Page({
 data: {
  carts:[],    // 購(gòu)物車(chē)列表
  hasList:false,   // 列表是否有數(shù)據(jù)
  totalPrice:0,   // 總價(jià)，初始為0
  selectAllStatus:true // 全選狀態(tài)，默認(rèn)全選
 },
 onShow() {
  this.setData({
   hasList: true,  // 既然有數(shù)據(jù)了，那設(shè)為true吧
   carts:[
   {id:1,title:'新鮮芹菜 半斤',image:'/image/s5.png',num:4,price:0.01,selected:true},
   {id:2,title:'素米 500g',image:'/image/s6.png',num:1,price:0.03,selected:true}
   ]
  });
  },
})

<view class="cart-box">
 <!-- wx:for 渲染購(gòu)物車(chē)列表 -->
 <view wx:for="{{carts}}">
 
  <!-- wx:if 是否選擇顯示不同圖標(biāo) -->
  <icon wx:if="{{item.selected}}" type="success" color="red" bindtap="selectList" data-index="{{index}}" />
  <icon wx:else type="circle" bindtap="selectList" data-index="{{index}}"/>
  
  <!-- 點(diǎn)擊商品圖片可跳轉(zhuǎn)到商品詳情 -->
  <navigator url="../details/details?id={{item.id}}">
   <image class="cart-thumb" src="{{item.image}}"></image>
  </navigator>
  
  <text>{{item.title}}</text>
  <text>￥{{item.price}}</text>
  
  <!-- 增加減少數(shù)量按鈕 -->
  <view>
   <text bindtap="minusCount" data-index="{{index}}">-</text>
   <text>{{item.num}}</text>
   <text bindtap="addCount" data-index="{{index}}">+</text>
  </view>
  
  <!-- 刪除按鈕 -->
  <text bindtap="deleteList" data-index="{{index}}"> × </text>
 </view>
</view>

<!-- 底部操作欄 -->
<view>
 <!-- wx:if 是否全選顯示不同圖標(biāo) -->
 <icon wx:if="{{selectAllStatus}}" type="success_circle" color="#fff" bindtap="selectAll"/>
 <icon wx:else type="circle" color="#fff" bindtap="selectAll"/>
 <text>全選</text>
 
 <!-- 總價(jià) -->
 <text>￥{{totalPrice}}</text>
</view>

getTotalPrice() {
 let carts = this.data.carts;     // 獲取購(gòu)物車(chē)列表
 let total = 0;
 for(let i = 0; i<carts.length; i++) {   // 循環(huán)列表得到每個(gè)數(shù)據(jù)
  if(carts[i].selected) {     // 判斷選中才會(huì)計(jì)算價(jià)格
   total += carts[i].num * carts[i].price;  // 所有價(jià)格加起來(lái)
  }
 }
 this.setData({        // 最后賦值到data中渲染到頁(yè)面
  carts: carts,
  totalPrice: total.toFixed(2)
 });
}

selectList(e) {
 const index = e.currentTarget.dataset.index; // 獲取data- 傳進(jìn)來(lái)的index
 let carts = this.data.carts;     // 獲取購(gòu)物車(chē)列表
 const selected = carts[index].selected;   // 獲取當(dāng)前商品的選中狀態(tài)
 carts[index].selected = !selected;    // 改變狀態(tài)
 this.setData({
  carts: carts
 });
 this.getTotalPrice();       // 重新獲取總價(jià)
}

selectAll(e) {
 let selectAllStatus = this.data.selectAllStatus; // 是否全選狀態(tài)
 selectAllStatus = !selectAllStatus;
 let carts = this.data.carts;

 for (let i = 0; i < carts.length; i++) {
  carts[i].selected = selectAllStatus;   // 改變所有商品狀態(tài)
 }
 this.setData({
  selectAllStatus: selectAllStatus,
  carts: carts
 });
 this.getTotalPrice();        // 重新獲取總價(jià)
}

// 增加數(shù)量
addCount(e) {
 const index = e.currentTarget.dataset.index;
 let carts = this.data.carts;
 let num = carts[index].num;
 num = num + 1;
 carts[index].num = num;
 this.setData({
  carts: carts
 });
 this.getTotalPrice();
},
// 減少數(shù)量
minusCount(e) {
 const index = e.currentTarget.dataset.index;
 let carts = this.data.carts;
 let num = carts[index].num;
 if(num <= 1){
  return false;
 }
 num = num - 1;
 carts[index].num = num;
 this.setData({
  carts: carts
 });
 this.getTotalPrice();
}

deleteList(e) {
 const index = e.currentTarget.dataset.index;
 let carts = this.data.carts;
 carts.splice(index,1);    // 刪除購(gòu)物車(chē)列表里這個(gè)商品
 this.setData({
  carts: carts
 });
 if(!carts.length){     // 如果購(gòu)物車(chē)為空
  this.setData({
   hasList: false    // 修改標(biāo)識(shí)為false，顯示購(gòu)物車(chē)為空頁(yè)面
  });
 }else{        // 如果不為空
  this.getTotalPrice();   // 重新計(jì)算總價(jià)格
 } 
}