如何检测scrollView滚动方向？ [英] How to detect scrollView scrolling direction?

问题描述

我有一个 UIScrollView 里面有一个 UITableView 滚动视图应该水平滚动。我已经实现了 - （void）scrollViewDidEndDecelerating：（UIScrollView *）scrollView 在滚动视图结束其水平滚动时执行某些任务。但我的问题是，即使 UITableView 垂直滚动也停止，此委托也会触发。那么如何在这个代表中只检测 scrollview 水平滚动？

I have a UIScrollView inside that I have a UITableView The scroll view should scrol horizontally. And I have implemented - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView to do some tasks when the scroll view end its horizontal scrolling. But My problem is, this delegate is firing even when the UITableView vertical scrolling stopped too. So how can I detect just the scrollview horizontal scrolling within this delegate?

请帮助我，
谢谢

Please help me, Thanks

推荐答案

检查这些委托方法

CGPoint _lastContentOffset;

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
  _lastContentOffset = scrollView.contentOffset;
}

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

    if (_lastContentOffset.x < (int)scrollView.contentOffset.x) {
      NSLog(@"Scrolled Right");
    }
    else if (_lastContentOffset.x > (int)scrollView.contentOffset.x) {
      NSLog(@"Scrolled Left");
    }

    else if (_lastContentOffset.y < scrollView.contentOffset.y) {
      NSLog(@"Scrolled Down");
    }

    else if (_lastContentOffset.y > scrollView.contentOffset.y) {
      NSLog(@"Scrolled Up");
    }
}

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