iview 下拉刷新loadTop报错解决

<div class="noData" v-if="lifeList.length==0">
<img src="../assets/images/noData.png" alt="">
<p>这里暂时尚未内容哦~亲</p>
</div>
<mt-loadmore :top-method="loadTop" ref="loadTop" v-else>
<div v-infinite-scroll="loadMore" infinite-scroll-disabled="loading" infinite-scroll-distance="10">
<LifeListItem :lists="lifeList" merchantType="user"></LifeListItem>
<div class="loading-text" v-show="{loadingTextBtn:true}">
<span v-text="loadingText"></span>
<mt-spinner v-if="(loadingComplete==false)" type="snake" :size="16"></mt-spinner>
</div>
</div>
<div class="refreshComplete" v-if="refreshComplete==true">帖子已更新</div>
</mt-loadmore>

因为我设定的页面默认进入的时候加载一次刷新函数，刚开始刷新完以后lifeList还不能及时更新过来，且我给该组件上加了v-else等判断，因此会报错：

Error in mounted hook: "TypeError: Cannot read property 'onTopLoaded' of undefined"

获取当前this.$refs能够看到有这个dom元素 loadTop
可是this.$refs.loadTop打印则为undefined

解决办法：

loadTop(){
        this.$store.dispatch('refreshLifeList', {
          city: this.city,
          country: this.country,
          category: this.category,
          page: 0,
          size: this.size
        });
        this.page++;
        if(this.lifeList.length>0){ //这个判断是新加的
          this.$refs.loadTop.onTopLoaded();
        }
        this.refreshComplete = true;
        setTimeout(() => {
          this.refreshComplete = false;
        }, 2000)
      },

给loadTop函数里的

this.$refs.loadTop.onTopLoaded(); 作一个判断便可。或者在html中不要加v-if和v-else是否展现的判断均可。