UIScrollView 的代理方法简单注解

//减速停止了时执行，手触摸时执行执行
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView;
//只要滚动了就会触发

- (void)scrollViewDidScroll:(UIScrollView *)scrollView;

//开始拖拽视图
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView;

//完成拖拽
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate;

//将开始降速时
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView;

//滚动动画停止时执行,代码改变时出发,也就是setContentOffset改变时
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView;

//设置放大缩小的视图，要是uiscrollview的subview
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView;

//完成放大缩小时调用
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale;

//如果你不是完全滚动到滚轴视图的顶部，你可以轻点状态栏，那个可视的滚轴视图会一直滚动到顶部，那是默认行为，你可以通过该方法返回NO来关闭它
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView;

//视图滚动到看顶部会触发
- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView;