    } 

    public ApplicationComponent getComponent() { 
    if (applicationComponent == null) { 
     applicationComponent = DaggerApplicationComponent.builder() 
       .applicationModule(new ApplicationModule(this)) 
       .busModule(new BusModule()) 
       .netModule(new NetModule()) 
       .prefsModule(new PrefsModule()) 
       .build(); 
    } 
    return applicationComponent; 
    } 

} 

MainPresenter

@ConfigPersistent 
public class LoginActivityPresenter extends BasePresenter<LoginContract.View> { 

    Context context; 
    Gson gson; 

    @Inject 
    public LoginActivityPresenter(Activity activity, Gson gson) { 
    this.context = activity; 
    this.gson = gson; 
    } 

    @Override public void attachView(LoginContract.View view) { 
    super.attachView(view); 
    Timber.d("onAttach"); 
    } 

    @Override public void detachView() { 
    super.detachView(); 
    Timber.d("onDettach"); 
    disposableSubscriber.dispose(); 
    } 
} 

基地演示活動

public abstract class BasePresenterActivity extends AppCompatActivity { 

    private static final String KEY_ACTIVITY_ID = "KEY_ACTIVITY_ID"; 
    private static final AtomicLong NEXT_ID = new AtomicLong(0); 
    private static final Map<Long, ConfigPersistentComponent> sComponentsMap = new HashMap<>(); 

    private ActivityComponent activityComponent; 
    private long activityId; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     // Create the ActivityComponent and reuses cached ConfigPersistentComponent if this is 
     // being called after a configuration change. 
     activityId = savedInstanceState != null ? savedInstanceState.getLong(KEY_ACTIVITY_ID) : NEXT_ID.getAndIncrement(); 
     ConfigPersistentComponent configPersistentComponent; 
     if (!sComponentsMap.containsKey(activityId)) { 
      Timber.i("Creating new ConfigPersistentComponent id=%d", activityId); 
      configPersistentComponent = DaggerConfigPersistentComponent.builder() 
        .applicationComponent(App.get(this).getComponent()) 
        .build(); 
      sComponentsMap.put(activityId, configPersistentComponent); 
     } else { 
      Timber.i("Reusing ConfigPersistentComponent id=%d", activityId); 
      configPersistentComponent = sComponentsMap.get(activityId); 
     } 
     activityComponent = configPersistentComponent.plus(new ActivityModule(this)); 
    } 

主要活動

public class LoginActivity extends BasePresenterActivity implements LoginContract.View { 

    @Inject 
    EventBus bus; 
    @Inject 
    SharedPreferences prefs; 
    @Inject 
    Activity activity; 
    @Inject 
    LoginActivityPresenter presenter; 

    @Override 
    protected void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    activityComponent().inject(this); 
    setContentView(R.layout.activity_login); 
    presenter.attachView(this); 
    } 

    @Override protected void onDestroy() { 
    super.onDestroy(); 
    presenter.detachView(); 
    } 
} 

/********** ******** EDIT **/

爲了幫助保存演示者的狀態並仍然允許激活vity上下文被傳入，我的解決方案在下面發佈。歡迎任何反饋。

 @ActivityContext 
    public class LoginActivityPresenter extends BasePresenter<LoginContract.View> { 

     Context context; 

     @Inject 
     LoginStateHolder loginStateHolder; 

     @Inject 
     public LoginActivityPresenter(Context context, Gson gson) { 
     this.context = activity; 
     this.gson = gson; 
     } 
} 

@ConfigPersistent 
public class LoginStateHolder { 

    String title; 

    @Inject 
    public LoginStateHolder(Context context) { 
    title = "Save me"; 
    } 

    public void setTitle(String title) { 
    this.title = title; 
    } 

    public String getTitle() { 
    return title; 
    } 
} 

/*********** 編輯 - 21_5_17 *********/

例外：

Error:(13, 8) error: [<packagename>.injection.component.ActivityComponent.inject(<packagename>.login.ui.activity.LoginActivity)] android.app.Activity cannot be provided without an @Provides-annotated method. 
android.app.Activity is injected at 
<packagename>.login.presenter.LoginActivityPresenter.<init>(activity, …) 
<packagename>.login.presenter.LoginActivityPresenter is injected at 
<packagename>.login.ui.activity.LoginActivity.presenter 
<packagename>.login.ui.activity.LoginActivity is injected at 
<packagename>.injection.component.ActivityComponent.inject(loginActivity) 

