sr-iHealthwx/js/iscroll-pull-up-down-new.js

var IScrollPullUpDown = function (wrapperName,iScrollConfig,pullDownActionHandler,pullUpActionHandler) {
				var iScrollConfig,pullDownActionHandler,pullUpActionHandler,pullDownEl,pullDownOffset,pullUpEl,scrollStartPos;
				var pullThreshold=5;
				var me=this;
			
				function showPullDownElNow(className) {
					// Shows pullDownEl with a given className
					pullDownEl.style.transitionDuration='';
					pullDownEl.style.marginTop='';
					pullDownEl.className = 'pullDown '+className;
				}
				var hidePullDownEl = function (time,refresh) {
					// Hides pullDownEl
					pullDownEl.style.transitionDuration=(time>0?time+'ms':'');
					pullDownEl.style.marginTop='';
					pullDownEl.className = 'pullDown scrolledUp';
			
					// If refresh==true, refresh again after time+10 ms to update iScroll's "scroller.offsetHeight" after the pull-down-bar is really hidden...
					// Don't refresh when the user is still dragging, as this will cause the content to jump (i.e. don't refresh while dragging)
					if (refresh) setTimeout(function(){me.myScroll.refresh();},time+10);
				}
			
				function init() {
					var wrapperObj = document.querySelector('#'+wrapperName);
					var scrollerObj = wrapperObj.children[0];
			
					if (pullDownActionHandler) {
						// If a pullDownActionHandler-function is supplied, add a pull-down bar at the top and enable pull-down-to-refresh.
						// (if pullDownActionHandler==null this iScroll will have no pull-down-functionality)
						pullDownEl=document.createElement('div');
						pullDownEl.className='pullDown scrolledUp';
						pullDownEl.innerHTML='<span class="pullDownIcon"></span><span class="pullDownLabel">下拉刷新</span>';
						scrollerObj.insertBefore(pullDownEl, scrollerObj.firstChild);
						pullDownOffset = pullDownEl.offsetHeight;
					}
					if (pullUpActionHandler) {
						// If a pullUpActionHandler-function is supplied, add a pull-up bar in the bottom and enable pull-up-to-load.
						// (if pullUpActionHandler==null this iScroll will have no pull-up-functionality)
						pullUpEl=document.createElement('div');
						pullUpEl.className='pullUp';
						pullUpEl.innerHTML='<span class="pullUpIcon"></span><span class="pullUpLabel" style="margin: 3px 20%">上拉加载更多</span>';
						scrollerObj.appendChild(pullUpEl);
					}
			
					me.myScroll = new IScroll(wrapperObj,iScrollConfig);
			
					me.myScroll.on('refresh',function() {
						if ((pullDownEl)&&(pullDownEl.className.match('loading'))) {
							pullDownEl.querySelector('.pullDownLabel').innerHTML = '下拉刷新';
							if (this.y>=0) {
								// The pull-down-bar is fully visible:
								// Hide it with a simple 250ms animation
								hidePullDownEl(250,true);
			
							} else if (this.y>-pullDownOffset) {
								// The pull-down-bar is PARTLY visible:
								// Set up a shorter animation to hide it
			
								// Firt calculate a new margin-top for pullDownEl that matches the current scroll position
								pullDownEl.style.marginTop=this.y+'px';
			
								// CSS-trick to force webkit to render/update any CSS-changes immediately: Access the offsetHeight property...
								pullDownEl.offsetHeight;
			
								// Calculate the animation time (shorter, dependant on the new distance to animate) from here to completely 'scrolledUp' (hidden)
								// Needs to be done before adjusting the scroll-positon (if we want to read this.y)
								var animTime=(250*(pullDownOffset+this.y)/pullDownOffset);
			
								// Set scroll positon to top
								// (this is the same as adjusting the scroll postition to match the exact movement pullDownEl made due to the change of margin-top above, so the content will not "jump")
								this.scrollTo(0,0,0);
			
								// Hide pullDownEl with the new (shorter) animation (and reset the inline style again).
								setTimeout(function() {	// Do this in a new thread to avoid glitches in iOS webkit (will make sure the immediate margin-top change above is rendered)...
									hidePullDownEl(animTime,true);
								},0);
			
							} else {
								// The pull-down-bar is completely off screen:
								// Hide it immediately
								hidePullDownEl(0,true);
								// And adjust the scroll postition to match the exact movement pullDownEl made due to change of margin-top above, so the content will not "jump"
								this.scrollBy(0,pullDownOffset,0);
							}
						}
						if ((pullUpEl)&&(pullUpEl.className.match('loading'))) {
							pullUpEl.className = 'pullUp';
							pullUpEl.querySelector('.pullUpLabel').innerHTML = '上拉加载更多';
						}
					});
			
					me.myScroll.on('scrollStart',function() {
						scrollStartPos=this.y; // Store the scroll starting point to be able to track movement in 'scroll' below
					});
						
					me.myScroll.on('scroll',function() {
						if (pullDownEl||pullUpEl) {
							if((scrollStartPos==0)&&(this.y==0)) {
								// 'scroll' called, but scroller is not moving!
								// Probably because the content inside wrapper is small and fits the screen, so drag/scroll is disabled by iScroll
								
								// Fix this by a hack: Setting "myScroll.hasVerticalScroll=true" tricks iScroll to believe
								// that there is a vertical scrollbar, and iScroll will enable dragging/scrolling again...
								this.hasVerticalScroll=true;
								
								// Set scrollStartPos to -1000 to be able to detect this state later...
								scrollStartPos=-1000;
							} else if ((scrollStartPos==-1000) && 
								         (((!pullUpEl)&&(!pullDownEl.className.match('flip'))&&(this.y<0)) ||
												  ((!pullDownEl)&&(!pullUpEl.className.match('flip'))&&(this.y>0)))) {
								// Scroller was not moving at first (and the trick above was applied), but now it's moving in the wrong direction.
								// I.e. the user is either scrolling up while having no "pull-up-bar",
								// or scrolling down while having no "pull-down-bar" => Disable the trick again and reset values...
								this.hasVerticalScroll=false;
								scrollStartPos=0;
								this.scrollBy(0,-this.y, 0);	// Adjust scrolling position to undo this "invalid" movement
							}
						}
				
						if (pullDownEl) {
							if (this.y > pullDownOffset+pullThreshold && !pullDownEl.className.match('flip')) {
								showPullDownElNow('flip');
								this.scrollBy(0,-pullDownOffset, 0);	// Adjust scrolling position to match the change in pullDownEl's margin-top
								pullDownEl.querySelector('.pullDownLabel').innerHTML = '刷新数据中...';
							} else if (this.y < 0 && pullDownEl.className.match('flip')) { // User changes his mind...
								hidePullDownEl(0,false);
								this.scrollBy(0,pullDownOffset, 0);	// Adjust scrolling position to match the change in pullDownEl's margin-top
								pullDownEl.querySelector('.pullDownLabel').innerHTML = '下拉刷新';
							}
						}
						if (pullUpEl) {
							if (this.y < (this.maxScrollY - pullThreshold) && !pullUpEl.className.match('flip')) {
								pullUpEl.className = 'pullUp flip';
								pullUpEl.querySelector('.pullUpLabel').innerHTML = '正在加载...';
							} else if (this.y > (this.maxScrollY + pullThreshold) && pullUpEl.className.match('flip')) {
								pullUpEl.className = 'pullUp';
								pullUpEl.querySelector('.pullUpLabel').innerHTML = '上拉加载更多';
							}
						}
					});			
			
					me.myScroll.on('scrollEnd',function() {
						if ((pullDownEl)&&(pullDownEl.className.match('flip'))) {
							showPullDownElNow('loading');
							pullDownEl.querySelector('.pullDownLabel').innerHTML = '刷新数据中...';
							pullDownActionHandler(this);	// Execute custom function (ajax call?)
						}
						if ((pullUpEl)&&(pullUpEl.className.match('flip'))) {
							pullUpEl.className = 'pullUp loading';
							pullUpEl.querySelector('.pullUpLabel').innerHTML = '正在加载...';
							pullUpActionHandler(this);	// Execute custom function (ajax call?)
						}
						if (scrollStartPos=-1000) {
							// If scrollStartPos=-1000: Recalculate the true value of "hasVerticalScroll" as it may have been
							// altered in 'scroll' to enable pull-to-refresh/load when the content fits the screen...
							this.hasVerticalScroll = this.options.scrollY && this.maxScrollY < 0;
						}
					});
			
				}
				init();
				return me.myScroll;
			};