android - 如何解析具有不同作用域的绑定(bind)？

我有一个要用作单例的模型(AModel)。我创建了一个名为@ApplicationScope的自定义范围，以将其用于只需要使用一次的每个类。因此，AppComponent和AModel共享此@ApplicationScope。我有一些片段(ConfirmationFragment)，我想同时使用AModel和BModel。 BModel具有不同的范围，因为我想在3个片段中使用它，但是Amodel到处都需要。

访问AModel和BModel的想法是让ConfirmationComponent依赖于已经存在AModel的AppComponent。这样，如果我将ConfirmationComponent注入(inject)到ConfirmationFragment中，我也可以使用AModel。
但是我遇到了以下错误:[Dagger/IncompatiblyScopedBindings] ConfirmationComponent scoped with @ConfirmationScope may not reference bindings with different scopes:
当从ConfirmationFragment中注释掉注入(inject)AModel时，构建成功，但如果不是，则构建失败。我也需要该片段中的AModel。

我该如何解决这个问题？
(以防万一，这很重要:我只使用一个 Activity ，然后让Android导航对片段进行处理。)

open class MyApplication : Application() {
    override fun onCreate() {
        super.onCreate()
        val appComponent = initializeComponent()
    }

    val appComponent: AppComponent by lazy {
        initializeComponent()
    }

    val confirmationComponent: ConfirmationComponent by lazy {
        initializeConfirmationComponent()
    }

    open fun initializeComponent(): AppComponent {
        return DaggerAppComponent.factory().create(applicationContext)
    }

    open fun initializeConfirmationComponent(): ConfirmationComponent {
        return DaggerConfirmationComponent.builder().appComponent(appComponent).build()
    }
}

@ApplicationScope
@Component(modules = [NetworkModule::class])
interface AppComponent {
    @Component.Factory
    interface Factory {
        fun create(@BindsInstance context: Context) : AppComponent
    }
    fun inject(activity: MainActivity)
    fun inject(fragment: ConfirmationFragment)
}

@ConfirmationScope
@Component(dependencies = [AppComponent::class])
interface ConfirmationComponent {
    fun inject(fragment: ConfirmationFragment)
}

@ApplicationScope
class AModel @Inject constructor() {}

@ConfirmationScope
class BModel @Inject constructor() {}

class ConfirmationFragment : Fragment() {
    @Inject
    lateinit var modelA : AModel

    @Inject
    lateinit var modelB : BModel

    override fun onAttach(context: Context) {
        super.onAttach(context)
        (requireActivity().applicationContext as MyApplication).confirmationComponent.inject(this)
    }
    // Rest of the code
}

最佳答案

我认为您应该将其改写。如果我正确地理解了您，那么ModelA的范围比ModelB的范围大，这意味着您可以将ModelB作为ModelA的子组件，范围更窄。

因此，您需要:

ConfirmationComponent

//@YourScopeAnnotation
@Subcomponent(modules = [...]) // if it is dependent on any modules
interface ConfirmationComponent {

    // needed for dagger to create component
    @Subcomponent.Factory
    interface Factory {
        fun create(): ConfirmationComponent
    }


    fun inject(yourFragment: Fragment) // fun inject your fragment
}

子组件模块

@Module(
    subcomponents = [ConfirmationComponent::class]
)
class SubcomponentsModule

在您的ApplicationComponent中

//@ApplicationScopeAnnotation  I think you can also use @Singleton
@Component(
    modules = [NetworkModule::class, SubcomponentsModule::class]
)
interface ApplicationComponent {

    fun inject(activity: MainActivity)
    fun confirmationComponent(): ConfirmationComponent.Factory

}

比照常只在您的Application类中初始化ApplicationComponent

现在在您的主要 Activity 中注入(inject)应该在全局范围内可用的ModelA。还要在 Activity

中创建ConfirmationComponent

@Inject
lateinit var modelA : AModel

lateinit var confirmationComponent: ConfirmationComponent

override fun onCreate(savedInstanceState: Bundle?) {
    confirmationComponent = (applicationContext as MyApplication).appComponent
            .confirmationComponent()
            .create()

    modelA = (applicationContext as MyApplication).appComponent.inject(this)

}

最后一步，在片段中注入(inject)modelB并从

Activity 中获取modelA

@Inject
    lateinit var modelB: ModelB // inject modelB

    lateinit var modelA: ModelA // get ModelA from activity where it was already injected

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        (activity as MainActivity).confirmationComponent.inject(this)

        modelA = (activity as MainActivity).modelA

    }

我希望这有帮助 :)