Dagger2 - 多模块 - 组件中存在具有匹配键的绑定

Question

背景

我正在尝试在多模块设置中使用匕首。我的目标之一是减少使用的组件数量。所以基本上每个功能模块的目标是 1 个组件。

设置核心->应用->功能

问题

Dagger 失败，但 A binding with matching key exists in component: 异常，它指的是 I have bound a dependency somewhere in my entire object graph but it cannot be reached.

但是对于我的场景，我在我的活动中创建子组件并调用注入以确保该组件可以访问我的活动。这至少在我的理解中应该是可访问的，但它仍然无法提供我的视图模型的依赖关系。

这里是sample/multi-module，以防有人想尝试。

堆栈跟踪

/Users/feature1/build/**/FeatureComponent.java:8: error: [Dagger/MissingBinding]
com.**.FeatureActivity cannot be provided without an @Inject constructor or an @Provides-annotated 
method. This type supports members injection but cannot be implicitly provided.
public abstract interface FeatureComponent {
                ^
  A binding with matching key exists in component: com.**.FeatureComponent
      com.**.FeatureActivity is injected at
          com.**.FeatureModule.provideVM(activity)
      com.**.FeatureViewModel is injected at
          com.**.FeatureActivity.vm
      com.**.FeatureActivity is injected at
          com.**.FeatureComponent.inject(com.**.FeatureActivity)

应用组件

@AppScope
@Component(dependencies = [CoreComponent::class])
interface AppComponent {

    fun inject(app: MainApp)

    @Component.Factory
    interface Factory {
        fun create(
            coreComponent: CoreComponent
        ): AppComponent
    }
}

核心组件

@Singleton
@Component
interface CoreComponent {

    fun providerContext(): Context

    @Component.Factory
    interface Factory {
        fun create(
            @BindsInstance applicationContext: Context
        ): CoreComponent
    }
}

特征组件

@Component(
    modules = [FeatureModule::class],
    dependencies = [CoreComponent::class]
)
@FeatureScope
interface FeatureComponent {

    // Planning to use this component as a target dependency for the module.
    fun inject(activity: FeatureActivity)
}

功能模块

@Module
class FeatureModule {

    @Provides
    fun provideVM(activity: FeatureActivity): FeatureViewModel {
        val vm by activity.scopedComponent {
            FeatureViewModel()
        }
        return vm
    }
}

功能虚拟机

class FeatureViewModel @Inject constructor(): ViewModel() 

Answer 1

由于我使用activity 来提供我的viewModel，我将不得不使用@BindsInstance 来绑定我想要注入的任何活动或片段的实例。

简而言之，如果我将功能组件更改为以下代码，它就会开始工作，我在创建组件时绑定活动的实例。

PS：如果有人知道在后期只使用一个组件更好地注入片段，请随时改进此答案。

特征组件

@Component(
    modules = [FeatureModule::class],
    dependencies = [CoreComponent::class]
)
@FeatureScope
interface FeatureComponent {

    fun inject(activity: FeatureActivity)

    @Component.Factory
    interface Factory {
        fun create(
            @BindsInstance applicationContext: FeatureActivity,
            coreComponent: CoreComponent,
        ): FeatureComponent
    }
}