获取到数据(对象、数组),截取一部分显示到页面中,用computed计算属性来实现截取数据然后直接输出到页面。
<div class="detailBox"><h1 class="detailHead">{{ActiveData.title}}</h1><div class="detailCon"><p><b>活动时间:</b>{{ActStart}} 至 {{ActEnd}}</p><p><b>报名时间:</b>{{SigStart}} 至 {{SigEnd}}</p></div></div>
data() {return {ActiveData:"",//活动详情所有数据}},methods:{//获取对应的数据this.ActiveData = response.data.data;}
computed:{ActStart(){console.log(this.ActiveData.activity_starttime);return this.ActiveData.activity_starttime.substring(5,11);},ActEnd(){return this.ActiveData.activity_endtime.substring(5,11);},SigStart(){return this.ActiveData.signup_starttime.substring(5,11);},SigEnd(){return this.ActiveData.signup_endtime.substring(5,11);},}
页面如愿显示出想要的效果了,但是也报错了!那是因为data里的数据是在mouted中执行函数才获取到数据,是在computed之后,所以在第一次computed计算时,data中的ActiveData数据还是空的,所以computed找不到ActiveData里的数据。就会报undefinded接着是Errorinrender: "TypeError:……"获取到值后重新计算又出现了获取到的值。
解决方法一:
给要截取的数据赋一个默认值,computed计算属性会先去计算默认值,在获取到新值后重新计算,就不会报undefinded的错误了。
data() {return {ActiveData:"",//活动详情所有数据ActStarts:"",//活动开始时间ActEnds:"",//活动结束时间SigStarts:"",//报名开始时间SigEnds:"",//报名结束时间}},methods:{//获取对应的数据this.ActiveData = response.data.data;this.ActStarts = response.data.data.activity_starttime;this.ActEnds = response.data.data.activity_endtime;this.SigStarts = response.data.data.signup_starttimethis.SigEnds = response.data.data.signup_endtime}
computed:{ActStart(){console.log(this.ActStarts);return this.ActStarts.substring(5,11);},ActEnd(){return this.ActEnds.substring(5,11);},SigStart(){return this.SigStarts.substring(5,11);},SigEnd(){return this.SigEnds.substring(5,11);},}
解决方法二:
在computed中增加if判断,在data中的ActiveData里有数据时才在computed中返回对应的数据
data() {return {ActiveData:"",//活动详情所有数据}},methods:{//获取对应的数据this.ActiveData = response.data.data;}
computed:{ActStart(){console.log(this.ActiveData.activity_starttime);if(this.ActiveData.activity_starttime !== undefined){return this.ActiveData.activity_starttime.substring(5,11);}},ActEnd(){if(this.ActiveData.activity_endtime !== undefined){return this.ActiveData.activity_endtime.substring(5,11);}},SigStart(){if(this.ActiveData.signup_starttime !== undefined){return this.ActiveData.signup_starttime.substring(5,11);}},SigEnd(){if(this.ActiveData.signup_endtime !== undefined){return this.ActiveData.signup_endtime.substring(5,11);}},}