Question

我想在我的MVP模式中使用匕首，但当我调用函数时，lateinit Presenter不会初始化。主持人不是私人的。

这是我的匕首ViewModule，它为演示者提供活动作为视图

@Module
class ViewModule {

    @Provides
    fun provideAView(): AView = MainActivity()
}

PresenterModule

@Module
class PresenterModule {

    @Provides
    fun provideAPresenter(repo: ARepo, view: AView): APresenter = APresenter(repo, view)



}

RepoModule

@Module
class RepoModule {

    @Provides
    fun provideARepo(): ARepo = ARepo()
}

还有我的APresenter构造函数

class APresenter @Inject constructor(var repo: ARepo, var view: AView) {

    fun showHelloWorld() {
        val i = repo.repo()
        Log.d("main", "aPresenter repo : $i")
        view.helloWorld()
    }
}

组件

@Component(modules = [PresenterModule::class, RepoModule::class, ViewModule::class])
@Singleton
interface PresenterComponent {
    fun injectMain(view: AView)
}

MainActivity，它实现AView界面并注入演示者

class MainActivity : AppCompatActivity(), AView, BView {

    @Inject
    lateinit var aPresenter: APresenter


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

        val component = DaggerPresenterComponent.create()
        component.injectMain(this)

        // but this presenter will not init at this time and cause
        // lateinit property not init exception.
        aPresenter.showHelloWorld()
}

Answer 1

您需要在inject(...)接口的Component方法中指定确切的类型。否则，将不会注入成员。（有关更多说明，请参见此comment）

因此将您的组件类更改为：

@Component(modules = [PresenterModule::class, RepoModule::class, ViewModule::class])
@Singleton
interface PresenterComponent {
    fun injectMain(view: MainActivity) //<-- The AView is changed to MainActivity
}

Dagger2在活动中注入Lateinit var Presenter

1 个答案: