


jQuery simulates the original ecological App pull up to refresh and pull down to load more pages and its principles_jquery
May 16, 2016 pm 03:46 PMIn many Apps, news or display categories have pull-down refresh and pull-up loading effects. Third-party classes that achieve this effect are provided online (see MJRefresh and EGOTableViewPullRefresh for details). It is very convenient to use, but in your spare time Yu, we can think about the principle of achieving this effect. I have said before that any animation is a lie. As long as it is not a hardware problem, most effects can be made based on the system UI.
The following code is used to refresh the page through pull-down on the jQuery mobile phone, which is very similar to the special effects code for QQ Space client or WeChat pull-down to refresh the page.
Please see the renderings below:
Online preview Source code download
html code:
<div id="wrapper"> <ul> <li>row </li> <li>row </li> <li>row </li> <li>row </li> <li>row </li> <li>row </li> <li>row </li> <li>row </li> <li>row </li> <li>row </li> </ul> </div> <script> for (var i = ; i < document.querySelectorAll("#wrapper ul li").length; i++) { document.querySelectorAll("#wrapper ul li")[i].colorfulBg(); } refresher.init({ id: "wrapper",//<------------------------------------------------------------------------------------┐ pullDownAction: Refresh, pullUpAction: Load }); var generatedCount = ; function Refresh() { setTimeout(function () { // <-- Simulate network congestion, remove setTimeout from production! var el, li, i; el = document.querySelector("#wrapper ul"); el.innerHTML = ''; for (i = ; i < ; i++) { li = document.createElement('li'); li.appendChild(document.createTextNode('async row ' + (++generatedCount))); el.insertBefore(li, el.childNodes[]); } wrapper.refresh();/****remember to refresh after action completed! ---yourId.refresh(); ----| ****/ for (var i = ; i < document.querySelectorAll("#wrapper ul li").length; i++) { document.querySelectorAll("#wrapper ul li")[i].colorfulBg(); } }, ); } function Load() { setTimeout(function () {// <-- Simulate network congestion, remove setTimeout from production! var el, li, i; el = document.querySelector("#wrapper ul"); for (i = ; i < ; i++) { li = document.createElement('li'); li.appendChild(document.createTextNode('async row ' + (++generatedCount))); el.appendChild(li, el.childNodes[]); } wrapper.refresh();/****remember to refresh after action completed?。?! ---id.refresh(); --- ****/ for (var i = ; i < document.querySelectorAll("#wrapper ul li").length; i++) { document.querySelectorAll("#wrapper ul li")[i].colorfulBg(); } }, ); } </script>
More details on the principles of pull-down refresh and pull-up loading, and the specific introduction is through code analysis.
The code is as follows:
// 下拉刷新的原理 - (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView { if (scrollView.contentOffset.y < - 100) { [UIView animateWithDuration:1.0 animations:^{ // frame發(fā)生偏移,距離頂部150的距離(可自行設(shè)定) self.tableView.contentInset = UIEdgeInsetsMake(150.0f, 0.0f, 0.0f, 0.0f); } completion:^(BOOL finished) { /** * 發(fā)起網(wǎng)絡(luò)請求,請求刷新數(shù)據(jù) */ }]; } } // 上拉加載的原理 - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate { NSLog(@"%f",scrollView.contentOffset.y); NSLog(@"%f",scrollView.frame.size.height); NSLog(@"%f",scrollView.contentSize.height); /** * 關(guān)鍵--> * scrollView一開始并不存在偏移量,但是會設(shè)定contentSize的大小,所以contentSize.height永遠(yuǎn)都會比contentOffset.y高一個(gè)手機(jī)屏幕的 * 高度;上拉加載的效果就是每次滑動(dòng)到底部時(shí),再往上拉的時(shí)候請求更多,那個(gè)時(shí)候產(chǎn)生的偏移量,就能讓contentOffset.y + 手機(jī)屏幕尺寸高大于這 * 個(gè)滾動(dòng)視圖的contentSize.height */ if (scrollView.contentOffset.y + scrollView.frame.size.height >= scrollView.contentSize.height) { NSLog(@"%d %s",__LINE__,__FUNCTION__); [UIView commitAnimations]; [UIView animateWithDuration:1.0 animations:^{ // frame發(fā)生的偏移量,距離底部往上提高60(可自行設(shè)定) self.tableView.contentInset = UIEdgeInsetsMake(0, 0, 60, 0); } completion:^(BOOL finished) { /** * 發(fā)起網(wǎng)絡(luò)請求,請求加載更多數(shù)據(jù) * 然后在數(shù)據(jù)請求回來的時(shí)候,將contentInset改為(0,0,0,0) */ }]; } }
The above content is the detailed explanation and principle of this article for jQuery to simulate the pull-up to refresh the original ecological App and the pull-down to load more pages. I hope it will be helpful to everyone.

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