匕首2週期注射

Question

我有兩個singletone類，我想將它們注入到Fragments，Activites等中，但我也要將它們注入彼此。 在這一點上，我總是得到SO錯誤。

public class AdverticumChecker implements IAdverticumChecker { 

    @Inject BannerManager bannerManager; 

    public AdverticumChecker(Context context) { 
     IndexApplication.getApplication().getAppComponent().inject(this); 
    } 
} 

public class BannerManager { 
    @Inject IAdverticumChecker adverticumChecker; 

    public BannerManager(){ 
     IndexApplication.getApplication().getAppComponent().inject(this); 
    } 
} 

這些模塊

@Module 
public class BannerManagerModule { 

     @Singleton 
     @Provides 
     BannerManager provideBannerManager(){ 
      return new BannerManager(); 
     } 
    } 

@Module 
public class AdverticumCheckerModule { 
    private Context context; 

    public AdverticumCheckerModule(Context context){ 
     this.context = context; 
    } 

    @Singleton 
    @Provides 
    IAdverticumChecker provideAdverticumChecker(){ 
     return new AdverticumChecker(context); 
    } 
} 

我在應用程序類建立圖一次。 這裏是錯誤：第一

FATAL EXCEPTION: main java.lang.StackOverflowError at com.aff.index.adverticum.AdverticumChecker_MembersInjector.injectMembers(AdverticumChecker_MembersInjector.java:38) at com.aff.index.adverticum.AdverticumChecker_MembersInjector.injectMembers(AdverticumChecker_MembersInjector.java:8) at com.aff.index.dagger.DaggerAppComponent.inject(DaggerAppComponent.java:679) at com.aff.index.adverticum.AdverticumChecker.(AdverticumChecker.java:50) at com.aff.index.dagger.AdverticumCheckerModule.provideAdverticumChecker(AdverticumCheckerModule.java:30) at com.aff.index.dagger.AdverticumCheckerModule_ProvideAdverticumCheckerFactory.get(AdverticumCheckerModule_ProvideAdverticumCheckerFactory.java:24) at com.aff.index.dagger.AdverticumCheckerModule_ProvideAdverticumCheckerFactory.get(AdverticumCheckerModule_ProvideAdverticumCheckerFactory.java:8) at dagger.internal.DoubleCheck.get(DoubleCheck.java:46) at com.aff.index.adverticum.BannerManager_MembersInjector.injectMembers(BannerManager_MembersInjector.java:67) at com.aff.index.adverticum.BannerManager_MembersInjector.injectMembers(BannerManager_MembersInjector.java:11) at com.aff.index.dagger.DaggerAppComponent.inject(DaggerAppComponent.java:704) at com.aff.index.adverticum.BannerManager.(BannerManager.java:89) at com.aff.index.dagger.BannerManagerModule.provideBannerManager(BannerManagerModule.java:21) at com.aff.index.dagger.BannerManagerModule_ProvideBannerManagerFactory.get(BannerManagerModule_ProvideBannerManagerFactory.java:24) at com.aff.index.dagger.BannerManagerModule_ProvideBannerManagerFactory.get(BannerManagerModule_ProvideBannerManagerFactory.java:8) at dagger.internal.DoubleCheck.get(DoubleCheck.java:46) at com.aff.index.adverticum.AdverticumChecker_MembersInjector.injectMembers(AdverticumChecker_MembersInjector.java:39) at com.aff.index.adverticum.AdverticumChecker_MembersInjector.injectMembers(AdverticumChecker_MembersInjector.java:8) at com.aff.index.dagger.DaggerAppComponent.inject(DaggerAppComponent.java:679)

Answer 1

第一件事，這...

@Singleton 
@Provides 
IAdverticumChecker provideAdverticumChecker(){ 
    return new AdverticumChecker(context); 
} 
... 
public AdverticumChecker(Context context) { 
    IndexApplication.getApplication().getAppComponent().inject(this); 
} 

規避什麼DI代表，基本上依賴注入，而不是在構造函數中注入他們讓一些靜態訪問神奇 - 這種方式AdvertiumChecker幾乎不可能測試！列出你所有的依賴構造函數的參數，而不是做這樣的：

@Singleton 
@Provides 
IAdverticumChecker provideAdverticumChecker(BannerManager bannerManager){ 
    return new AdverticumChecker(bannerManager); 
} 
... 
private BannerManager mBannerManager; 
public AdverticumChecker(BannerManager bannerManager) { 
    mBannerManager = bannerManager; 
} 

匕首會自動填補國內空白，爲你在這裏，構建一個適當的圖表。其次，如果BannerManager的構建依賴於IAdvertiumChecker的實例，那麼您顯然會有一個循環依賴關係，Dagger會錯誤地回答這個問題。通常情況下，這聽起來像不好的設計，但有時它不能以不同的方式執行，以防在運行時需要某些東西。

在這種情況下，與Lazy注射，即無論是

@Inject 
Lazy<BannerManager> mLazyBannerManager; 
... 
mLazyBannerManager.get().doSomething(); 

或

IAdvertiumChecker providerAdvertiumChecker(Lazy<BannerManager> lazyBannerManager) { 
    return new AdverticumChecker(lazyBannerManager); 
} 

希望這有助於工作。