vue实现购物车加减

<link rel="stylesheet" href="css/bootstrap.css" />
<script type="text/javascript" src="js/vue.js" ></script>

<div id="app">
 <div class="container">
 <table class="table table-bordered table-hover"> 
 <tr>
 <td>
  <input type="checkbox" v-model="checkAll" @click="selectAll" />
 </td>
 <td>
 商品名称
 </td>
 <td>
 商品价格
 </td>
 <td>
 商品数量
 </td>
 <td>
 商品总额
 </td>
 <td>
 操作
 </td>
 </tr>
  <tr v-for="(item,index) in listInfo">
  <td>
  <input type="checkbox" :value="item.id" v-model="checkItem" @change="selectOne" />
  </td>
 <td>{{item.shopName}}</td>
 <td>{{item.shopPrice}}</td>
 <td>
 <button class="btn btn-default" @click="reduce(index)">-</button>
 <input type="text" v-model="item.shopCount" />
 <button class="btn btn-default" @click="add(index)">+</button>
 </td>
 <td>
 {{item.shopPrice*item.shopCount}}
 </td>
 <td>
 <button class="btn btn-warning" @click="del(index)">删除</button>
 </td>
 </tr> 
 </table>
 <p class="text-right">
 金额总计:{{sum}}
 </p>
 <p class="text-right">
 商品数量:{{count}}
 </p>
 <hr />
 <form>
 <div class="form-group">
 <input class="form-control" placeholder="商品名称" v-model="shopName" />
 </div>
 <div class="form-group">
 <input class="form-control" placeholder="商品价格" v-model = "shopPrice"/>
 </div>
 <div class="form-group">
 <button class="btn btn-primary" type="button" @click="addInfo">增加</button>
 </div>
 </form>
 </div>
</div>

<script>
 new Vue({
 el:"#app",
 data:{
 listInfo:[
 {id:1,shopName:"男装1",shopPrice:1000,shopCount:0},
 {id:2,shopName:"男装2",shopPrice:2000,shopCount:0},
 {id:3,shopName:"男装3",shopPrice:3000,shopCount:0},
 {id:4,shopName:"男装4",shopPrice:4000,shopCount:0},
 {id:5,shopName:"男装5",shopPrice:5000,shopCount:0},
 ],
 shopName:"",
 shopPrice:"",
 checkItem:[],
 checkAll:false
 },
 methods:{
 add:function(index){
 this.listInfo[index].shopCount++
 
 },
 reduce:function(index){
 if(this.listInfo[index].shopCount<=0){
 this.listInfo[index].shopCount = 0
 }else {
 this.listInfo[index].shopCount--
 }
 
 },
 del:function(index){
  this.listInfo.splice(index,1)
 },
 addInfo:function(){
// alert(1)
 
 var obj = {
 id:this.listInfo.length+1,
 shopName:this.shopName,
 shopPrice:this.shopPrice,
 shopCount:0
 }
 console.log(obj)
 this.listInfo.push(obj) 
 },
 
 selectAll:function(){
 this.checkItem = []
 if(!this.checkAll){
 for (var i=0;i<this.listInfo.length;i++) {
 this.checkItem.push(this.listInfo[i].id)
 }
 }else {
 this.checkItem = []
 this.checkAll = false
 }
 },
 selectOne(){
 console.log(this.checkItem)
 if(this.checkItem.length == this.listInfo.length){
 this.checkAll = true
 }else {
 this.checkAll = false
 }
 }
 },
 computed:{
 sum(){
 var total = 0
 for (var i=0;i<this.listInfo.length;i++) {
 total+=parseFloat(this.listInfo[i].shopPrice)*parseFloat(this.listInfo[i].shopCount)
 }
 return total 
 },
 count:function(){
 var total = 0
 for (var i=0;i<this.listInfo.length;i++) {
 total+=parseInt(this.listInfo[i].shopCount)
 }
 return total
 }
 }
 })
</script>