Question

我正在Kotlin中实现MVP架构，并且Android Studio没有显示错误，但是无法编译：

java.lang.AssertionError：ResultingDescriptor不应为null：候选人描述符：构造函数BasePresenter（view：视图）在com.exmaple.base.BasePresenter替换中定义： org.jetbrains.kotlin.types.IndexedParametersSubstitution@70144d7e位于 org.jetbrains.kotlin.resolve.calls.model.ResolvedCallImpl.setResultingSubstitutor（ResolvedCallImpl.java:205） ....

是否可以在继承过程中使用ConcreteView / ConcretePresenter？

代码：

/**
 * These are the base classes
 */
interface MvpView

interface BaseView<Presenter : BasePresenter<*>> : MvpView, HasMvpView<MvpView>

// to avoid circular dependency
interface HasMvpView<View : MvpView> 

abstract class BaseMvpActivity<Presenter : BasePresenter<*>> : AppCompatActivity(), HasMvpView<MvpView>

abstract class BaseMvpFragment<Activity : BaseMvpActivity<*>, Presenter : BasePresenter<*>>: Fragment(), HasMvpView<MvpView> {
        // this will cause the error
        abstract var presenter: Presenter
}


/**
 * There's a Viewpager, and each page looks the same the only difference is their source of data. That's why I tried implementing another level of abstraction over the base classes
 */
interface CategoryPagerView<Presenter: BasePresenter<*>> : BaseView<Presenter>

abstract class CategoryPagerFragment: BaseMvpFragment<LandingActivity, BasePresenter<*>>()

/**
 * A concrete type of the Viewpager's fragment, its presenter and the view
 */
interface ConcreteView : CategoryPagerView<ConcretePresenter> 

class ConcretePresenter(view: ConcreteView) : BasePresenter<*>(view)

class ConcreteFragment : CategoryPagerFragment(), ConcreteView {
        // this line shows no error in the IDE, but in compile time
        override var presenter = ConcretePresenter(this)

感谢您的帮助！

Answer 1

这是编译器抛出的内部声明错误。您可以在此处看到编译器源代码：

https://github.com/JetBrains/kotlin/blob/master/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/model/ResolvedCallImpl.java

显然，resultingDescriptor在null上永远是null。因此，这似乎是一个编译器错误。也许应该在Kotlin中将其重写以避免null出现问题：）

请在https://youtrack.jetbrains.com/issues/KT

提交错误报告

如何使用泛型类解决第二级继承？

1 个答案: