组件中存在具有匹配键的绑定：dagger 2.12

Question

我正在使用 Dagger 2.12。 我的应用程序中有三个活动：Splash、Login、Main； Splash Activity 的代码很少，所以我没有将它添加到匕首图中！ 我有两个片段“登录片段”和“地址管理器片段”，它们希望在我的活动（登录和主）中有这些片段。 由于某些原因，我不想使用@ContributesAndroidInjector 并得到这个错误：

public interface AppComponent {
       ^
   ir.sabaap.jahadattendancesystem.di.component.LoginFragmentComponent.Builder is injected at
   ir.sabaap.jahadattendancesystem.di.module.FragmentBuilder.bindLoginFragment(builder)
   java.util.Map<java.lang.Class<? extends androidx.fragment.app.Fragment>,javax.inject.Provider<dagger.android.AndroidInjector.Factory<? extends androidx.fragment.app.Fragment>>> is injected at
   dagger.android.DispatchingAndroidInjector.<init>(injectorFactories)
   dagger.android.DispatchingAndroidInjector<androidx.fragment.app.Fragment> is injected at
   ir.sabaap.jahadattendancesystem.ui.main.MainActivity.fragmentDispatchingAndroidInjector
   ir.sabaap.jahadattendancesystem.ui.main.MainActivity is injected at
   dagger.android.AndroidInjector.inject(arg0)
   A binding with matching key exists in component: ir.sabaap.jahadattendancesystem.di.component.LoginActivityComponent

问题是什么？ :-(

AppComponent.java：

 @Singleton
 @Component(modules = {AndroidInjectionModule.class, ActivityBuilder.class, AppModule.class,
    ViewModelFactoryModule.class})
  public interface AppComponent {
       @Component.Builder
       interface Builder {
          @BindsInstance
          Builder application(Application application);
          AppComponent build();
}
   void inject(App app);
}

ActivityBuilder.java：

@Module
public abstract class ActivityBuilder {
// main activity
 @Binds
 @IntoMap
 @ActivityKey(MainActivity.class)
 abstract AndroidInjector.Factory<? extends Activity> 
 bindMainActivity(MainActivityComponent.Builder builder);

// login activity
 @Binds
 @IntoMap
 @ActivityKey(LoginActivity.class)
 abstract AndroidInjector.Factory<? extends Activity> 
 bindLoginActivity(LoginActivityComponent.Builder builder);


}

FragmentBuilder.java：

 @Module
 public abstract class FragmentBuilder {
   //bind fragments ;
   @Binds
   @IntoMap
   @FragmentKey(BarCodeFragment.class)
   abstract AndroidInjector.Factory<? extends Fragment> bindBarcodeFragment( BarcodeFragmentComponent.Builder builder);

   @Binds
   @IntoMap
   @FragmentKey(AddressManager.class)
   abstract AndroidInjector.Factory<? extends Fragment> bindAddressFragment(AddressManagerFragmentComponent.Builder builder);

   @Binds
   @IntoMap
   @FragmentKey(LoginFragment.class)
   abstract AndroidInjector.Factory<? extends Fragment> bindLoginFragment(LoginFragmentComponent.Builder builder);

   }

LoginFragmentComponent.java：

 @Subcomponent(modules = {LoginFragmentModule.class , LoginFragmentViewModelModule.class})
 public interface LoginFragmentComponent extends AndroidInjector<LoginFragment> {
   @Subcomponent.Builder
   abstract class Builder extends AndroidInjector.Builder<LoginFragment>{}
 }

LoginActivityComponent.java：

 @Subcomponent(modules = {LoginActivityModule.class, LoginActivityViewModelModule.class, FragmentBuilder.class})
 public interface LoginActivityComponent extends AndroidInjector<LoginActivity> {
   @Subcomponent.Builder
   abstract class Builder extends AndroidInjector.Builder<LoginActivity> {}

}

AppModule.java：

 @Module(subcomponents = {MainActivityComponent.class, LoginActivityComponent.class})
 public class AppModule {
   @Singleton
   @Provides
   OkHttpClient.Builder provideOkHttp(HttpLoggingInterceptor interceptor,
                                   PersistentCookieJar persistentCookieJar) {
       final OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
       httpClient.connectTimeout(8, TimeUnit.SECONDS);
       httpClient.readTimeout(8, TimeUnit.SECONDS);
       httpClient.callTimeout(8, TimeUnit.SECONDS);
       httpClient.cookieJar(persistentCookieJar);
       httpClient.addInterceptor(interceptor);
       return httpClient;
   }

   ... //other methods 
 }

LoginActivity.java：

   public class LoginActivity extends BaseActivity implements 
   HasSupportFragmentInjector {
   @Inject
   DispatchingAndroidInjector<Fragment> fragmentDispatchingAndroidInjector;

   @Inject
   SharedPreferences sharedPreferences;

   @Override
   public void onCreate(@Nullable Bundle savedInstanceState) {
    AndroidInjection.inject(this);
    ((App) getApplication()).setActivity(this);
    super.onCreate(savedInstanceState);
   }

   @Override
   protected int getContentView() {
       return R.layout.content_main;
   }

   @Override
   protected boolean requestFullScreenActivity() {
       return true;
   }

   @Override
   protected void init() {

       setLocalDirection();

       boolean address_def = sharedPreferences.getBoolean("address_def", false);

       if (address_def)
           attachFragment(new LoginFragment());
       else
           attachFragment(new AddressManager());

   }

   @Override
   protected int toolbarMenu() {
       return 0;
   }

   public void attachFragment(Fragment fragment) {
       FragmentTransaction transaction = 
  getSupportFragmentManager().beginTransaction();
       transaction.replace(R.id.nav_host_fragment, fragment);
       transaction.commit();
   }

   @Override
   public void setLocalDirection() {

   }

   @Override
   public DispatchingAndroidInjector<Fragment> 
   supportFragmentInjector() {
       return fragmentDispatchingAndroidInjector;
   }

}

Answer 1

也许它只是从问题中省略了，但是片段子组件LoginFragmentComponent 是在MainActivityComponent 的一个@Module(subcomponent = ...) 下声明的吗？

信息A binding with matching key exists in component 是说LoginFragmentComponent.Builder 可以在LoginActivityComponent 中提供，但不能单独在AppComponent 或MainActivity 中提供。

The guide of Dagger-Android 建议在声明@Binds @IntoMap @ClassKey(...) 方法的同一模块中列出@Module.subcomponents：

@Module(subcomponents = YourActivitySubcomponent.class)
abstract class YourActivityModule {
  @Binds
  @IntoMap
  @ClassKey(YourActivity.class)
  abstract AndroidInjector.Factory<?>
      bindYourAndroidInjectorFactory(YourActivitySubcomponent.Factory factory);
}

@Module(subcomponents = YourFragmentSubcomponent.class)
abstract class YourFragmentModule {
  @Binds
  @IntoMap
  @ClassKey(YourFragment.class)
  abstract AndroidInjector.Factory<?>
      bindYourFragmentInjectorFactory(YourFragmentSubcomponent.Factory factory);
}

对于您的情况，在 ActivityBuilder 和 FragmentBuilder 模块中添加 @Module(subcomponents = ...) 以确保它们永远不会被遗忘。