[ios]ios开发之检测UIScrollView的滚动方向 【转】

来自：http://blog.csdn.net/caryaliu/article/details/7907196

 int _lastPosition=0;

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
    int currentPostion = scrollView.contentOffset.y;
    if (currentPostion - _lastPosition > 25) {
        _lastPosition = currentPostion;
        NSLog(@"ScrollUp now");
    }
    else if (_lastPosition - currentPostion > 25)
    {
        _lastPosition = currentPostion;
        NSLog(@"ScrollDown now");
    }
}
25 可以是任意数字，可根据自己的需要来设定。