我一直在通过谷歌浏览各种解释，但我仍然无法弄清楚这段代码何时触发，屏幕一片漆黑。谁能发现错误？更新-(IBAction)playVideo:(id)sender{NSURL*videoUrl=[[DataStoresingletonInstance]getVideoUrl:selfwithUuid:self.eventDetailVC.event.uuid];if([videoUrlcheckResourceIsReachableAndReturnError:nil]==NO){NSLog(@"Videodoesn'tnotexist.");return;}MPMoviePlayerC