如何判断ScrollView滑动方向

1/判断滚动视图左右滚动

   {
　   CGFloat startContentOffsetX;//滚动开始的坐标
    CGFloat willEndContentOffsetX; //滚动即将停止的坐标
    CGFloat endContentOffsetX;//滚动结束的坐标

　}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
    myPC.currentPage = scrollView.contentOffset.x / scrollView.frame.size.width;
    currNum = (int)myPC.currentPage;
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
     startContentOffsetX = scrollView.contentOffset.x;
    [self stopTimer];
}

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{    //将要停止前的坐标
    willEndContentOffsetX = scrollView.contentOffset.x;
}

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

    endContentOffsetX = scrollView.contentOffset.x;

    if (endContentOffsetX < willEndContentOffsetX && willEndContentOffsetX < startContentOffsetX) { //画面从右往左移动，前一页
        isNext = NO;
    } else if (endContentOffsetX > willEndContentOffsetX && willEndContentOffsetX > startContentOffsetX) {//画面从左往右移动，后一页
        isNext = YES;
    }
    [self starTimer];
}

2/判断上下滚动视图上下滚动

float lastContentOffset;
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    lastContentOffset = scrollView.contentOffset.y;
}

- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
    if (lastContentOffset < scrollView.contentOffset.y) {
        NSLog(@"向上滚动");
    }else{
        NSLog(@"向下滚动");
    }
}