活动：修改显示逻辑

shared/domain/activityField/activityField.ts

@@ -22,6 +22,10 @@ export abstract class ActivityBase {
         return this.todayIndex;
     }
 
+    public canShow() {
+        return this.beginTime <= Date.now() && this.endTime >= Date.now()
+    }
+
     constructor(activityData: ActivityModelType, createTime: number) {
         this.activityId = activityData.activityId;
         this.delayDay = activityData.delayDay ? activityData.delayDay : 0;