JS工厂模式开发实践案例分析

define(function(){
 var self = null,
 start = null,
 move = null,
 end = null,
 handle = null,
 timer = null,
 left = 0,
 x = 0,
 startX = 0,
 baseWidth = window.screen.width, // 移动设备屏幕的宽度
 baseSize = baseWidth * 0.2,   // 滑动切换阈值
 banner = document.getElementById("banner"), // 获取Banner
 center = document.getElementById("center"), // 获取center
 ulList = document.getElementsByTagName("ul"),
 incBanner = document.getElementById('incBanner'),
 incCenter = document.getElementById('incCenter');
 var app = {
  init : function(){
   self = this;
   start = self.touchStart;
   move = self.touchMove;
   end = self.touchEnd;
   handle = self.addHandler;
   self.pageInit();
   self.bindTouch(banner, start, move, end);
   self.bindTouch(center, start, move, end);
   self.shiftBanner(banner);
  },
  pageInit : function(){
   for (var i=0; i < ulList.length; i++) {
    ulList[i].style.left = 0 + 'px';
    ulList[i].style.width = 3 * baseWidth + 'px';
   }
  },
  bindTouch : function(elem, handler1, handler2, handler3){
   handle(elem, "touchstart", handler1);
   handle(elem, "touchmove", handler2);
   handle(elem, "touchend", handler3);
  },
  touchStart : function(event){
   var touch = event.touches[0];
   left = parseInt(this.style.left);
   x = 0;
   startX = 0;
   startX = touch.pageX;  //刚触摸时的坐标
   if(this == banner){
    timer = clearInterval(timer);
   }
  },
  touchMove : function(event){ //滑动过程
   var touch = event.touches[0];    
   x = startX - touch.pageX;  //滑动的距离 
   this.style.left = left - x + 'px';   
  },
  touchEnd : function(event){    //手指离开屏幕
   self.move(this);
   self.moveAdjust(this);
   self.indicate(this);
   if(this == banner){
    self.shiftBanner(banner);
   }
  },
  move : function(elem){
   var leftTmp = left;   //缓存touchMove结束时的滑动位置
   elem.style.left = left;
   if (x > baseSize) {
    elem.style.left = left - baseWidth + 'px';
   } else if (x < -baseSize) {
    elem.style.left = left + baseWidth + 'px';
   } else {
    elem.style.left = leftTmp + 'px';
   }
  },
  moveAdjust : function(elem){
   left = parseInt(elem.style.left)
   if (left < -baseWidth * 2) {
    left = -baseWidth * 2;
    elem.style.left = left + 'px';
   }
   if (left > 0) {
    left = 0;
    elem.style.left = left + 'px';
   }
   x = 0; 
  },
  indicate : function(elem){
   if (elem == banner) {
    self.activeClass(incBanner);
   }else if (elem == center) {
    self.activeClass(incCenter);
   }
  },
  activeClass : function(elem){
   var len = elem.children.length;
   for (var i = 0; i < len; i++) {
     elem.children[i].className=" ";
    }
   if (left == 0) {
    elem.children[0].className = "active";
   } else if (left == (-baseWidth)) {
    elem.children[1].className = "active";
   }else if (left == (-2*baseWidth)) {
    elem.children[2].className = "active";
   }
  },
  shiftBanner : function(elem){
   var t = new Date();
   var tmpLeft = parseInt(elem.style.left);
   timer = setInterval(function(){
    if ((tmpLeft == 0) || (tmpLeft == -baseWidth)) {
     elem.style.left = tmpLeft - baseWidth + 'px';
    } else if (tmpLeft == -2*baseWidth) {
     elem.style.left = 0 + 'px';
    }
    tmpLeft = parseInt(elem.style.left);
    left = tmpLeft;
    // console.log(elem.style.left);
    // console.log(t);
    self.indicate(banner);
   },4000);
  },
  addHandler : function(element, type, handler){
   if (element.addEventListener) {
    element.addEventListener(type, handler, true);
   } else if (element.attachEvent) {
    element.attachEvent("on" + type, handler);
   } else {
    element["on" + type] = handler;
   }
  }
 };
 return {
  init : function(){
   app.init();
  }
 };
});