【Vue】23.vue项目中子组件接收不到父组件传值的问题

项目背景：使用vue-cli3搭建的项目框架

问题描述：父组件里面有一个轮播图，这个轮播图我封装了一下，封装成了一个组件引到了这个页面里面，我们产品的需求是，根据页面获取到的婚姻状态做判断，第二张图片的链接点进去显示不同的文章，意思就是根据婚姻状态给第二张图片赋不同的链接值，所以我需要传给这个轮播图组件一个婚姻状态，这个婚姻状态呢，又是从接口里面动态获取到的，这个轮播图呢，又是在页面加载的时候就显示的。

刚开始的做法是这样的，data里面定义一个变量info.marriage，根据后台接口返回的婚姻状态，给info.marriage赋值，然后传到SlideShow这个轮播图组件里面，但是这样的话，由于接口异步加载的问题，子组件拿不到父组件传过来的数据，郁闷了好久，一直没找到原因。后来仔细看了一下vue组件的生命周期，发现了问题的所在，后来想到一种解决方法就是，在组件上加个开关，初始化的时候给一个false，数据加载赋值的时候再给他赋值为true，这样整一个加载顺序就不一样了，这样问题就解决了。

代码修改前：

  import {mapGetters, mapMutations} from 'vuex';
  import {getSingleReportResult, satisfyReport} from '../api/insurance';
  import CONSTANT from '../common/js/constant';
  import SlideShow from '../components/SlideShow.vue';

  export default {
    name: 'EvalutionDetails',
    data() {
      return {
        info: {
          marryType: '',
          marriage: '',
        },
      };
    },
    computed: {
      ...mapGetters(['getWxUnionId']),
    },
    beforeMount() {
      console.log('beforeMount');
    },
    mounted() {
      console.log('mounted');
      if (this.pageType === 2) {
        this.drawLine();
      }
    },
    beforeCreate() {
      console.log('beforeCreate');
    },
    created() {
      this.init();
      console.log('created');
    },
    methods: {
      ...mapMutations(['SAVE_WX_UNION_ID']),
      init() {
        this.reportType = this.getQueryString('reportType');
        this.resultId = this.getQueryString('resultId');
        this.serialNo = this.getQueryString('serialNo');
        this.unionId = this.getQueryString('unionId');
        this.pageType = this.getQueryString('reportType');
        this.SAVE_WX_UNION_ID(this.unionId);
        getSingleReportResult({
          reportType: this.reportType,
          resultId: this.resultId,
          serialNo: this.serialNo,
        }).then((response) => {
          if (response && response.data) {
            this.info.marryType = response.data.marriage;
            if (response.data.marriage === CONSTANT.INSURANCE_REPORT_MARRY_TYPE.SINGLE) {
              this.info.marriage = '1';
            } else if (response.data.marriage
              === CONSTANT.INSURANCE_REPORT_MARRY_TYPE.MARRIED_PREGNANCY) {
              this.info.marriage = '2';
            }
       }).catch((err) => {
          console.log(err);
        });
      },
      deductPointBackToParent(childValue) {
        console.log(`this.info.marriage: ${childValue}`);
      },
      getQueryString(name) {
        const reg = new RegExp(`(^|&)${name}=([^&]*)(&|$)`);
        const r = window.location.search.substr(1).match(reg);
        if (r != null) return unescape(r[2]);
        return null;
      },
    },
    components: {
      SlideShow,
    },
  };

子组件没有加开关以前 ，父组件加载子组件执行顺序如下：

代码修改后：

  import {mapGetters, mapMutations} from 'vuex';
  import {getSingleReportResult, satisfyReport} from '../api/insurance';
  import CONSTANT from '../common/js/constant';
  import SlideShow from '../components/SlideShow.vue';

  export default {
    name: 'EvalutionDetails',
    data() {
      return {
        info: {
          marryType: '',
          marriage: '',
        },
        testShow: false,
      };
    },
    computed: {
      ...mapGetters(['getWxUnionId']),
    },
    beforeMount() {
      console.log('beforeMount');
    },
    mounted() {
      console.log('mounted');
      if (this.pageType === 2) {
        this.drawLine();
      }
    },
    beforeCreate() {
      console.log('beforeCreate');
    },
    created() {
      this.init();
      console.log('created');
    },
    methods: {
      ...mapMutations(['SAVE_WX_UNION_ID']),
      init() {
        this.reportType = this.getQueryString('reportType');
        this.resultId = this.getQueryString('resultId');
        this.serialNo = this.getQueryString('serialNo');
        this.unionId = this.getQueryString('unionId');
        this.pageType = this.getQueryString('reportType');
        this.SAVE_WX_UNION_ID(this.unionId);
        getSingleReportResult({
          reportType: this.reportType,
          resultId: this.resultId,
          serialNo: this.serialNo,
        }).then((response) => {
          if (response && response.data) {
            this.info.marryType = response.data.marriage;
            if (response.data.marriage === CONSTANT.INSURANCE_REPORT_MARRY_TYPE.SINGLE) {
              this.testShow = true;
              this.info.marriage = '1';
            } else if (response.data.marriage
              === CONSTANT.INSURANCE_REPORT_MARRY_TYPE.MARRIED_PREGNANCY) {
              this.testShow = true;
              this.info.marriage = '2';
            } else {
              this.testShow = true;
            }
        }).catch((err) => {
          console.log(err);
        });
      },
      deductPointBackToParent(childValue) {
        console.log(`this.info.marriage: ${childValue}`);
      },
      getQueryString(name) {
        const reg = new RegExp(`(^|&)${name}=([^&]*)(&|$)`);
        const r = window.location.search.substr(1).match(reg);
        if (r != null) return unescape(r[2]);
        return null;
      },
    },
    components: {
      SlideShow,
    },
  };

子组件加了开关以后 ，父组件加载子组件执行顺序如下：