父组件中vuex方法更新state，子组件不能及时更新并渲染的解决方法

场景：

我实际用到的是这样的，我父组件引用子组件related,父组件调用获取页面详情的方法，更新了state值related，子组件根据该related来渲染相关新闻内容，但是页面打开的时候总是先加载子组件，子组件在渲染的时候还没有获取到更新之后的related值，即使在子组件中watch该值的变化依然不能渲染出来子组件的相关新闻内容。

我的解决办法：

父组件像子组件传值，当父组件执行了获取页面详情的方法之后，state值related更新，然后传给子组件，子组件再进行渲染，可以正常获取到。

父组件代码：

<template>
  <div id="newsDetails">
    <mt-header title="详情">
      <router-link to="/" slot="left">
        <mt-button icon="back"></mt-button>
      </router-link>
    </mt-header>
    <div class="details clearfloat">
      <h1 class="titleFont">
        {{ title }}
      </h1>
      <div class="clearfloat sourceWrap">
        <ul class="sourceFont">
          <li v-if="(pubNews==true)">
            <span class="source">{{pubName}}</span>
          </li>
          <li>
            <span class="authorName">{{authorName}}</span>
            <span class="time">{{createAt|formatTime}}</span>
          </li>
        </ul>
        <span  v-if="(pubNews==true)" class='btnFollow' @click="follow">关注</span>
      </div>
      <div class="bodyFont clearfloat" id="bodyFont" ref="bodyFont" :class="{bodyHeight:contentStatus}">
        <div v-html="content"></div>
        <div class="editor" v-if="editorName">责任编辑：{{editorName}}</div>
      </div>
      <div class="contentToggle" @click="contentStatus=!contentStatus" v-if="contentStatus">阅读全文</div>
      <Related :related="related"></Related>

　　　　<!--重点是这里  父组件向子组件传值-->

 </div> </div> </template>

import { Toast } from 'mint-ui';
  import {mapState} from 'vuex'
  import Related from './Related.vue'
  import moment from 'moment';
  export default{
    name:"NewsDetails",
    components:{
      Related,
    },
    data(){
      return {
        id:this.$route.params.id,
        topicType:"news",
        contentStatus:false,
        curHeight:0,
        bodyHeight:5000,
        hotCommentScrollTop:0
      }
    },
    created(){
      this.id=this.$route.params.id;
      this.fetchData();
      moment.locale('zh-cn');
    },
    mounted(){
      setTimeout(()=>{
        this.contentToggle();
      },500)
    },
    watch: {
      '$route'(to,from){
        this.id=this.$route.params.id;
        this.fetchData();
      }
    },
    computed: {
      ...mapState({
        title: state => state.newsDetails.title,
        authorName: state => state.newsDetails.authorName,
        pubNews: state => state.newsDetails.pubNews,
        pubName: state => state.newsDetails.pubName,
        editorName: state => state.newsDetails.editorName,
        createAt: state => state.newsDetails.createAt,
        content: state => state.newsDetails.content,
        myFavourite: state => state.newsDetails.myFavourite,
        related: state => state.newsDetails.related,
      })
    },
    filters:{
      formatTime(time){
        return moment(time).fromNow();
      },
    },
    methods:{
      fetchData(){
        this.$store.dispatch('getDetails',this.id);
      },
      follow(){
        Toast('登录后进行关注');
        this.$router.push("/login");
      },
      contentToggle(){
        this.curHeight=this.$refs.bodyFont.offsetHeight;
        if(parseFloat(this.curHeight)>parseFloat(this.bodyHeight)){
          this.contentStatus=true;
        }else{
          this.contentStatus=false;
        }
//        this.hotCommentScrollTop=this.$refs.hotComment.height;
        console.log(this.hotCommentScrollTop);
      },
    }
  }

子组件related.vue

<template>
    <div v-if="lists.length>0">
        <div class="tagTitle"><span>相关新闻</span></div>
        <div class="listItem" v-if="(item.type=='little')" v-for="(item,index) in lists" :to="{name:'details',params:{id:item.id}}" :key="index" @click="browserDetection()">
          <div class="listImg1">
            <!--<img :src="{lazy==loaded?item.thumb[0]:lazy==loading?'../../assets/images/little_loading.png':lazy==error?'../../assets/images/little_loading.png'}" alt="" v-lazy="item.thumb[0]">-->
            <img :src="item.thumb[0]" alt="" v-lazy="item.thumb[0]">
          </div>
          <div class='titleBox1'>
            <p class="listTitle">{{item.title}}</p>
            <div class="titleInfo">
              <span class="openApp">打开唐人家</span>
              <span v-if="item.top==true" class="toTop">置顶</span>
              <!--<svg class="icon" aria-hidden="true">
                <use xlink:href="#icon-dianzan"></use>
              </svg>-->
              <span class="like">阅读 {{item.read}}</span>
              <span class="time">{{item.createAt|formatTime}}</span>
            </div>
        </div>
      </div>
    </div>
</template>
<script>
  import {mapActions, mapState, mapGetters} from 'vuex'
  import moment from 'moment'
  export default{
    data(){
      return {
        lists: [],
        id:this.$route.params.id,
      }
    },
    props:{
        related:Array   //重点是这里
    },
    created(){
      moment.locale('zh-cn');
    },
    /*computed: {
      ...mapState({
        related: state => state.newsDetails.related,
      })
    },*/
    filters:{
      formatTime(time){
        return moment(time).fromNow();
      },
    },
    methods:{
    },
    watch: {
      related (val) {
        this.lists = val;
      },
      '$route'(to,from){
        this.id=this.$route.params.id
      }
    }
  }
</script>

效果如图：