一、滑倒到顶部或底部不可滑动

CGPointoffset = scrollView.contentOffset;//scrollview当前显示区域定点相对于fram顶点的偏移量

CGRectbounds = scrollView.bounds;//原点

CGSizesize = scrollView.contentSize;//scrollview可以滚动的区域

UIEdgeInsetsinset = scrollView.contentInset;//scrollview的contentview的顶点相对于scrollview的位置

CGFloatcurrentOffset = offset.y+ bounds.size.height- inset.bottom;

CGFloatmaximumOffset = size.height;

if(offset.y <=0) {

    scrollView.contentOffset =CGPointMake(0,0);

}

if(currentOffset >= maximumOffset) {//滑倒底部

    scrollView.contentOffset=CGPointMake(0, maximumOffset - bounds.size.height);

    return;

}