Question

此代码在Java中完美运行，但在Kotlin中存在未定义的问题

问题：

  错误：[Dagger / MissingBinding]如果没有@Inject构造函数或@Provides注释的方法，则无法提供ru.terrakok.cicerone.Router。       公共抽象无效注入（@ org.jetbrains.annotations.NotNull（）

ru.terrakok.cicerone.Router在以下位置注入             com.setname.dagger2ciceronelearning.presentation.main.MainActivity.mRouter

com.setname.dagger2ciceronelearning.presentation.main.MainActivity在以下位置注入             com.setname.dagger2ciceronelearning.di.AppComponent.inject（com.setname.dagger2ciceronelearning.presentation.main.MainActivity）

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AppComponent

@Singleton
@Component(modules = arrayOf(NavigationModule::class))
interface AppComponent {

    fun inject(mainActivity: MainActivity)
    fun inject(fragmentOne: FragmentOne)
    fun inject(fragmentTwo: FragmentTwo)

}

NavigationModule

@Module
class NavigationModule {

    private val firstLevelNavigation: Cicerone<Router> = Cicerone.create()
    private val secondLevelNavigation: Cicerone<Router> = Cicerone.create()

    @Provides
    @Singleton
    @Named(Navigation.ROUTER_FIRST_LEVEL)
    fun provideFirstLevelRouter(): Router = firstLevelNavigation.router

    @Provides
    @Singleton
    @Named(Navigation.ROUTER_SECOND_LEVEL)
    fun provideSecondLevelRouter(): Router = secondLevelNavigation.router

    @Provides
    @Singleton
    @Named(Navigation.NAV_HOLDER_FIRST_LEVEL)
    fun provideFirstLevelNavigatorHolder(): NavigatorHolder = firstLevelNavigation.navigatorHolder


    @Provides
    @Singleton
    @Named(Navigation.NAV_HOLDER_SECOND_LEVEL)
    fun provideSecondLevelNavigationHolder(): NavigatorHolder = secondLevelNavigation.navigatorHolder

}

LearingApp

class LearningApp : Application() {

    companion object {

        lateinit var appComponent: AppComponent

    }

    override fun onCreate() {
        super.onCreate()
        appComponent = DaggerAppComponent
            .builder()
            .build()
    }

}

MainActivity

class MainActivity : AppCompatActivity() {

    @Inject
    @Named(Navigation.ROUTER_FIRST_LEVEL)
    lateinit var mRouter: Router

    @Inject
    @Named(Navigation.NAV_HOLDER_FIRST_LEVEL)
    lateinit var mNavigatorHolder: NavigatorHolder

    private lateinit var mNavigator:Navigator

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        LearningApp.appComponent.inject(this)

        mNavigator = SupportAppNavigator(this, R.id.main_container)

        mRouter.newRootScreen(Screens.FragmentOneScreen())

    }

    override fun onResume() {
        super.onResume()
        mNavigatorHolder.setNavigator(mNavigator)
    }

    override fun onPause() {
        mNavigatorHolder.removeNavigator()
        super.onPause()
    }

}

Answer 1

一个非常有智慧的人曾经说过：You need to target the annotation at the field by using @field:Named.

Answer 2

您可以尝试使用自定义限定词：

 subject_id first_name_x last_name_x first_name_y last_name_y
0          2          Amy    Ackerman          Amy    Ackerman
1          4        Alice        Aoni        Billy      Bonder

然后您的模块：

@Qualifier
@Retention
annotation class RouterFirstLevel

和活动：

@Provides
@Singleton
@RouterFirstLevel
fun provideFirstLevelRouter(): Router = firstLevelNavigation.router

P.S。我同意jbarat的观点，注解中的字段应该有所帮助，请尝试使用字符串代替字符串常量，也许某些类型不匹配

匕首2，Cicerone，科特林-注入问题

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2 个答案: