Example code for developing shopping cart in WeChat applet

This article mainly introduces relevant information about a simple example of the WeChat mini program shopping cart. Friends who need it can refer to

WeChat mini program. Here is a small demo that implements the shopping cart function. If you need this function Friends can refer to it.

Summary: Add or subtract product quantity, summarize price, select all or none

Design ideas:

1. Upload from the network into the following Json data format array 1. Shopping cart id: cid 2. Title title 3. Quantity num 4.PictureAddress 5. Price price 6. Subtotal 7. Whether to select selected

2. Click the checkbox toggle operation. If it is already selected, it will become unavailable after clicking. Select, on the contrary, click based on index as the identifier instead of cid, which is convenient for traversal

3. Select all operation The first click will select all, click again to not select all, select all buttonIt also follows the toggle transformation

4. Click the settlement button to take out the selected cid array for submission to the server through the network. Here is a toast as a demonstration of the result.

5. Use stepper to perform addition and subtraction operations, also use index as the identifier, and write back the num value after clicking.

6. Layout, select all and align with the bottom of the checkout button, the shopping cart mall adaptive height, similar to the weight of Android.

Steps:

Initial data rendering

1.1 Layout and style sheet

The top is a product list, and the bottom It is a select all button and an immediate settlement button

The left part of the product list is the productthumbnail, the upper right is the product title, and the lower right is the product price and quantity. The product quantity is implemented using WXStepper Addition and subtraction operations

js: Initialize a data source, which is often obtained from the network. The related interface can be found at: http://www.php.cn/

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},
    ]
  }
})

Layout file

##

<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>

Style sheet

/*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;
}

1.2 Integrate WXStepper

1.2.1 Copy component content

[2016-10-16]

Copy the contents of stepper.

wxss to cart.wxss

Copy the contents of stepper.wxml to cart.wxml

Different from the previous single component What's important is that the array minusStatus needs to be defined here to correspond to each plus and minus button. Of course, there is no problem in merging it into carts.

minusStatuses: ['disabled', 'disabled', 'normal', 'normal', 'disabled']

Original

staticCharacter WXStepper replacement Into the following code

 <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>

js code bindMinus and bindPlus are transformed into the following respectively:

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
    });
  },

The effect is as shown:

[2016-10-17]

Fix the number of manual changes saved to the array

1.3 Integrate LXCheckboxGroup

Copy the layout file code to wxml. Here you need to determine the selected status. Generally, the shopping cart check status is recorded on the network.

index value is used to

pass valuejs for traversal.

     

 <!-- 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}}"/>

The checkbox is centered

##

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

Bind click checkbox

Event

, perform an inverse selection operation on the selected state.

  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
    });
  }

Rendering:

1.4 Add Select All and Settlement Now buttons

1.4. 1 Modify the layout file to align the bottom of the above buttons, using flex and fixed height.

Reduce it to 3 lines to see if it is still at the bottom; in addition, make sure it is suspended at the bottom and will not be scrolled by the scrolling of the list items.

 <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>

之前用立即结算来实现，发现无论如何都不能实现全选部件与结算按钮分散对齐，不响应如下样式

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

样式表

/*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;
}

1.4.2 全选与全不选事件

实现bindSelectAll事件，改变全选状态

首先定义一个data值，以记录全选状态

selectedAllStatus: false

事件实现：

 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
    });
  }

1.4.3 立即结算显示目前所选的cid，以供提交到网络，商品数量应该是包括在cid中的，后端设计应该只关注cid与uid

布局文件也埋一下toast，js只要改变toast的显示与否即可。

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

为立即结算绑定事件bindCheckout，弹出cid弹窗

 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
    });
  }

1.5 底部悬浮固定

1.5.1 商品列表 .carts-list 加入 margin-bottom: 80rpx; 以及修改上边距为零，使得底部部件与分隔不重复出现，padding: 0 40rpx;

1.5.2 底部按钮 .carts-footer 加入 background: white;

1.5.3 .carts-footer 加入

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

1.6 汇总

1.6.1 首先定义一个数据源，并在布局文件中埋坑

total: ''

{{total}}

1.6.2 通用汇总函数

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
    });
  }

然后分别在bindMinus bindPlus bindCheckbox bindSelectAll onLoad中调用this.sum()

如图：

感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！

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