Question

我还有一个根组件：

@Singleton
@Component(modules = [AndroidInjectionModule::class,
        AndroidSupportInjectionModule::class, 
        ActivityBuilderModule::class])
interface RootComponent : AndroidInjector<DaggerApplication> {
    fun inject(myApplication: MyApplication)
    override fun inject(photoPartyApplication: DaggerApplication)

    @Component.Builder
    interface Builder {
        @BindsInstance
        fun application(application: Application): Builder
        fun build(): RootComponent
    }
}

在ActivityBuilderModule中：

@Module
abstract class ActivityBuilderModule {

    @ContributesAndroidInjector(modules = [MainActivityModule::class,
            ViewModelModule::class])
    @ActivityScope
    abstract fun bindMainActivity(): MainActivity

    @ContributesAndroidInjector(modules = [SecondaryActivityModule::class,
            ViewModelModule::class,
            FragmentBuilderModule::class])
    @ActivityScope
    abstract fun bindSecondaryActivity(): SecondaryActivity

}

ViewModelModule是一个简单的模块，可帮助在ViewModel类中进行构造函数注入，并且由特定实例和@Binds类型之间的ViewModel组成。

MainActivityModule和SecondaryActivityModule为相应的活动定义特定的依赖关系。

关键是，当我添加此 FragmentBuilderModule 时-编译开始发出错误。堆栈跟踪是下一个：

错误：[Dagger / MissingBinding] some_package。如果没有@Inject构造函数或@Provides注释的方法，则无法提供SpecificDependency。

公共抽象接口RootComponent扩展了dagger.android.AndroidInjector {

^

组件中存在带有匹配键的绑定：some_package.ActivityBuilderModule_BindMainActivity.MainActivitySubcomponent

some_package.SpecificDependency注入到some_package.MainViewModel（specificDependency，…）

some_package.MainViewModel被注入到some_package.ViewModelModule.mainViewModel（viewModel）
Map<Class<? extends ViewModel>, Provider<ViewModel>> is injected at
      some_package.ViewModelFactory(viewModelProviders)
some_package.ViewModelFactory被注入到some_package.ViewModelModule.bindViewModelFactory（factory）

android.arch.lifecycle.ViewModelProvider.Factory被注入some_package.MyFragment.viewModelFactory

some_package.MyFragment被注入dagger.android.AndroidInjector.inject（T）

[some_package.RootComponent→some_package.ActivityBuilderModule_BindSecondaryActivity.SecondaryActivitySubcomponent→some_package.FragmentBuilderModule_ProvideMyFragmentFactoryMyFragmentSubcomponent]

据我了解，Dagger假设必须为map的{{1}}正确地构建整个依赖关系图，如果某些Class<? extends ViewModel> -> Provider<ViewModel>落入{{1} }，并且将ViewModels注入到组件中，那么如果该组件要求任何 factory，则必须将其交付。同样，为了交付所有factory，所有依赖项都必须可用（这是不正确的，因为viewmodel的特定依赖项仅可从viewmodels获得，这就是匕首在堆栈跟踪之前说。）

有没有解决方法，可以根据需要提供对MainViewModel的{{1}}的依赖关系，而不是在编译时构建整个图形（这会导致编译时错误）

Answer 1

首先在RootComponent上添加ViewModelModule

 @Singleton
 @Component(modules = [AndroidInjectionModule::class,
            AndroidSupportInjectionModule::class, 
            ActivityBuilderModule::class,
            ViewModelModule::class])                 // add this so you don't have to add for every activity
    interface RootComponent : AndroidInjector<DaggerApplication> {
        fun inject(myApplication: MyApplication)
        override fun inject(photoPartyApplication: DaggerApplication)

        @Component.Builder
        interface Builder {
            @BindsInstance
            fun application(application: Application): Builder
            fun build(): RootComponent
        }
    }

现在在ActivityBuilderModule中仅添加活动

 @Module
 abstract class ActivityBuilderModule {

    @ContributesAndroidInjector
    @ActivityScope
    abstract fun bindMainActivity(): MainActivity
 }

现在在ViewModelModule中添加所有ViewModel

 @Module
 abstract class ViewModelModule {

    @Binds
    @IntoMap
    @ViewModelKey(MainActivityModule::class)
    abstract fun bindMainActivityViewModel(mainActivityViewModel: MainActivityModule): ViewModel
}

添加ViewModelKey

 @MustBeDocumented
 @kotlin.annotation.Target(AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER)
 @kotlin.annotation.Retention(AnnotationRetention.RUNTIME)
 @MapKey
 internal annotation class ViewModelKey(val value: KClass<out ViewModel>)

和ViewModelFactory

@Singleton
class KotlinViewModelFactory @Inject
constructor(private val creators: Map<Class<out ViewModel>, @JvmSuppressWildcards Provider<ViewModel>>) : ViewModelProvider.Factory {

    @Suppress("UNCHECKED_CAST")
    override fun <T : ViewModel> create(modelClass: Class<T>): T {
        var creator: Provider<out ViewModel>? = creators[modelClass]
        if (creator == null) {
            for ((key, value) in creators) {
                if (modelClass.isAssignableFrom(key)) {
                    creator = value
                    break
                }
            }
        }
        if (creator == null) {
            throw IllegalArgumentException("unknown model class $modelClass")
        }
        try {
            Timber.d(creator.toString())
            return creator.get() as T
        } catch (e: Exception) {
            throw RuntimeException(e)
        }
    }
}

定义片段的注入器时，MVVM Factory中的Dagger2编译错误

1 个答案: