微信小程序（11）--购物车

<view class="main">
<!-- hasList 列表是否有数据 -->
    <view wx:if="{{hasList}}">
        <view class="cart-box">
            <view class="cart-list" wx:for="{{carts}}" wx:key="{{index}}">
            <!-- 选中图标-->
                <icon wx:if="{{item.selected}}" type="success" color="red" data-index="{{index}}"  class="cart-pro-select" bindtap="selectList"/>
                <icon wx:else type="circle" class="cart-pro-select" data-index="{{index}}" bindtap="selectList"/>
                <navigator url="../details/details?id={{item.id}}"><image class="cart-thumb" src="{{item.image}}"></image></navigator>
                <text class="cart-pro-name">{{item.title}}</text>
                <text class="cart-pro-price">￥{{item.price}}</text>
                <view class="cart-count-box">
                    <text class="cart-count-down" bindtap="minusCount" data-index="{{index}}">-</text>
                    <text class="cart-count-num">{{item.num}}</text>
                    <text class="cart-count-add" bindtap="addCount" data-index="{{index}}">+</text>
                </view>
                <text class="cart-del" bindtap="deleteList" data-index="{{index}}">×</text>
            </view>
        </view>

        <view class="cart-footer">
        <!-- 全选图标 -->
            <icon wx:if="{{selectAllStatus}}" type="success_circle" color="#fff" class="total-select" bindtap="selectAll"/>
            <icon wx:else type="circle" color="#fff" class="total-select" bindtap="selectAll"/>
            <navigator url="../orders/orders"><view class="order-icon"></view></navigator>
            <text>全选</text>
            <!-- 总金额 -->
            <text class="cart-toatl-price">￥{{totalPrice}}</text>
        </view>
    </view>
    <view wx:else>
        <view class="cart-no-data">购物车是空的哦~</view>
    </view>
</view>

// page/component/new-pages/cart/cart.js
Page({
  data: {
    carts:[],               // 购物车列表
    hasList:false,          // 列表是否有数据
    totalPrice:0,           // 总价，初始为0
    selectAllStatus:true    // 全选状态，默认全选
  },
  onShow() {
    this.setData({
      hasList: true,
      carts:[
        {id:1,title:‘白菜 半斤‘,image:‘/image/s5.png‘,num:4,price:0.02,selected:true},
        {id:2,title:‘素米 500g‘,image:‘/image/s6.png‘,num:1,price:0.05,selected:true}
      ]
    });
    this.getTotalPrice();
  },
  /**
   * 当前商品选中事件
   */
  selectList(e) {
    const index = e.currentTarget.dataset.index;
    let carts = this.data.carts;
    const selected = carts[index].selected;
    carts[index].selected = !selected;
    this.setData({
      carts: carts
    });
    this.getTotalPrice();
  },

  /**
   * 删除购物车当前商品
   */
  deleteList(e) {
    const index = e.currentTarget.dataset.index;
    let carts = this.data.carts;
    carts.splice(index,1);
    this.setData({
      carts: carts
    });
    if(!carts.length){
      this.setData({
        hasList: false
      });
    }else{
      this.getTotalPrice();
    }
  },

  /**
   * 购物车全选事件
   */
  selectAll(e) {
    let selectAllStatus = this.data.selectAllStatus;
    selectAllStatus = !selectAllStatus;
    let carts = this.data.carts;

    for (let i = 0; i < carts.length; i++) {
      carts[i].selected = selectAllStatus;
    }
    this.setData({
      selectAllStatus: selectAllStatus,
      carts: carts
    });
    this.getTotalPrice();
  },

  /**
   * 绑定加数量事件
   */
  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();
  },

  /**
   * 绑定减数量事件
   */
  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();
  },

  /**
   * 计算总价
   */
  getTotalPrice() {
    let carts = this.data.carts;                  // 获取购物车列表
    let total = 0;
    for(let i = 0; i<carts.length; i++) {         // 循环列表得到每个数据
      if(carts[i].selected) {                     // 判断选中才会计算价格
        total += carts[i].num * carts[i].price;   // 所有价格加起来
      }
    }
    this.setData({                                // 最后赋值到data中渲染到页面
      carts: carts,
      totalPrice: total.toFixed(2)
    });
  }

})