Kotlin 中带有扩展的泛型
Generics in Kotlin with extends
我正在尝试将 java 项目移植到 kotlin，但遇到了一些问题。我在 java 中使用泛型
有一些 MVP 结构
interface View<P extends Presenter> {}
interface Presenter<V extends View> {}
interface BaseView<P extends Presenter> extends View<P> {}
class BaseActivity<P extends Presenter> extends AppCompatActivity implements BaseView<P> {}
前两个 类 我有来自 IDE
的错误
interface Presenter<V : View<*>> {}
interface View<P : Presenter<*>> {}
我的错误是
*this type parameter violates the finite bound restriction*
Java 代码没有任何问题
我想这在 Kotlin 中是不允许的。
来自Kotlin spec：
The following pair of declarations is invalid, because there are edges
T → S and S → T, forming a cycle:
interface B<T : C<*>>
interface C<S : B<*>>
原因如下：
In its fully expanded form this bound would be infinite. The purpose
of this rule is to avoid such infinite types, and type checking
difficulties associated with them.
你的情况是V -> P 和P -> V 形成一个循环。
我正在尝试将 java 项目移植到 kotlin，但遇到了一些问题。我在 java 中使用泛型
有一些 MVP 结构interface View<P extends Presenter> {}
interface Presenter<V extends View> {}
interface BaseView<P extends Presenter> extends View<P> {}
class BaseActivity<P extends Presenter> extends AppCompatActivity implements BaseView<P> {}
前两个 类 我有来自 IDE
的错误interface Presenter<V : View<*>> {}
interface View<P : Presenter<*>> {}
我的错误是
*this type parameter violates the finite bound restriction*
Java 代码没有任何问题
我想这在 Kotlin 中是不允许的。
来自Kotlin spec：
The following pair of declarations is invalid, because there are edges T → S and S → T, forming a cycle:
interface B<T : C<*>>
interface C<S : B<*>>
原因如下：
In its fully expanded form this bound would be infinite. The purpose of this rule is to avoid such infinite types, and type checking difficulties associated with them.
你的情况是V -> P 和P -> V 形成一个循环。