Simple example of shopping cart in WeChat mini program

Page({
  data:{
    carts: [
      {cid:1008,title:'Zippo打火机',image:'https://img12.360buyimg.com/n7/jfs/t2584/348/1423193442/572601/ae464607/573d5eb3N45589898.jpg',num:'1',price:'198.0',sum:'198.0',selected:true},
      {cid:1012,title:'iPhone7 Plus',image:'https://img13.360buyimg.com/n7/jfs/t3235/100/1618018440/139400/44fd706e/57d11c33N5cd57490.jpg',num:'1',price:'7188.0',sum:'7188.0',selected:true},
      {cid:1031,title:'得力订书机',image:'https://img10.360buyimg.com/n7/jfs/t2005/172/380624319/93846/b51b5345/5604bc5eN956aa615.jpg',num:'3',price:'15.0',sum:'45.0',selected:false},
      {cid:1054,title:'康师傅妙芙蛋糕',image:'https://img14.360buyimg.com/n7/jfs/t2614/323/914471624/300618/d60b89b6/572af106Nea021684.jpg',num:'2',price:'15.2',sum:'30.4',selected:false},
      {cid:1063,title:'英雄钢笔',image:'https://img10.360buyimg.com/n7/jfs/t1636/60/1264801432/53355/bb6a3fd1/55c180ddNbe50ad4a.jpg',num:'1',price:'122.0',sum:'122.0',selected:true},
    ]
  }
})

<view class="container carts-list">
  <view wx:for="{{carts}}" class="carts-item" data-title="{{item.title}}" data-url="{{item.url}}" bindtap="bindViewTap">
    <view>
     <image class="carts-image" src="{{item.image}}" mode="aspectFill"/>
    </view>
   <view class="carts-text">
    <text class="carts-title">{{item.title}}</text>
    <view class="carts-subtitle">
     <text class="carts-price">{{item.sum}}</text>
     <text>WXStepper</text>
    </view>
   </view>
  </view>
</view>

/*外部容器*/
.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  box-sizing: border-box;
} 

/*整体列表*/
.carts-list {
  display: flex;
  flex-direction: column;
  padding: 20rpx 40rpx;
}

/*每行单元格*/
.carts-item {
  display: flex;
  flex-direction: row;
  height:150rpx;
  /*width属性解决标题文字太短而缩略图偏移*/
  width:100%;
  border-bottom: 1px solid #eee;
  padding: 30rpx 0;
}

/*左部图片*/
.carts-image {
  width:150rpx;
  height:150rpx;
}


/*右部描述*/
.carts-text {
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

/*右上部分标题*/
.carts-title {
  margin: 10rpx;
  font-size: 30rpx;
}

/*右下部分价格与数量*/
.carts-subtitle {
  font-size: 25rpx;
  color:darkgray;
  padding: 0 20rpx;
  display: flex;
  flex-direction: row;
  justify-content:space-between;
}

/*价格*/
.carts-price {
  color: #f60;
}

 <view class="stepper">
        <!-- 减号 -->
        <text class="{{minusStatuses[index]}}" data-index="{{index}}" bindtap="bindMinus">-</text>
        <!-- 数值 -->
        <input type="number" bindchange="bindManual" value="{{item.num}}" />
        <!-- 加号 -->
        <text class="normal" data-index="{{index}}" bindtap="bindPlus">+</text>
       </view>

bindMinus: function(e) {
    var index = parseInt(e.currentTarget.dataset.index);
    var num = this.data.carts[index].num;
    // 如果只有1件了，就不允许再减了
    if (num > 1) {
      num --;
    }
    // 只有大于一件的时候，才能normal状态，否则disable状态
    var minusStatus = num <= 1 ? &#39;disabled&#39; : &#39;normal&#39;;
    // 购物车数据
    var carts = this.data.carts;
    carts[index].num = num;
    // 按钮可用状态
    var minusStatuses = this.data.minusStatuses;
    minusStatuses[index] = minusStatus;
    // 将数值与状态写回
    this.setData({
      carts: carts,
      minusStatuses: minusStatuses
    });
  },
  bindPlus: function(e) {
    var index = parseInt(e.currentTarget.dataset.index);
    var num = this.data.carts[index].num;
    // 自增
    num ++;
    // 只有大于一件的时候，才能normal状态，否则disable状态
    var minusStatus = num <= 1 ? &#39;disabled&#39; : &#39;normal&#39;;
    // 购物车数据
    var carts = this.data.carts;
    carts[index].num = num;
    // 按钮可用状态
    var minusStatuses = this.data.minusStatuses;
    minusStatuses[index] = minusStatus;
    // 将数值与状态写回
    this.setData({
      carts: carts,
      minusStatuses: minusStatuses
    });
  },

