Implementierung der Warenkorbfunktion im WeChat-Miniprogramm

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,        // 既然有数据了，那设为true吧
          carts:[
            {id:1,title:'新鲜芹菜 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 渲染购物车列表 -->
    <view wx:for="{{carts}}">
    
        <!-- wx:if 是否选择显示不同图标 -->
        <icon wx:if="{{item.selected}}" type="success" color="red" bindtap="selectList" data-index="{{index}}" />
        <icon wx:else type="circle" bindtap="selectList" data-index="{{index}}"/>
        
        <!-- 点击商品图片可跳转到商品详情 -->
        <navigator url="../details/details?id={{item.id}}">
            <image class="cart-thumb" src="{{item.image}}"></image>
        </navigator>
        
        <text>{{item.title}}</text>
        <text>￥{{item.price}}</text>
        
        <!-- 增加减少数量按钮 -->
        <view>
            <text bindtap="minusCount" data-index="{{index}}">-</text>
            <text>{{item.num}}</text>
            <text bindtap="addCount" data-index="{{index}}">+</text>
        </view>
        
        <!-- 删除按钮 -->
        <text bindtap="deleteList" data-index="{{index}}"> × </text>
    </view>
</view>

<!-- 底部操作栏 -->
<view>
    <!-- wx:if 是否全选显示不同图标 -->
    <icon wx:if="{{selectAllStatus}}" type="success_circle" color="#fff" bindtap="selectAll"/>
    <icon wx:else type="circle" color="#fff" bindtap="selectAll"/>
    <text>全选</text>
    
    <!-- 总价 -->
    <text>￥{{totalPrice}}</text>
</view>

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)
    });
}

<p>selectList(e) {<br>    const index = e.currentTarget.dataset.index;    // 获取data- 传进来的index<br>    let carts = this.data.carts;                    // 获取购物车列表<br>    const selected = carts[index].selected;         // 获取当前商品的选中状态<br>    carts[index].selected = !selected;              // 改变状态<br>    this.setData({<br>        carts: carts<br>    });<br>    this.getTotalPrice();                           // 重新获取总价<br>}<br></p>

<p>selectAll(e) {<br>    let selectAllStatus = this.data.selectAllStatus;    // 是否全选状态<br>    selectAllStatus = !selectAllStatus;<br>    let carts = this.data.carts;<br><br>    for (let i = 0; i < carts.length; i++) {<br>        carts[i].selected = selectAllStatus;            // 改变所有商品状态<br>    }<br>    this.setData({<br>        selectAllStatus: selectAllStatus,<br>        carts: carts<br>    });<br>    this.getTotalPrice();                               // 重新获取总价<br>}<br></p>

<p>// 增加数量<br>addCount(e) {<br>    const index = e.currentTarget.dataset.index;<br>    let carts = this.data.carts;<br>    let num = carts[index].num;<br>    num = num + 1;<br>    carts[index].num = num;<br>    this.setData({<br>      carts: carts<br>    });<br>    this.getTotalPrice();<br>},<br>// 减少数量<br>minusCount(e) {<br>    const index = e.currentTarget.dataset.index;<br>    let carts = this.data.carts;<br>    let num = carts[index].num;<br>    if(num <= 1){<br>      return false;<br>    }<br>    num = num - 1;<br>    carts[index].num = num;<br>    this.setData({<br>      carts: carts<br>    });<br>    this.getTotalPrice();<br>}<br></p>

deleteList(e) {
    const index = e.currentTarget.dataset.index;
    let carts = this.data.carts;
    carts.splice(index,1);              // 删除购物车列表里这个商品
    this.setData({
        carts: carts
    });
    if(!carts.length){                  // 如果购物车为空
        this.setData({
            hasList: false              // 修改标识为false，显示购物车为空页面
        });
    }else{                              // 如果不为空
        this.getTotalPrice();           // 重新计算总价格
    }   
}