如果没有@Provides方法,则无法提供Dagger 2 Named

Question

试图找到Dagger 2并且遇到命名提供者的问题.我有一个简单的设置如下:

// Module
@Module
class AppModule(private val app: App) {
    @Provides @AppScope fun providesApp() = app

    @Provides @AppScope fun provideSharedPreferences(app: App) = PreferenceManager.getDefaultSharedPreferences(app)

    @Provides @AppScope @Named("Uri1") fun providesUri1() = Uri.Builder().scheme("https").authority("authory1").build()

    @Provides @AppScope @Named("Uri2") fun providesUri2() = Uri.Builder().scheme("https").authority("authory2").build()
}

// Component
@AppScope
@Component(modules = arrayOf(AppModule::class))
interface AppComponent {
    fun inject(target: MainActivity)
}

// MainActivity
@Inject @AppScope lateinit var preferences: SharedPreferences
@Inject @AppScope @Named("Uri1") lateinit var uri1: Uri
@Inject @AppScope @Named("Uri2") lateinit var uri2: Uri

在重建我的项目时,我得到了:

Error:Gradle: android.net.Uri cannot be provided without an @Provides- or @Produces-annotated method.

我不明白为什么在这里添加Named限定符对我不起作用.如果我删除这些,我可以得到一个SharedPreferences的实例没有问题.

任何洞察我做错的事都将不胜感激!

编辑:

每项建议的更改与上述结果相同.

// New module
@Module
class AppModule(private val app: App) {
    @Provides @AppScope fun providesApp() = app

    @Provides @AppScope fun provideSharedPreferences(app: App) = PreferenceManager.getDefaultSharedPreferences(app)

    @Provides @AppScope @Tag("Uri1") fun providesUri1(): Uri = Uri.Builder().scheme("https").authority("authority1").build()

    @Provides @AppScope @Tag("Uri2") fun providesUri2(): Uri = Uri.Builder().scheme("https").authority("authority2").build()
}

// Tag annotation
@Qualifier
@Retention(AnnotationRetention.RUNTIME)
annotation class Tag(val tag: String = "")

// MainActivity
@Inject @AppScope lateinit var preferences: SharedPreferences
@Inject @AppScope @Tag("Uri1") lateinit var uri1: Uri
@Inject @AppScope @Tag("Uri2") lateinit var uri2: Uri

Project Repo @ Github

Answer 1

我想我发现了问题(至少我检查了你的项目,它正确地生成了匕首类).如果您需要注入带注释的字段@Named或一些@Qualifier注释,您必须使用这种语法:

class MainActivity : AppCompatActivity() {
    @Inject lateinit var preferences: SharedPreferences
    @Inject @field:[Named ("Uri1")] lateinit var uri1: Uri // for @Named annotation or...
    @Inject @field:Uri2 lateinit var uri2: Uri // ...for @Qualifier annotation

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        app().component.inject(this)

        println(uri1)
        println(uri2)
    }
}

注意@Named/ qualifier注释是如何进入的@field:(没有@自身).

从这个回购借来的想法.