​​- (​​​​void​​​​)scrollViewDidScroll:(​​​​UIScrollView​​​ ​​*)aScrollView {​​
 

​​CGPoint​​​ ​​offset = aScrollView​​​​.contentOffset​​​​;​​


​​CGRect​​​ ​​bounds = aScrollView​​​​.bounds​​​​;​​


​​CGSize​​​ ​​size = aScrollView​​​​.contentSize​​​​;​​


​​UIEdgeInsets​​​ ​​inset = aScrollView​​​​.contentInset​​​​;​​


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


​​float​​​ ​​h = size​​​​.height​​​​;​​


​​float​​​ ​​reload_distance = -​​​​2​​​​0​​​​;​​


​​if​​​​(y > h + reload_distance) {​​


​​//距离到底 20 像素​​


​​}​​

 
 

​​}​​

​​}​​