switchSlideBtn : function(){
var slideNum = this.posterItems.size(); //獲得當(dāng)前的這個(gè)carousel對(duì)象的總共的幀數(shù)
var str = ''; 
var firstBtnLeft = (this.setting.width-(slideNum-1)*15-slideNum*15)/2; //規(guī)定第一個(gè)按鈕放的位置
for(var i = 0; i<slideNum; i++){
str += '<button class="btn"></button>'; //把每一個(gè)btn的代碼添加到str字符串中，然后一次性添加到selBtn這里面，避免多次修改DOM
}
$('#selBtn').html(str); 
for(var i = 0;i<slideNum; i++){
$('#selBtn .btn').eq(i).css('left' , firstBtnLeft+i*30); 
} 
}, 

$('#selBtn .btn').each(function(){
$(this).hover(function(){
if(self.rotateFlag){
self.switchSlide(this);
}
},function(){
});
})

//用切換幻燈片的按鈕切換幻燈片的方法
switchSlide : function(btn){
var self = this;
var BtnIndex = $(btn).index(); //獲得當(dāng)前是哪一個(gè)按鈕執(zhí)行事件
$('#selBtn .btn').css('background','rgba(255,255,255,.3)');
$('#selBtn .btn').eq(BtnIndex).css('background','rgba(255,255,255,1)');
var level = Math.floor(this.posterItems.size()/2),
posterItemsLength = this.posterItems.size(),
index;
$('.poster-item').filter(function(i,item){
if($(this).css('z-index') == level){ //獲得當(dāng)前顯示的第一幀的下標(biāo)
index = i;
}
});
var nextTime = BtnIndex-index; //向左旋轉(zhuǎn)nextTime次
var arr = [],zIndexArr=[];
for(var i = 0;i < posterItemsLength;i++){ 
arr.push(i); 
}
arr = arr.concat(arr); //添加一個(gè)數(shù)組，用來(lái)模擬Li的下標(biāo)
if(nextTime > 0){ //prev 左旋轉(zhuǎn),把數(shù)組的后半部分向前移動(dòng)nextTime個(gè)下標(biāo)
self.rotateFlag = false; //注意這里吧self.rotateFlag這個(gè)標(biāo)識(shí)放在里面來(lái)修改了。
this.posterItems.each(function(i, item){
var posterItemIndex = arr.lastIndexOf(i); //獲得li節(jié)點(diǎn)在arr中對(duì)應(yīng)的下標(biāo)
var tag = $(self.posterItems[arr[posterItemIndex-nextTime]]),
width = tag.width(),
height = tag.height(),
zIndex = tag.css('zIndex'),
opacity = tag.css('opacity'),
left = tag.css('left'),
top = tag.css('top');
zIndexArr.push(zIndex);
$(item).animate({
width : width,
height : height,
opacity : opacity,
left : left,
top : top
},self.setting.speed,function(){
self.rotateFlag = true; //在每一個(gè)幀的動(dòng)畫(huà)都執(zhí)行完畢之后，self.rotateFlag改為true，才能執(zhí)行下一次動(dòng)畫(huà)
});
});
self.posterItems.each(function(i){
$(this).css('zIndex',zIndexArr[i]); //把這個(gè)z-index提出來(lái)單獨(dú)改變是為了讓z-index這個(gè)屬性的改變最先執(zhí)行，并且不需要?jiǎng)赢?huà)
});
}
if(nextTime < 0){ //next 右旋轉(zhuǎn),把數(shù)組的前半部分向后移動(dòng)nextTime的絕對(duì)值個(gè)下標(biāo)
self.rotateFlag = false;
this.posterItems.each(function(i, item){
var posterItemIndex = arr.indexOf(i), //獲得li節(jié)點(diǎn)在arr中對(duì)應(yīng)的下標(biāo)
tag = $(self.posterItems[arr[posterItemIndex+Math.abs(nextTime)]]),
width = tag.width(),
height = tag.height(),
zIndex = tag.css('zIndex'),
opacity = tag.css('opacity'),
left = tag.css('left'),
top = tag.css('top');
zIndexArr.push(zIndex);
$(item).animate({
width : width,
height : height,
opacity : opacity,
left : left,
top : top
},self.setting.speed,function(){
self.rotateFlag = true; 
});
});
self.posterItems.each(function(i){
$(this).css('zIndex',zIndexArr[i]);
});
}
},