移动端翻页插件dropload.js(支持Zepto和jQuery)
dropload.js提供了最基本的上拉翻页,下拉刷新功能。对于由服务端一次返回所有数据的情况基本通用。
但是,需求往往不是服务端一次性返回所有数据,往往还要支持服务端分页,搜索,排序,多条件筛选等功能。(比较类似美团美食的界面)
一、解决方案
改进1:由于有分页,搜索,排序,多条件筛选功能,可能都不需要上拉,进到页面就没有数据。
例如:搜索一个服务端不存在的名字。
所以,添加接口设置setHasData。
MyDropLoad.prototype.setHasData = function(ishasData) { var me = this; if (ishasData) { me.isData = true; me.$domDown.html(me.opts.domDown.domRefresh); fnRecoverContentHeight(me); } else { me.isData = false; me.$domDown.html(me.opts.domDown.domNoData); fnRecoverContentHeight(me); } };
改进2:由以上问题还引发了一个bug,选择不同的筛选条件,然后上拉加载更多,此时没有反应了。
原因较复杂,举例说明:选择不同的筛选条件,数据量不一样,如果不执行resetload,那么页面的的上拉计算距离就存在问题。
1. 只要发API到服务端,无论返回成功失败,都必须执行resetload,成功时需要在加载完全部新增的数据后resetload。
2. 更改resetload如下,添加调用计算屏幕尺寸的方法。
MyDropLoad.prototype.resetload = function() { var me = this; if (me.direction == 'down' && me.upInsertDOM) { me.$domUp.css({ 'height': '0' }).on('webkitTransitionEnd mozTransitionEnd transitionend', function() { me.loading = false; me.upInsertDOM = false; $(this).remove(); fnRecoverContentHeight(me); }); } else if (me.direction == 'up') { me.loading = false; if (me.isData) { me.$domDown.html(me.opts.domDown.domRefresh); fnRecoverContentHeight(me); } else { me.$domDown.html(me.opts.domDown.domNoData); } } }
3. 解决以上两个问题,基本解决了90%的问题,还有一个是setHasData(false)之后的处理。(假设每页的count时20条)
bug: 在筛序条件1:返回20条数据,上拉加载更多返回10条数据,此时设置setHasData(false)。选择筛选条件2,返回20条数据,上拉加载,你会惊奇的发现拉不动了。
why: setHasData(false)之后状态还停留在没有更多数据的状态。此时应该锁定了上拉加载,更改筛选条件后,没有解除锁定,所以不能上拉加载了。
解决方法:每次更改搜索条件,筛选条件,排序等时,都需要设置setHasData(true)。
二、调用方法
整体页面逻辑较复杂。这里在整体解释一遍。
1. 选择要上拉加载的DIV,添加调用方法。
注意事项:
(1)记得保存返回对象。
(2)LoadDownFn时上拉加载后的回调,这里自己要处理的逻辑。我这里时翻页发API,API参数中offset加20,然后发API。
(3)无论API返回失败成功,都必须resetload。
这里强调:
fetchData函数调用发API,失败或者成功都必须self.moreFund.resetload()。
并且失败时直接调用self.moreFund.resetload()即可。成功时要在新的数据返回后,要先用JS动态加载HTML,加载完成后在执行self.moreFund.resetload()。
self.moreFund = $('#table-fundlist').dropload({ scrollArea: window, domDown: { domClass: 'dropload-down', domRefresh: '<div class="dropload-refresh"><img class="drop-up-icon" src="images/dropload_up.png"><span>上拉加载更多</span></div>', domLoad: '<div class="dropload-load"><img class="loading-icon" src="images/droploading.gif"></div>', domNoData: '' }, loadDownFn: function() { self.apiParams.offset += 20; self.fetchData(true); } });
2. setHasData详解
(1)什么时候需要设置true。
当非翻页API触发之前。即选择新的筛选条件,选择新的搜索字段,选择新的排序字段。这个时候必须setHasData(true)。
this.moreFund.setHasData(true);
(2)什么时候设置false。
服务端返回数据后,比较服务端返回的条目数与API发送的条目数是否一致,不一致设置setHasData(false)。
if (data.length < this.apiParams.count){ this.moreFund.setHasData(false); this.moreFund.lock(); }
3. lock与unlock详解
(1)什么时候设置lock。
服务端返回数据后,比较服务端返回的条目数与API发送的条目数是否一致,不一致设置lock()。
当前页面状态不需要上拉加载时需要设置lock()。例如:在搜索框输入的状态。
(2)什么时候设置unlock。
只有一个地方需要调用。发送API之前设置unlock。
if (self.moreFund) { self.moreFund.unlock(); }
三、JS和CSS源代码
js:
(function($) { 'use strict'; var win = window; var doc = document; var $win = $(win); var $doc = $(doc); $.fn.dropload = function(options) { return new MyDropLoad(this, options); }; var MyDropLoad = function(element, options) { var me = this; me.$element = $(element); me.upInsertDOM = false; me.loading = false; me.isLockUp = false; me.isLockDown = false; me.isData = true; me._scrollTop = 0; me.init(options); }; MyDropLoad.prototype.init = function(options) { var me = this; me.opts = $.extend({}, { scrollArea: me.