预览按钮显示bug3286

src/components/MainPage.vue

@@ -249,7 +249,12 @@ export default {
       tmpArr = this[moduleName];
       tmpNowItem = tmpArr[this.num];
       this.type = -1;
-      tmpNowItem?tmpNowItem.show = false:'';      //最后一题时没有下一题
+      if(tmpNowItem){
+        tmpNowItem.show = false;
+      }else{//最后一题时没有下一题
+        this.showPreview=false;
+      }
+
       const keyIdx = this.moduleKeys.findIndex((i)=>i==this.activeTab);
       if(this.activeTab!==this.moduleKeys[0]&&this.num===0){     //取消上一阶段的最后一题时
         this.activeTab=this.moduleKeys[keyIdx-1];