iphone - UIScrollView 委托方法冲突

Question

我正在使用以下两个 UIScrollView 委托方法来调用我的 UIViewController 中的另一个方法：

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    // do something
}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
    // do something
}

我尝试了各种不同的调用//做某事的方法，但要么最终都没有被调用，要么两个委托方法都被调用，在某些情况下调用 //do something 两次。例如：

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    if(![scrollView isDecelerating] && ![scrollView isDragging]){
        //do something
    }
}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
    if(!decelerate){
        //do something
    }
}

因此，如果我滚动并让它减速停止，它会调用scrollViewDidEndDecelerating：，但如果我通过点击滚动并停止它，它会调用scrollViewDidEndDragging：和scrollViewDidEndDecelerating：

我希望它调用一个或另一个......我可以用 scrollViewDidEndDecelerating: 和 scrollView 对象来停止这个双重方法调用吗？

Answer 1

The scroll view delegate does its job. You can not prevent it from happening. But with a simple logic you can achieve what you are trying to do.

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {

    dragged = YES;
    // do something
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

    if (!dragged) {

         // do something
    }

    dragged = NO;
}

Answer 2

// 很简单

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {

    if(!decelerate){
         // Do something 
    }

}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
       // Do something 
}

Answer 3

这似乎有效。接近EmptyStack 的答案

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

    if (!dragged) {
        //do something
    }

    dragged = NO;
}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{

    if(!decelerate){
        dragged = YES;
        //do something
    } else {
        dragged = NO;
    }
}