ios nstimer run in background for check alarm time is equal to current time and play audio

Question

I googled it for hours, but could not find any information if there is any way to keep a running NSTimer active when the app is running in the background ? Please Help me , when app is go to background then one function run and each sec check alarm time is equal to current time , then play audio and open close alarm page If anybody know alarm app open source and its run on background please share with me Here i try this , but this is not working

- (void)applicationDidEnterBackground:(UIApplication *)application
{

    inBackground=YES;
    UIApplication*    app = [UIApplication sharedApplication];

    bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
        [app endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    }];

    // Start the long-running task and return immediately.
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        while (inBackground == YES) {


            [NSTimer scheduledTimerWithTimeInterval:1.0 target:self
                                          selector:@selector(checkAlert) userInfo:nil repeats:YES];

        }


        [app endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    });

}
-(void)checkAlert
{
    NSLog(@"Chalaaaaaa");
    NSString *checkAlarmOnOff = [defaults stringForKey:@"setAlarm"];
    // Switch Alarm From Setting page
    NSString *SwitchAlarm=[defaults stringForKey:@"setSwitchAlarm"];

    if([SwitchAlarm isEqualToString:@"ON"])
    {
        if([checkAlarmOnOff isEqualToString:@"YES"])
        {
            if(![alarmRun isEqualToString:@"Yes"])
            {

                NSString *getAlarmTime = [defaults stringForKey:@"setAlarmTime"];
                 NSLog(@"AA-%@",getAlarmTime);
                 NSLog(@"BB-%@",globalClockTime);
                if([getAlarmTime isEqualToString:globalClockTime])
                {
                    [self MusicAction];

                    [_audioPlayer play];
                    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Alarm" message:@"Alarm On" delegate:self cancelButtonTitle:@"Off" otherButtonTitles:nil, nil];
                    [alert show];
                    alarmRun=@"Yes";

                }
            }

        }
    }


}

Please help me,

Answer 1

Scheduling local notification will do that you want.Use Calendar and date components for firing local notification on today at specific time or on some other date at specific time here you go

NSCalendar *calendar = [NSCalendar currentCalendar];

    // Split the date into components but only take the year, month and day and leave the rest behind
    NSDateComponents *dateComponents = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit) fromDate:[NSDate date]]; // Current Date

    // Build the date formatter
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"h:mm a"];
    // Convert the string time into an NSDate
    NSDate *time = [formatter dateFromString:@"1:59 PM"]; //your hour:minutes am/pm values

    // Split this one in components as well but take the time part this time
    NSDateComponents *timeComponents = [[NSCalendar currentCalendar] components:(NSHourCalendarUnit | NSMinuteCalendarUnit ) fromDate:time];

    // Do some merging between the two date components
    dateComponents.hour = timeComponents.hour;
    dateComponents.minute = timeComponents.minute;

    // Extract the NSDate object again
    NSDate *fireTime = [calendar dateFromComponents:dateComponents];

    NSLog(@"Fire Time is  FireTime %@", fireTime);
     localNotification.fireDate = fireTime;

if you check it in simulator then it will print TimeZone free Date/time value. Don't worry the notification will be fired with local timezone of device.