尝试使用 UILocalNotification 播放音频

Question

我的应用程序在后台状态时显示 LocalNotification。我想在 LocalNotification 被触发时播放声音。显然我可以使用 LocalNotification.Soundname 属性来提及应用程序包中的文件名。想要的是从文档目录中播放声音，因为我在应用程序处于活动状态时录制了声音并将其保存在文档目录中。我正在使用 AVAudioPlayer 对象来播放它。它在模拟器中工作正常，但在设备上不起作用。这是我的做法的代码。

if([UIApplication sharedApplication].applicationState == UIApplicationStateBackground)
                        {
                            UILocalNotification *localNotif = [[UILocalNotification alloc] init];
                            if (localNotif == nil)
                                return;
                            localNotif.fireDate = [NSDate date];
                            localNotif.timeZone = [NSTimeZone defaultTimeZone];

                            // Notification details
                            localNotif.alertBody = [NSString stringWithFormat:@"You Got %d Email(s) From %@",newMailsFrom[i],[(ModelNameEmail *)[[MailModel sharedMailModel].EmailAlertArray objectAtIndex:i] Name]];
                            // Set the action button
                            localNotif.alertAction = @"View";

                            localNotif.soundName = UILocalNotificationDefaultSoundName;
                            localNotif.applicationIconBadgeNumber = +1;

                            // Specify custom data for the notification
                            NSDictionary *infoDict = [NSDictionary dictionaryWithObject:@"someValue" forKey:@"someKey"];
                            localNotif.userInfo = infoDict;


                            //playing the sound


                            NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
                            NSString *documentsDir = [documentPaths objectAtIndex:0];

                            NSString *filename = [(ModelNameEmail *)[[MailModel sharedMailModel].EmailAlertArray objectAtIndex:0] Name];
                            NSString *filename1 = [filename stringByAppendingFormat:@".wav"];
                            NSString *filepath = [documentsDir stringByAppendingPathComponent:filename1];
                            NSLog(@"sound file path is %@",filepath);

                            //NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@/welcome.wav", [[NSBundle mainBundle] resourcePath]]];

                            NSURL *url =[NSURL fileURLWithPath:filepath];

                            NSError *error;
                            audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
                            [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];

                            audioPlayer.numberOfLoops = 0;

                            [audioPlayer play];

                            //  [[UIApplication sharedApplication] scheduleLocalNotification:localNotif];
                            [[UIApplication sharedApplication] presentLocalNotificationNow:localNotif];
                            [localNotif release];


                        `