$element, domUp: { domClass: 'dropload-up', domRefresh: '<div class="dropload-refresh"><img class="drop-down-icon" src="../images/dropload_down.png"><span>下拉刷新</span></div>', domUpdate: '<div class="dropload-update"><img class="drop-up-icon" src="../images/dropload_up.png"><span>释放更新</span></div>', domLoad: '<div class="dropload-load"><img class="loading-icon" src="../images/droploading.gif"></div>' }, domDown: { domClass: 'dropload-down', domRefresh: '<div class="dropload-refresh"><img class="drop-up-icon" src="../images/dropload_up.png"><span>上拉加载更多</span></div>', domLoad: '<div class="dropload-load"><img class="loading-icon" src="../images/droploading.gif"></div>', domNoData: '' //domNoData : '<div class="dropload-noData"><span>暂无数据</span></div>' }, distance: 50, // 拉动距离 threshold: '', // 提前加载距离 loadUpFn: '', // 上方function loadDownFn: '' // 下方function }, options); if (me.opts.loadDownFn != '') { me.$element.append('<div class="' + me.opts.domDown.domClass + '">' + me.opts.domDown.domRefresh + '</div>'); me.$domDown = $('.' + me.opts.domDown.domClass); } if (me.opts.scrollArea == win) { me.$scrollArea = $win; me._scrollContentHeight = $doc.height(); me._scrollWindowHeight = doc.documentElement.clientHeight; } else { me.$scrollArea = me.opts.scrollArea; me._scrollContentHeight = me.$element[0].scrollHeight; me._scrollWindowHeight = me.$element.height(); } $win.on('resize', function() { if (me.opts.scrollArea == win) { me._scrollWindowHeight = win.innerHeight; } else { me._scrollWindowHeight = me.$element.height(); } }); me.$element.on('touchstart', function(e) { if (!me.loading) { fnTouches(e); fnTouchstart(e, me); } }); me.$element.on('touchmove', function(e) { if (!me.loading) { fnTouches(e, me); fnTouchmove(e, me); } }); me.$element.on('touchend', function() { if (!me.loading) { fnTouchend(me); } }); me.$scrollArea.on('scroll', function() { me._scrollTop = me.$scrollArea.scrollTop(); fnRecoverContentHeight(me) if (me.opts.threshold === '') { me._threshold = Math.floor(me.$domDown.height() * 1 / 3); } else { me._threshold = me.opts.threshold; } if (me.opts.loadDownFn != '' && !me.loading && !me.isLockDown && me._threshold != 0 && (me._scrollContentHeight - me._threshold) <= (me._scrollWindowHeight + me._scrollTop)) { fnLoadDown(); } }); function fnLoadDown() { me.direction = 'up'; me.$domDown.html(me.opts.domDown.domLoad); me.loading = true; me.opts.loadDownFn(me); } }; function fnTouches(e) { if (!e.touches) { e.touches = e.originalEvent.touches; } } function fnTouchstart(e, me) { me._startY = e.touches[0].pageY; me.touchScrollTop = me.$scrollArea.scrollTop(); } function fnTouchmove(e, me) { me._curY = e.touches[0].pageY; me._moveY = me._curY - me._startY; if (me._moveY > 0) { me.direction = 'down'; } else if (me._moveY < 0) { me.direction = 'up'; } var _absMoveY = Math.abs(me._moveY); if (me.opts.loadUpFn != '' && me.touchScrollTop <= 0 && me.direction == 'down' && !me.isLockUp) { e.preventDefault(); me.$domUp = $('.' + me.opts.domUp.domClass); if (!me.upInsertDOM) { me.$element.prepend('<div class="' + me.opts.domUp.domClass + '"></div>'); me.upInsertDOM = true; } fnTransition(me.$domUp, 0); if (_absMoveY <= me.opts.distance) { me._offsetY = _absMoveY; me.$domUp.html(me.opts.domUp.domRefresh); } else if (_absMoveY > me.opts.distance && _absMoveY <= me.opts.distance * 2) { me._offsetY = me.opts.distance + (_absMoveY - me.opts.distance) * 0.5; me.