调整App组件，router-view key自定义

@@ -2,8 +2,8 @@
   <div id="app">
     <transition
       :name="`route-view-${yoho.direction}`">
-      <keep-alive>
-        <router-view :key="$route.fullPath"></router-view>
+      <keep-alive :max="20">
+        <router-view :key="routerViewKey"></router-view>
       </keep-alive>
     </transition>
   </div>
@@ -15,7 +15,14 @@ import {mapState} from 'vuex';
 export default {
   name: 'App',
   computed: {
-    ...mapState(['yoho'])
+    ...mapState(['yoho']),
+    routerViewKey() {
+      if (this.$route.meta && this.$route.meta.routerViewKey) {
+        return this.$route.meta.routerViewKey;
+      } else {
+        return this.$route.fullPath;
+      }
+    },
   },
   mounted() {
     if (this.yoho.context.needLogin) {