Question

我试图在Kotlin中使用匕首2进行依赖注入。我要创建的依赖图是

Application-> Activity -> Fragment 每个组件都提供了必要的绑定/提供程序。这是我当前的结构：

AppModule.kt

@dagger.Module 
abstract class AppModule {

@Binds
abstract fun bindContext(application: Application): Context

@Binds
abstract fun bindApplication(application : Application) : Application
}

AppComponent.kt

@Singleton
@Component(modules = arrayOf(AppModule::class, 
AndroidInjectionModule::class, 
ActivityBuilder::class))
interface AppComponent : 
AndroidInjector<FreedomGuardianApp> {

@Component.Builder
abstract class Builder : AndroidInjector.Builder<FreedomGuardianApp>()
}

ActivityModule.kt

@Module
abstract class ActivityBuilder {

@PerActivity
@ContributesAndroidInjector(modules = arrayOf(MainActivityModule::class))
abstract fun bindMainActivity() : MainActivity
}

MainActivityModule.kt

@Module(includes = 
arrayOf(WatchFaceFragmentModule::class))
class MainActivityModule {

@Provides
fun adapter(activity: MainActivity): MyPagesAdapter {
    return MyPagesAdapter(activity.supportFragmentManager)
}
}

WatchFaceFragmentModule.kt

@Module
abstract class WatchFaceFragmentModule {

@PerFragment
@ContributesAndroidInjector
abstract fun contributeWatchFaceFragment(): WatchFaceFragment
}

WatchFaceProvidersModule.kt

@Module
class WatchFaceProvidersModule {
@Provides
fun gestureDetector(fragment: WatchFaceFragment): GestureDetectorCompat {
    return GestureDetectorCompat(fragment.context, fragment)
}

@Provides
@Named("textToSpeak")
fun textToSpeak(fragment: WatchFaceFragment): String {
    return fragment.resources.getString(R.string.time_string)
}

@Provides
fun textToSpeech(fragment: WatchFaceFragment): TextToSpeech {
    return TextToSpeech(fragment.context, fragment)
}
}

我正在WatchFaceFragment中注入GestureDetectorCompat，String（textToSpeak），TextToSpeak。

这是错误：

    public abstract interface AppComponent extends dagger.android.AndroidInjector<com.medicalguardian.freedomguardian.FreedomGuardianApp> {
                ^
  A binding with matching key exists in component: com.medicalguardian.freedomguardian.di.WatchFaceFragmentModule_ContributeWatchFaceFragment.WatchFaceFragmentSubcomponent
      com.medicalguardian.freedomguardian.ui.fragment.WatchFaceFragment is injected at
          com.medicalguardian.freedomguardian.ui.MainActivity.watchFaceFragment
      com.medicalguardian.freedomguardian.ui.MainActivity is injected at
          dagger.android.AndroidInjector.inject(T) [com.medicalguardian.freedomguardian.di.AppComponent ? com.medicalguardian.freedomguardian.di.ActivityBuilder_BindMainActivity.MainActivitySubcomponent]

我的结构错了吗？我没有注入WatchFaceFragment的构造函数，因为它没有帮助。我也使用了Dagger支持（DaggerFragment，DaggerApplication等）。如果我不是注入片段而是仅注入MainActivity，那就很好。我该如何解决这个问题？冗长的阅读提前致歉。任何帮助表示赞赏。

Answer 1

您尚未向我们显示要在其中包含WatchFaceProvidersModule的位置，但是它应该包含在WatchFaceFragmentModule.kt的@ContributesAndroidInjector批注中，而不是包含在AppComponent或ActivityModule中：

@Module
abstract class WatchFaceFragmentModule {

  @PerFragment
  @ContributesAndroidInjector(modules = arrayOf(WatchFaceProvidersModule::class))
  abstract fun contributeWatchFaceFragment(): WatchFaceFragment
}

这应该确保在注入WatchFaceFragment实例（以及所需的GestureCompat等）时，您可以访问WatchFaceFragment实例。否则，如评论中提到的David所示，您的FreedomGuardianApp或MainActivity的注入器将不知道返回哪个WatchFaceFragment。一个可能还不存在。

匕首2：子组件

1 个答案: