                        课程
                    
                        /前端开发
                        
                            /JavaScript
                        
                        /使用vue2.0实现购物车和地址选配功能

为什么showLength赋不了值？

var vm = new Vue ({
    el:".container",
    data:{
        addressList:[],
        showLength : 3
    },
    mounted:function () {
        this.$nextTick(function () {
            this.getAddressList();
        })
    },
    computed:{
      filterAddress : function () {
          return this.addressList.slice(0, this.showLength);
      }
    },
    methods: {
        getAddressList : function () {
            this.$http.get("data/address.json").then(res=>{
                if(res.body.status == 0){
                    this.addressList = res.body.result;
                }
            })
        },
        moreAddress:function () {
            this.showLength = this.addressList.length;
        },
        lessAddress:function () {
            this.showLength = 3;
        }
    }
});

<div class="moreAddress" @click="moreAddress">
    <span @click="moreAddress" v-if="showLength < addressList.length">更多地址<i class="fa fa-angle-down"></i></span>
    <span @click="lessAddress" v-if="showLength == addressList.length">收起地址<i class="fa fa-angle-up"></i></span>
</div>