如果在子路里面没有调用activated ,
可能：vue3破坏性改版原来的<keep-alive><router-view/></keep-alive>不可使用了
改为
<router-view v-slot="{ Component }">
<keep-alive>
<component :is="Component" />
</keep-alive>
</router-view>
vue-router链接https://router.vuejs.org/zh/guide/migration/#router-view-%E3%80%81-keep-alive-%E5%92%8C-transition