iphone - 如何在后台播放音乐 iphone sdk

Question

我正在开发一个应用程序，我在应用程序中设置了计时器，之后我进入后台，当时间结束时，我想在后台播放音乐。但是音乐没有播放？

Answer 1

参考ios-sdk_background-audio。你会很有帮助的。祝你好运

Answer 2

使用此计时器代码设置计时器

UIBackgroundTaskIdentifier bgTask =0;
UIApplication  *app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    [app endBackgroundTask:bgTask]; 
}];

 self.secondsTimer = [NSTimer 
                         scheduledTimerWithTimeInterval:1 
                         target:self 
                         selector:@selector(timerFireMethod:) 
                         userInfo:nil 
                         repeats:NO];

火法——- (void) timerFireMethod:(NSTimer *) theTimer {}

在此火灾方法中，使用以下代码播放媒体文件-

NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"tujhbinjena" ofType:@"mp3"]];

[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

NSError *error;
audioPlayer = [[AVAudioPlayer alloc]
               initWithContentsOfURL:url
               error:&error];
audioPlayer.delegate=self;
audioPlayer.volume=1.0;
if (error)
{
    NSLog(@"Error in audioPlayer: %@", 
          [error localizedDescription]);
} else {
    audioPlayer.delegate = self;
    [audioPlayer prepareToPlay];
    [audioPlayer play]
}`  

[自己成为FirstResponder]；[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil]; [[AVAudioSession sharedInstance] setActive: YES error: nil];

- (BOOL)canBecomeFirstResponder {
    return YES;
}

在ViewDidUnload您需要执行以下几行

[[UIApplication sharedApplication] endReceivingRemoteControlEvents];
[self resignFirstResponder];

您需要按照处理AVAudioPlayerDelegate委托方法，并且要在后台播放音频，您需要在Info.plist 中添加一个参数，即“所需的背景模式”，此键的值为“应用程序播放音频”。如果有任何疑问，请告诉我。

Answer 3

对于此功能，您可以使用此方法：-

 -(void)notificationSchedue

   {

  NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];

//---------remainingTime NSUserDefaults 包含未来日期--------//

   NSString *datevalueremaining= [[NSUserDefaults   standardUserDefaults]valueForKey:@"remainingTime"];


   NSDateFormatter *dateFormat = [[[NSDateFormatter alloc] init] autorelease];
   [dateFormat setDateFormat:@"dd/MM/yyyy HH:mm:ss"];

   NSDate *dateremaining=[dateFormat dateFromString:datevalueremaining];


   NSDate *pickerDate = dateremaining;
NSDateComponents *dateComponents = [calendar components:( NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit ) 
                                               fromDate:pickerDate];
NSDateComponents *timeComponents = [calendar components:( NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit ) 
                                                fromDate:pickerDate];

// Set up the fire time
 NSDateComponents *dateComps = [[NSDateComponents alloc] init];

  [dateComps setDay:[dateComponents day]];

  [dateComps setMonth:[dateComponents month]];

  [dateComps setYear:[dateComponents year]];
  [dateComps setHour:[timeComponents hour]];

  [dateComps setMinute:[timeComponents minute]];
[dateComps setSecond:[timeComponents second]];
   NSDate *itemDate = [calendar dateFromComponents:dateComps];
   [dateComps release];

  if (localNotif)
  { 
     [[UIApplication sharedApplication] cancelLocalNotification:localNotif];
     [localNotif release];
   }
  localNotif = [[UILocalNotification alloc] init];
  if (localNotif == nil)
    return;

  localNotif.fireDate = itemDate;

  localNotif.timeZone = [NSTimeZone defaultTimeZone];


  localNotif.alertBody = @"Your Time is Over";

  localNotif.alertAction = @"View";



 NSString *stringvalue=[[NSUserDefaults standardUserDefaults]valueForKey:@"goodNight"];

//-----音乐应该小于或等于 30 秒---//

   localNotif.soundName=@"s1.mp3";

    NSDictionary *infoDict = [NSDictionary dictionaryWithObject:@"someValue" forKey:@"someKey"];

 localNotif.userInfo = infoDict;

 [[UIApplication sharedApplication] scheduleLocalNotification:localNotif];

 }