Dagger 无法注入应用程序上下文

Question

我设置了 dagger 来管理片段和视图模型。我需要将应用程序上下文传递到我的视图模型，以便实例化并与存储库 class 通信。当我尝试这样做时，我从 dagger 中收到一条错误消息：

    error: [Dagger/DependencyCycle] Found a dependency cycle:
public abstract interface AppComponent {
                ^
      com.example.framework.BaseApplication is injected at
          com.example.di.AppModule.provideAppContext(application)
      com.example.framework.BaseApplication is injected at
          com.example.di.MainViewModelModule.provideMainViewModelFactory(application, �)
      androidx.lifecycle.ViewModelProvider.Factory is injected at
          com.example.framework.presentation.common.MainFragmentFactory(viewModelFactory)
      com.example.framework.presentation.common.MainFragmentFactory is injected at
          com.example.framework.presentation.main.MainActivity.fragmentFactory
      com.example.framework.presentation.main.MainActivity is injected at

我是 dagger 的新手，所以我很难确定此问题的根本原因以及如何实施修复。对这个问题中的代码量表示歉意，但匕首有许多 classes 可能是问题所在。

应用组件

@Component(
    modules = [
        AppModule::class,
        MainViewModelModule::class,
        MainFragmentFactoryModule::class
    ]
 )
 interface AppComponent {

 @Component.Builder
  interface Builder {

      @BindsInstance
      fun application(application: Application): Builder
      fun build(): AppComponent
  }

fun inject(mainActivity: MainActivity)

应用模块

@ExperimentalCoroutinesApi
@FlowPreview
@Module
object AppModule {

@JvmStatic
@Provides
@Singleton
fun provideAppContext(application: BaseApplication): BaseApplication{
    return application
}

查看模型模块

@ExperimentalCoroutinesApi
@FlowPreview
@Module
object MainViewModelModule {

@Singleton
@JvmStatic
@Provides
fun provideMainViewModelFactory(
        application: BaseApplication,
        editor: SharedPreferences.Editor,
        sharedPreferences: SharedPreferences
): ViewModelProvider.Factory{
    return MainViewModelFactory(
            application = application,
            editor = editor,
            sharedPreferences = sharedPreferences
    )
}

查看模型工厂

@FlowPreview
@ExperimentalCoroutinesApi
@Singleton
class MainViewModelFactory
@Inject
constructor(
    private val application: BaseApplication,
    private val editor: SharedPreferences.Editor,
    private val sharedPreferences: SharedPreferences
) : ViewModelProvider.Factory {

override fun <T : ViewModel> create(modelClass: Class<T>): T {
    return when(modelClass){

        ViewModelUsers::class.java -> {
            ViewModelUsers(
                    application = application,
                    editor = editor,
                    sharedPreferences = sharedPreferences
            ) as T
        }

查看模型

@ExperimentalCoroutinesApi
@FlowPreview
@Singleton
class ViewModelUsers
@Inject
constructor(
        application: BaseApplication,
        private val editor: SharedPreferences.Editor,
        sharedPreferences: SharedPreferences
): ViewModel() {
    private var repoUsers = RepoUsers(application)

Answer 1

修复它的方法有很多，但简单的方法是您应该更改为 BaseApplication 并删除 AppModule class 因为它已经由 @BindsInstance 注释提供

@Component(
    modules = [
        MainViewModelModule::class,
        MainFragmentFactoryModule::class
    ]
 )
 interface AppComponent {

 @Component.Builder
  interface Builder {

      @BindsInstance
      fun application(application: BaseApplication): Builder
      fun build(): AppComponent
  }

fun inject(mainActivity: MainActivity)

Answer 2

将存储库注入视图模型解决了这个问题，而不是尝试通过链传递应用程序上下文。

Dagger 无法注入应用程序上下文

Dagger failing to inject Application context

android

dagger-2