java.lang.RuntimeException：无法创建类 MovieViewModel 的实例，存储库尚未初始化

Question

当我注入 viewModel 和存储库时，它给了我这个错误，但我认为我做对了。

日志错误

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.apps.abousalem.movies/com.apps.abousalem.movies.ui.MainActivity}: kotlin.UninitializedPropertyAccessException: lateinit property repository has not been initialized
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2457)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2519)
    at android.app.ActivityThread.access$1200(ActivityThread.java:165)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1380)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5669)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
 Caused by: kotlin.UninitializedPropertyAccessException: lateinit property repository has not been initialized
    at com.apps.abousalem.movies.ui.base.BaseViewModel.getRepository(BaseViewModel.kt:11)
    at com.apps.abousalem.movies.ui.MoviesViewModel.<init>(MoviesViewModel.kt:13)
    at java.lang.reflect.Constructor.newInstance(Native Method)
    at java.lang.Class.newInstance(Class.java:1606)
    at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.java:196)
    at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:255)
    at androidx.lifecycle.ViewModelProvider$FactoryWrapper.create(ViewModelProvider.java:268)
    at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:179)
    at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:147)
    at com.apps.abousalem.movies.di.module.ActivityModule.provideMoviesViewModel(ActivityModule.kt:35)
    at com.apps.abousalem.movies.di.module.ActivityModule_ProvideMoviesViewModelFactory.proxyProvideMoviesViewModel(ActivityModule_ProvideMoviesViewModelFactory.java:27)
    at com.apps.abousalem.movies.di.module.ActivityModule_ProvideMoviesViewModelFactory.get(ActivityModule_ProvideMoviesViewModelFactory.java:18)
    at com.apps.abousalem.movies.di.module.ActivityModule_ProvideMoviesViewModelFactory.get(ActivityModule_ProvideMoviesViewModelFactory.java:8)
    at dagger.internal.DoubleCheck.get(DoubleCheck.java:47)
    at com.apps.abousalem.movies.di.component.DaggerMoviesActivityComponent.injectMainActivity(DaggerMoviesActivityComponent.java:55)
    at com.apps.abousalem.movies.di.component.DaggerMoviesActivityComponent.inject(DaggerMoviesActivityComponent.java:45)
    at com.apps.abousalem.movies.ui.MainActivity.onCreate(MainActivity.kt:28)
    at android.app.Activity.performCreate(Activity.java:6102)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2410)

这是一个ActivityModule，我提供ViewModel 活动模块

@Module
class ActivityModule(private val activity: AppCompatActivity){
@ActivityScope
@ActivityContext
@Provides
fun provideContext():Context{
    return activity
}
@ActivityScope
@ActivityContext
@Provides
fun provideActivity():AppCompatActivity{
    return activity
}
@ActivityScope
@Provides
fun provideMoviesViewModel(): MoviesViewModel {
    return ViewModelProviders.of(activity).get(MoviesViewModel::class.java)
}
@ActivityScope
@Provides
fun provideBaseViewModel(): BaseViewModel {
    return ViewModelProviders.of(activity).get(BaseViewModel::class.java)
}
}

在这里我提供Repository 类

应用模块

@Module
class ApplicationModule(var application: Application){

@ApplicationScope
@ApplicationContext
@Provides
fun provideContext(): Context {
    return application
}

@ApplicationScope
@ApplicationContext
@Provides
fun provideApplication(): Application {
    return application
}

@ApplicationScope
@Provides
fun getMovieDatabase(@ApplicationContext context: Application): MovieDatabase {
    return MovieDatabase.getInstance(context)
}

@ApplicationScope
@Provides
fun getSharedPreference(@ApplicationContext context: Context): SharedPreferences {
    return context.getSharedPreferences(MOVIES_PREFERENCE, Context.MODE_PRIVATE)
}

@ApplicationContext
@ApplicationScope
@Provides
fun getRepository(moviesApi: MoviesApi, movieDatabase: MovieDatabase, sharedPreferences: SharedPreferences): MoviesRepository {
    return MoviesRepository(moviesApi, movieDatabase, sharedPreferences)
}

}

我在这里注入它。

BaseViewModel

open class BaseViewModel: ViewModel(){
@Inject
lateinit var repository: MoviesRepository
}

我不明白为什么会发生这种情况为什么不能初始化repository和viewmodel

Answer 1

您将repository: MoviesRepository 注释为在注入时注入，但您似乎从未真正注入视图模型对象（ViewModelProviders 仅提供并且不进行注入）。

您可以在 dagger 组件类中添加 fun inject(viewModel: MyFinalViewModel) 使其可注入，然后调用 component.inject(viewModel) 注入它。
如果你不想注入视图模型（感觉有点显眼），请尝试在其构造函数中传递依赖项。