How to use WeChat applet to implement shopping cart function

This article mainly introduces the implementation code example of the shopping cart in the WeChat Mini Program Practical Chapter, and introduces the functional implementation of the shopping cart in detail, which has certain reference value. Those who are interested can learn more

Hello everyone, I haven’t written for almost half a month. Now I feel a little stiff when I write. The reason why I haven’t updated is that the coder also has to go to work. In addition, I have been busy with work recently, and I haven’t been able to write articles. was recognized, so I had no motivation to create again. I really couldn’t hold on at that time and was about to give up. I would like to thank the reader Cao Ming, a Korean graduate reader, for supporting me and encouraging me. I look forward to my next update. I am very I was moved, and my combat power was restored instantly. In fact, your simple likes and comments are all giving me the greatest support. Okay, the sensationalism is over, it’s time to talk about the focus of today. The shopping cart. The interface of the shopping cart is not difficult to implement, but the difficulty is It is to deal with the logic inside. Whether it is a small program or an APP, the logic of the shopping cart is the most difficult. Now I will teach you how to implement the shopping cart. First, I will show the renderings

Shopping Cart Implementation

cart.wxml

<import src="/template/quantity/index.wxml" />
<scroll-view class="scroll" scroll-y="true">
 <view class="separate"></view>
 <view wx:for="{{carts}}">
  <view class="cart_container">
   <image class="item-select" bindtap="switchSelect" data-index="{{index}}" data-id="{{index}}" src="{{item.isSelect?&#39;../../images/cart/comment_select.png&#39;:&#39;../../images/cart/comment_normal.png&#39;}}" />

   <image class="item-image" src="{{item.pic}}"></image>

   <view class="column">
    <text class="title">{{item.name}}</text>
    <view class="row">
     <text class="sku-price">￥</text>
     <text class="sku-price">{{item.price}}</text>
     <view class="sku">
      <template is="quantity" data="{{ ...item.count, componentId: index }}" />
     </view>
    </view>

   </view>
  </view>
  <view class="separate"></view>
 </view>
</scroll-view>
<view class="bottom_total">
 <view class="bottom_line"></view>

 <view class="row">
  <image class="item-allselect" bindtap="allSelect" src="{{isAllSelect?&#39;../../images/cart/comment_select.png&#39;:&#39;../../images/cart/comment_normal.png&#39;}}" />
  <text class="small_text">全选</text>
  <text>合计:￥ </text>
  <text class="price">{{totalMoney}}</text>
  <button class="button-red" bindtap="toBuy" formType="submit">去结算</button>
 </view>
</view>

The layout is not very complicated. It is a circular list that cycles out the shopping cart items, plus a bottom control for settlement. It should be reminded that, A layer of scroll-view should be added outside the loop list, so that when there is a lot of data, it can be scrolled. If you are not familiar with scroll-view, please read the previous articles by yourself, which have explanations

cat.wxss

/* pages/cart/cart.wxss */
.cart_container {
 display: flex;
 flex-direction: row;
}
.scroll {
 margin-bottom: 120rpx;
}
.column {
 display: flex;
 flex-direction: column;
}
.row {
 display: flex;
 flex-direction: row;
 align-items: center;
}
.sku {
 margin-top: 60rpx;
 margin-left: 100rpx;
}
.sku-price {
 color: red;
 position: relative;
 margin-top: 70rpx;
}
.price {
 color: red;
 position: relative;
}
.title {
 font-size: 38rpx;
 margin-top: 40rpx;
}
.small_text {
 font-size: 28rpx;
 margin-right: 40rpx;
 margin-left: 10rpx;
}
.item-select {
 width: 40rpx;
 height: 40rpx;
 margin-top: 90rpx;
 margin-left: 20rpx;
}
.item-allselect {
 width: 40rpx;
 height: 40rpx;
 margin-left: 20rpx;
}
.item-image {
 width: 180rpx;
 height: 180rpx;
 margin: 20rpx;
}
.bottom_line {
 width: 100%;
 height: 2rpx;
 background: lightgray;
}
.bottom_total {
 position: fixed;
 display: flex;
 flex-direction: column;
 bottom: 0;
 width: 100%;
 height: 120rpx;
 line-height: 120rpx;
 background: white;
}
.button-red {
 background-color: #f44336; /* 红色 */
}
button {
 position: fixed;
 right: 0;
 color: white;
 text-align: center;
 display: inline-block;
 font-size: 30rpx;
 border-radius: 0rpx;
 width: 30%;
 height: 120rpx;
 line-height: 120rpx;
}

There is nothing to say about the wxss style. Just understand its properties and call the class. Let’s focus on cart.js. The entire logic is in it.

cart.js

// pages/cart/cart.js
var Temp = require('../../template/contract.js');
Page(Object.assign({}, Temp.Quantity, {
 data: {
  isAllSelect:false,
  totalMoney:0,
  // 商品详情介绍
  carts: [
   {
    pic: "http://mz.djmall.xmisp.cn/files/product/20161201/148058328876.jpg",
    name:"日本资生堂洗颜",
    price:200,
    isSelect:false,
    // 数据设定
    count: {
     quantity: 2,
     min: 1,
     max: 20
    },
   },
   {
    pic: 'http://mz.djmall.xmisp.cn/files/product/20161201/148058301941.jpg',
    name: "倩碧焕妍活力精华露",
    price: 340,
    isSelect: false,
    // 数据设定
    count: {
     quantity: 1,
     min: 1,
     max: 20
    },
   },
   {
    pic: 'http://mz.djmall.xmisp.cn/files/product/20161201/14805828016.jpg',
    name: "特效润肤露",
    price: 390,
    isSelect: false,
    // 数据设定
    count: {
     quantity: 3,
     min: 1,
     max: 20
    },
   },
   {
    pic: 'http://mz.djmall.xmisp.cn/files/product/20161201/148058228431.jpg',
    name: "倩碧水嫩保湿精华面霜",
    price: 490,
    isSelect: false,
    // 数据设定
    count: {
     quantity: 1,
     min: 1,
     max: 20
    },
   },
   {
    pic: 'http://mz.djmall.xmisp.cn/files/product/20161201/148057953326.jpg',
    name: "兰蔻清莹柔肤爽肤水",
    price: 289,
    isSelect: false,
    // 数据设定
    count: {
     quantity: 10,
     min: 1,
     max: 20
    },
   },
   {
    pic: "http://mz.djmall.xmisp.cn/files/product/20161201/148057921620_middle.jpg",
    name: "LANCOME兰蔻小黑瓶精华",
    price: 230,
    isSelect: false,
    // 数据设定
    count: {
     quantity: 1,
     min: 1,
     max: 20
    },
   },
  ],
 },
 
 //勾选事件处理函数 
 switchSelect: function (e) {
  // 获取item项的id，和数组的下标值 
  var Allprice = 0,i=0;
  let id = e.target.dataset.id,
 
  index = parseInt(e.target.dataset.index);
  this.data.carts[index].isSelect = !this.data.carts[index].isSelect;
  //价钱统计
  if (this.data.carts[index].isSelect) {
   this.data.totalMoney = this.data.totalMoney + this.data.carts[index].price;
  }
  else {
   this.data.totalMoney = this.data.totalMoney - this.data.carts[index].price;
  }
  //是否全选判断
  for (i = 0; i < this.data.carts.length; i++) {
   Allprice = Allprice + this.data.carts[i].price;
  }
  if (Allprice == this.data.totalMoney)
  {
   this.data.isAllSelect=true;
  }
  else 
  {
   this.data.isAllSelect = false;
  }
  this.setData({
   carts: this.data.carts,
   totalMoney: this.data.totalMoney,
   isAllSelect: this.data.isAllSelect,
  })
 },
 //全选
 allSelect: function (e) {
  //处理全选逻辑
  let i = 0;
  if (!this.data.isAllSelect)
  {
   for (i = 0; i < this.data.carts.length; i++) {
    this.data.carts[i].isSelect = true;
    this.data.totalMoney = this.data.totalMoney + this.data.carts[i].price;
   }
  }
  else
  {
   for (i = 0; i < this.data.carts.length; i++) {
    this.data.carts[i].isSelect = false;
   }
   this.data.totalMoney=0;
  }
  this.setData({
   carts: this.data.carts,
   isAllSelect: !this.data.isAllSelect,
   totalMoney: this.data.totalMoney,
  })
 },
 // 去结算
 toBuy() {
  wx.showToast({
   title: &#39;去结算&#39;,
   icon: &#39;success&#39;,
   duration: 3000
  });
  this.setData({
   showDialog: !this.data.showDialog
  });
 },
 //数量变化处理
 handleQuantityChange(e) {
  var componentId = e.componentId;
  var quantity = e.quantity;
  this.data.carts[componentId].count.quantity = quantity;
  this.setData({
   carts: this.data.carts,
  });
 }
}));

Introduce the parameters used

1. isAllSelect: Whether to select all

2. totalMoney:Total amount

3. carts: Shopping cart product data

switchSelect Logical processing required for the check button

1. Determine whether all checks are achieved. If all are checked, the Select All button at the bottom should be lit. The basis for judgment is whether the price is equal to the total price. Of course, this is only a way of judgment. Readers can also judge by the number of ticks,

2. For the checked or canceled buttons, perform addition and subtraction calculations of the total price

3. this.setData, update the data, this is the key point, every time the data is processed, Remember to update the data

allSelect Logical processing of the select all button

1. Select all to light up the check icon of each item, and then count Total price. If not selected, it will be grayed out. The total price is 0

2. this.setData update data

WeChat applet data Processing

1. Modify data method

data:{
 name:'我是初始化的name'
}

1, this.data.name

this.data.name='我是代码君data'

2, this.setData

 this.setData({
   name:'我是代码君setData'
  })

Both methods can change the data. The advantage of this.setData is that it can have a refreshing effect, that is, update the data in real time

2. Modify the object array

data:{
person:{
 name:'代码君',
 city:'厦门'
}
}

Modify all objects

this.setData({
   person:{
    name:'新代码君',
    city:'湖南'
   }
  })

Modify some data

this.setData({
   'person.name': '代码君只修改名字'
  })
//多个数组用这个
this.setData({
   'person[0].name': '代码君只修改名字'
  })

3. Add and delete data

1. Add data concat

//假设这一段是我们要新增的数组
var newarray = [{
    name:'增加的数据--'+new Date().getTime() ,
}];
//向前--用newarray与this.data.list合拼
this.data.list = newarray.concat(this.data.list);
//向后--用this.data.list与newarray合拼
this.data.list = this.data.list.concat(newarray);

2. Delete data splice() deletes data, and then returns the deleted data

//删除
 remove:function (e){
  var dataset = e.target.dataset;
  var Index = dataset.index;
  //通过index识别要删除第几条数据，第二个数据为要删除的项目数量，通常为1
  this.data.list.splice(Index,1);
  //渲染数据
  this.setData({
    list:this.data.list
  });
 }

3. Clear data

//清空
 clear:function (){
  //其实就是让数组变成一个空数组即可
   this.setData({
     list:{}
   });
 }

The above is what I compiled for everyone. I hope it will be useful to everyone in the future. help.

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