draggingEntered:调用但performDragOperation:不在IKImageBrowserView上

Question

我正在使用IKImageBrowserView设置下拉删除

[self.imageBrowserView setDraggingDestinationDelegate:self];

无论我在draggingEntered中返回了什么: performDragOperation: gets从未调用

- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender {
    // GETS CALLED 
    return NSDragOperationEvery;
}

- (BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender {
    // NOT CALLED
    return YES;
}

- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
    // NOT CALLED
    return YES;
}

Answer 1

显然，draggingUpdated:必须实现。