 <!-- 复选框图标 -->
    <icon wx:if="{{item.selected}}" type="success_circle" size="20" bindtap="bindCheckbox" data-index="{{index}}"/>
    <icon wx:else type="circle" size="20" bindtap="bindCheckbox" data-index="{{index}}"/>

/*复选框样式*/
.carts-list icon {
  margin-top: 60rpx;
  margin-right: 20rpx;
}

  bindCheckbox: function(e) {
    /*绑定点击事件，将checkbox样式改变为选中与非选中*/
    //拿到下标值，以在carts作遍历指示用
    var index = parseInt(e.currentTarget.dataset.index);
    //原始的icon状态
    var selected = this.data.carts[index].selected;
    var carts = this.data.carts;
    // 对勾选状态取反
    carts[index].selected = !selected;
    // 写回经点击修改后的数组
    this.setData({
      carts: carts
    });
  }

 <view class="carts-footer">
    <view bindtap="bindSelectAll">
      <icon wx:if="{{selectedAllStatus}}" type="success_circle" size="20"/>
      <icon wx:else type="circle" size="20" />
      <text>全选</text>
    </view>
    <view class="button">立即结算</view>
  </view>

  display: flex;
  flex-direction: row;
  justify-content: space-between;

/*底部按钮*/
.carts-footer {
  width: 100%;
  height: 80rpx;
  display: flex;
  flex-direction: row;
  justify-content: space-between;
}

/*复选框*/
.carts-footer icon {
  margin-left: 20rpx;
}

/*全选字样*/
.carts-footer text {
  font-size: 30rpx;
  margin-left: 8rpx;
  line-height: 10rpx;
}

/*立即结算按钮*/
.carts-footer .button {
  line-height: 80rpx;
  text-align: center;
  width:220rpx;
  height: 80rpx;
  background-color: #f60;
  color: white;
  font-size: 36rpx;
  border-radius: 0;
  border: 0;
}

 bindSelectAll: function() {
    // 环境中目前已选状态
    var selectedAllStatus = this.data.selectedAllStatus;
    // 取反操作
    selectedAllStatus = !selectedAllStatus;
    // 购物车数据，关键是处理selected值
    var carts = this.data.carts;
    // 遍历
    for (var i = 0; i < carts.length; i++) {
      carts[i].selected = selectedAllStatus;
    }
    this.setData({
      selectedAllStatus: selectedAllStatus,
      carts: carts
    });
  }

<toast hidden="{{toastHidden}}" bindchange="bindToastChange">
  {{toastStr}}
</toast>

 bindCheckout: function() {
    // 初始化toastStr字符串
    var toastStr = 'cid:';
    // 遍历取出已勾选的cid
    for (var i = 0; i < this.data.carts.length; i++) {
      if (this.data.carts[i].selected) {
        toastStr += this.data.carts[i].cid;
        toastStr += &#39; &#39;;
      }
    }
    //存回data
    this.setData({
      toastHidden: false,
      toastStr: toastStr
    });
  },
  bindToastChange: function() {
    this.setData({
      toastHidden: true
    });
  }

  position: fixed;
  bottom: 0;
  border-top: 1px solid #eee;

sum: function() {
    var carts = this.data.carts;
    // 计算总金额
    var total = 0;
    for (var i = 0; i < carts.length; i++) {
      if (carts[i].selected) {
        total += carts[i].num * carts[i].price;
      }
    }
    // 写回经点击修改后的数组
    this.setData({
      carts: carts,
      total: &#39;￥&#39; + total
    });
  }