我正在尝试编写MVP模式的接口和默认实现。但是，我收到我认为应该可行的错误消息。我收到的错误消息是：
required: CAP#1
found: MVPPresenter<M,V>
reason: actual argument MVPPresenter<M,V> cannot be converted to CAP#1 by method invocation conversion
where V,M,P are type-variables:
V extends IMVPView< ? extends IMVPPresenter< ?,V>> declared in class MVPPresenter
M extends Object declared in class MVPPresenter
P extends IMVPPresenter< ?,? extends IMVPView< P>> declared in interface IMVPView
where CAP#1 is a fresh type-variable:
CAP#1 extends IMVPPresenter< ?,V> from capture of ? extends IMVPPresenter< ?,V>
这对我来说没有意义，因为MVPPresenter应该是CAP＃1。有人可以解释为什么我不能这样做或提供解决问题的方法吗？
/**
* Interface for the presenter in MVP
*
* @param <M> Model type
* @param <V> View type
*/
public interface IMVPPresenter<M, V extends IMVPView<? extends IMVPPresenter<?, V>>> {
...
}
/**
* Interface for the view in MVP
*
* @param <P> Presenter type
*/
public interface IMVPView<P extends IMVPPresenter<?, ? extends IMVPView<P>>> {
...
public void setPresenter(P presenter);
}
/**
* Default implementation of the presenter interface
*
* @param <M> Model Type
* @param <V> View Type
*/
public class MVPPresenter<M, V extends IMVPView<? extends IMVPPresenter<?, V>>>
implements IMVPPresenter<M, V> {
...
protected void setView(V view) {
...
view.setPresenter(this); // Error on this line
}
}
具体的课程必须……具体得多。
public class MVPPresenter<M, V extends IMVPView<MVPPresenter<M,V>>>
implements IMVPPresenter<M, V> {
protected void setView(V view) {
view.setPresenter(this); // No more error on this line
}
}
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我来说两句