我正在从我的AppDelegate类检查我的ParentEndViewController当前是否是可见类。UIStoryboard*storyboard=[UIStoryboardstoryboardWithName:@"MainStoryboard_iPhone"bundle:nil];ParentEndViewController*parent=[storyboardinstantiateViewControllerWithIdentifier:@"ParentEndViewController"];if(parent.isViewLoaded&&parent.view.wind