$domUp.html(me.opts.domUp.domUpdate); } else { me._offsetY = me.opts.distance + me.opts.distance * 0.5 + (_absMoveY - me.opts.distance * 2) * 0.2; } me.$domUp.css({ 'height': me._offsetY }); } } // touchend function fnTouchend(me) { var _absMoveY = Math.abs(me._moveY); if (me.opts.loadUpFn != '' && me.touchScrollTop <= 0 && me.direction == 'down' && !me.isLockUp) { fnTransition(me.$domUp, 300); if (_absMoveY > me.opts.distance) { me.$domUp.css({ 'height': me.$domUp.children().height() }); me.$domUp.html(me.opts.domUp.domLoad); me.loading = true; me.opts.loadUpFn(me); } else { me.$domUp.css({ 'height': '0' }).on('webkitTransitionEnd transitionend', function() { me.upInsertDOM = false; $(this).remove(); }); } me._moveY = 0; } } // 重新获取文档高度 function fnRecoverContentHeight(me) { if (me.opts.scrollArea == win) { me._scrollContentHeight = $doc.height(); } else { me._scrollContentHeight = me.$element[0].scrollHeight; } } MyDropLoad.prototype.lock = function(direction) { var me = this; if (direction === undefined) { if (me.direction == 'up') { me.isLockDown = true; } else if (me.direction == 'down') { me.isLockUp = true; } else { me.isLockUp = true; me.isLockDown = true; } } else if (direction == 'up') { me.isLockUp = true; } else if (direction == 'down') { me.isLockDown = true; } }; MyDropLoad.prototype.unlock = function() { var me = this; me.isLockUp = false; me.isLockDown = false; }; MyDropLoad.prototype.setHasData = function(ishasData) { var me = this; if (ishasData) { me.isData = true; me.$domDown.html(me.opts.domDown.domRefresh); fnRecoverContentHeight(me); } else { me.isData = false; me.$domDown.html(me.opts.domDown.domNoData); fnRecoverContentHeight(me); } }; MyDropLoad.prototype.resetload = function() { var me = this; if (me.direction == 'down' && me.upInsertDOM) { me.$domUp.css({ 'height': '0' }).on('webkitTransitionEnd mozTransitionEnd transitionend', function() { me.loading = false; me.upInsertDOM = false; $(this).remove(); fnRecoverContentHeight(me); }); } else if (me.direction == 'up') { me.loading = false; if (me.isData) { me.$domDown.html(me.opts.domDown.domRefresh); fnRecoverContentHeight(me); } else { me.$domDown.html(me.opts.domDown.domNoData); } } }; function fnTransition(dom, num) { dom.css({ '-webkit-transition': 'all ' + num + 'ms', 'transition': 'all ' + num + 'ms' }); } })(window.Zepto || window.jQuery);
CSS:
.dropload-up, .dropload-down { background-color: #F0EFF5; position: relative; height: 0; overflow: hidden; } .dropload-down { height: 50px; border-top: 1px solid #e5e5e5; } .dropload-refresh .drop-up-icon, .dropload-refresh .drop-down-icon, .dropload-update .drop-up-icon, .dropload-update .drop-down-icon { vertical-align: text-bottom; margin-right: 3px; height: 16px; width: 12px; } .dropload-load .loading-icon { vertical-align: middle; height: 20px; width: 20px; } .dropload-refresh span, .dropload-update span { vertical-align: middle; line-height: 18px; font-size: 16px; color: #585858; } .dropload-noData { border-bottom: 1px solid #e5e5e5; background-color: #FFFFFF; } .dropload-noData span { line-height: 18px; font-size: 14px; color: #999999; } .dropload-refresh, .dropload-update, .dropload-load, .dropload-noData { position: absolute; width: 100%; height: 50px; bottom: 0; line-height: 50px; text-align: center; } .dropload-down .dropload-refresh, .dropload-down .dropload-update, .dropload-down .dropload-load { top: 0; bottom: auto; }
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