登錄活動

public class LoginActivity extends BasePresenterActivity implements LoginContract.View { 

    @Inject 
    EventBus bus; 
    @Inject 
    SharedPreferences prefs; 
    @Inject 
    LoginActivityPresenter presenter; 

    @Override 
    protected void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    activityComponent().inject(this); 
    setContentView(R.layout.activity_login); 
    ButterKnife.bind(this); 
    presenter.attachView(this); 
    presenter.setupValidation(username, companyId, password); 

} 

登錄活動主持人

@ActivityContext 
public class LoginActivityPresenter extends BasePresenter<LoginContract.View> { 

    @Inject LoginPresenterStorage loginPresenterStorage; 

    Gson gson; 

    @Inject 
    public LoginActivityPresenter(Activity activity, Gson gson) { 
    this.context = activity; 
    this.gson = gson; 
    } 
} 

登錄演示存儲

@ConfigPersistent 
public class LoginPresenterStorage { 

    private String test = ""; 

    @Inject 
    public LoginPresenterStorage(Activity activity) { 
    test = "I didn't die"; 
    } 

    public String getTest() { 
    return test; 
    } 
} 

應用組件

@Singleton 
@Component(modules = {ApplicationModule.class, BusModule.class, PrefsModule.class, NetModule.class}) 
public interface ApplicationComponent { 

    @ApplicationContext Context context(); 
    Application application(); 
    EventBus bus(); 
    SharedPreferences prefs(); 
    Gson gson(); 

} 

活動構件

@ActivityContext 
@Subcomponent(modules = ActivityModule.class) 
public interface ActivityComponent { 

    void inject(LoginActivity loginActivity); 

} 

ConfigPersistentComponent

@ConfigPersistent 
@Component(dependencies = ApplicationComponent.class) 
public interface ConfigPersistentComponent { 

    ActivityComponent plus(ActivityModule activityModule); 

} 

活動模塊

@Module 
public class ActivityModule { 

    private Activity activity; 

    public ActivityModule(Activity activity) { 
    this.activity = activity; 
    } 

    @Provides 
    @ActivityContext 
    Activity providesActivity() { 
    return activity; 
    } 

} 

編輯

我提出使用的錯誤與活動模塊相同的活動上下文。因此，我沒有把活動注入主持人。更改活動模塊到原來的@peractivity範圍，請按照以下的答案將會使活動場景注射。

Answer 1

@ConfigPersistent 
public class LoginActivityPresenter extends BasePresenter<LoginContract.View> { 

通過與@ConfigPersistent範圍，你告訴匕首「在ConfigPersistentComponent管理這一類的實例」標記LoginActivityPresenter（即總是從一個給定的ConfigPersistentComponent實例返回相同的實例），這意味着它不應該訪問到像@ActivityScope這樣的狹義範圍內的任何東西。畢竟，ConfigPersistentComponent會活得比ActivityComponent，所以注射用活動的LoginPresenter沒有意義：你現在的樣子，你會得到相同的LoginPresenter實例與不同的活動。

「不能沒有@Inject構造被提供android.app.Activity」的消息來自代ConfigPersistentComponent的，它不具有活性結合。當然，你的ActivityComponent做，但這不是它正試圖存儲LoginPresenter其當前的註釋。

將該聲明切換到@ActivityScope，一切都會好：您將爲每個創建的Activity創建一個不同的LoginActivityPresenter，並且您還可以訪問@Singleton範圍（ApplicationComponent）和@ConfigPersistent範圍內的所有內容（ConfigPersistentComponent）。

@ActivityScope 
public class LoginActivityPresenter extends BasePresenter<LoginContract.View> {