Question

我已经尝试过创建多个组件。首先将存储应用程序的主要部分，例如ViewModel的结构，上下文和其他设置。其他组件-每个屏幕的组件。因此，f.ex。我有FirstScreen。我试图用其ViewModel创建组件：

@Subcomponent(modules = [StoreModule::class])
@StoreScope
interface StoreComponent {

    fun inject(activity: MainActivity)

    fun inject(fragment: StoreFragment)

    @Subcomponent.Builder
    interface Builder {

        fun build(): StoreComponent

    }

}

因此，StoreViewModel作为其依赖项StoreRepository内置在StoreComponent的模块中：

@Module
abstract class StoreModule {

    @Binds
    @IntoMap
    @ViewModelKey(StoreViewModelImpl::class)
    abstract fun getStoreViewModel(viewModel: StoreViewModelImpl): ViewModel

    @Binds
    @StoreScope
    abstract fun getStoreRepository(repository: StoreRepositoryImpl): StoreRepository

}

这是AppComponent：

@Component(modules = [
    GsonModule::class,
    RetrofitModule::class,
    ViewModelsFactoryModule::class,
    CiceroneModule::class
])
@Singleton
interface AppComponent {

    fun getStoreComponentBuilder(): StoreComponent.Builder

}

在这里建立ViewModel的工厂：

@Module
abstract class ViewModelsFactoryModule {

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


    @Binds
    abstract fun getViewModelFactory(factory: ViewModelFactory): ViewModelProvider.Factory

}

但是，当我尝试构建项目时，出现了错误，没有@ Provides-annonated方法，匕首无法将Map<java.lang.Class<? extends android.arch.lifecycle.ViewModel>提供给ViewModelFactory-class。

error: [com.sagrishin.smartreader.di.components.StoreComponent.inject(com.sagrishin.smartreader.presentation.fragments.StoreFragment)] java.util.Map<java.lang.Class<? extends android.arch.lifecycle.ViewModel>,javax.inject.Provider<android.arch.lifecycle.ViewModel>> cannot be provided without an @Provides-annotated method.
public abstract interface AppComponent {
                ^
      java.util.Map<java.lang.Class<? extends android.arch.lifecycle.ViewModel>,javax.inject.Provider<android.arch.lifecycle.ViewModel>> is injected at
          com.sagrishin.smartreader.presentation.viewmodels.factory.ViewModelFactory.<init>(creators)
      com.sagrishin.smartreader.presentation.viewmodels.factory.ViewModelFactory is injected at
          com.sagrishin.smartreader.presentation.fragments.StoreFragment.viewModelsFactory
      com.sagrishin.smartreader.presentation.fragments.StoreFragment is injected at
          com.sagrishin.smartreader.di.components.StoreComponent.inject(fragment)

UPD：viewmodel工厂：

typealias ViewModelsProvidersMap =
        Map<Class<out ViewModel>, @JvmSuppressWildcards Provider<ViewModel>>


@Singleton
class ViewModelFactory : ViewModelProvider.Factory {

    private val creators: ViewModelsProvidersMap

    @Inject
    constructor(creators: ViewModelsProvidersMap) {
        this.creators = creators
    }

    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 {
            return creator.get() as T
        } catch (e: Exception) {
            throw RuntimeException(e)
        }

    }
}

Answer 1

通过将ViewModelFactory.kt和ViewModelsFactoryModule.kt切换到Java，我解决了同样的问题。

ViewModelFactory.java

@Singleton
public class ViewModelFactory implements ViewModelProvider.Factory {
    private final Map<Class<? extends ViewModel>, Provider<ViewModel>> creators;

    @Inject
    ViewModelFactory(Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
        this.creators = creators;
    }

    @NonNull
    @SuppressWarnings("unchecked")
    @Override
    public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
        Provider<? extends ViewModel> creator = creators.get(modelClass);
        if (creator == null) {
            for (Map.Entry<Class<? extends ViewModel>, Provider<ViewModel>> entry : creators.entrySet()) {
                if (modelClass.isAssignableFrom(entry.getKey())) {
                    creator = entry.getValue();
                    break;
                }
            }
        }
        if (creator == null) {
            throw new IllegalArgumentException("unknown model class " + modelClass);
        }
        try {
            return (T) creator.get();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

ViewModelsFactoryModule.java

@Module
abstract class ViewModelModule {

    @NonNull
    @Binds
    @IntoMap
    @ViewModelKey(StoreViewModelImpl.class)
    abstract ViewModel bindLauncherViewModel(StoreViewModelImpl viewModel);

    @NonNull
    @Binds
    abstract ViewModelProvider.Factory bindViewModelFactory(ViewModelFactory viewModelFactory);
}

Answer 2

您不必切换到Java，只需使用kotlin 1.3.31对其进行修复。 https://github.com/google/dagger/issues/1478#issuecomment-486712176

包括以下Jvm注释

Map<Class<out ViewModel>, @JvmSuppressWildcards Provider<ViewModel>>

Answer 3

No need to use @JvmSuppressWildcards. As the day of my Post my Kotlin version
 is : '1.3.40'

 Use dagger dependency in build.gradle

 apply plugin: 'kotlin-kapt'

 //Dagger dependencies
implementation 'com.google.dagger:dagger:2.22.1'
kapt 'com.google.dagger:dagger-compiler:2.22.1'

implementation 'com.google.dagger:dagger-android:2.22'
implementation 'com.google.dagger:dagger-android-support:2.22' // if you use the support libraries
kapt 'com.google.dagger:dagger-android-processor:2.22'


And for Java use the following dagger dependency

 //Dagger dependencies
implementation 'com.google.dagger:dagger:2.22.1'
annotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'

implementation 'com.google.dagger:dagger-android:2.22'
implementation 'com.google.dagger:dagger-android-support:2.22' // if you use the support libraries
annotationProcessor 'com.google.dagger:dagger-android-processor:2.22'

Answer 4

您的依赖版本可能有所不同，例如您的核心/编译器版本为2.22或其他版本，但您的android版本为2.16，这也可能导致异常，请执行以下操作：
从这个

    implementation 'com.google.dagger:dagger:2.22'
    kapt 'com.google.dagger:dagger-compiler:2.22'
    // For android
    implementation 'com.google.dagger:dagger-android:2.16'
    implementation 'com.google.dagger:dagger-android-support:2.16'
    // if you use the support libraries
    kapt 'com.google.dagger:dagger-android-processor:2.16'

对此

 //Dagger 2
    implementation 'com.google.dagger:dagger:2.22'
    kapt 'com.google.dagger:dagger-compiler:2.22'
    // For android
    implementation 'com.google.dagger:dagger-android:2.22'
    implementation 'com.google.dagger:dagger-android-support:2.22'
    // if you use the support libraries
    kapt 'com.google.dagger:dagger-android-processor:2.22'

匕首：无法提供Map <java.lang.class <？ extend =“” android.arch.lifecycle.viewmodel =“”>，而没有@Provides注释的方法

4 个答案: