IOS Pull-down refresh simple implementation code

Generally speaking of pull-up refresh drop-down refresh, many people may think of a third-party open source framework Egorefresh, below, how to write their own code implementation.

UITableView itself is a uiscrollview, so uitableview can implement Uiscrollview proxy method. Pull and drop-down refreshes are nothing more than a uiscrollview offset to a certain extent called the Refresh method. Implementation-(void) Scrollviewdidscroll: (uiscrollview*) ScrollView proxy method. The code is as follows:

(void)scrollViewDidScroll:(UIScrollView *)scrollView

{      // 假设偏移表格高度的20%进行刷新           if (!_isLoading) {  // 判断是否处于刷新状态，刷新中就不执行                   // 取内容的高度：          //    如果内容高度大于UITableView高度，就取TableView高度          //    如果内容高度小于UITableView高度，就取内容的实际高度          float height = scrollView.contentSize.height > _tableView.frame.size.height ?_tableView.frame.size.height : scrollView.contentSize.height;                   if ((height - scrollView.contentSize.height + scrollView.contentOffset.y) / height > 0.2) {              // 调用上拉刷新方法          }                   if (- scrollView.contentOffset.y / _tableView.frame.size.height > 0.2) {              // 调用下拉刷新方法          }      } }

IOS Pull-down refresh simple implementation code