iOS NStimer in Background

[erdinc27]

hey all. i want to develop an application which works like an alarm logic. i trigger the method which calculates the time with a timer but the problem is when i take the application to background the timer doesnt work. here my code is

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    [[NSNotificationCenter defaultCenter] postNotificationName:@"BackgroundNotification" object:self];
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    [[NSNotificationCenter defaultCenter] postNotificationName:@"ForegroundNotification" object:self];
}

ViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.myTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(checkTheIftarTime) userInfo:nil repeats:YES];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(theAppInBackground) name:@"BackgroundNotification" object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(theAppIsActive) name:@"ForegroundNotification" object:nil];
}

- (void)theAppInBackground
{
    [myTimer invalidate];
    myTimer=nil;
}

- (void)theAppIsActive
{
    self.myTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(checkTheTime) userInfo:nil repeats:YES];
}

how i can keep calculating the time when the application is in background?

 

[xArtx]

By calculating the difference in system time.

 

[dejo]

how i can keep calculating the time when the application is in background?

Have you read the iOS App Programming Guide, in particular the section on "Background Execution and Multitasking"?

 

[lastcall]

hey all. i want to develop an application which works like an alarm logic. i trigger the method which calculates the time with a timer but the problem is when i take the application to background the timer doesnt work. here my code is

how i can keep calculating the time when the application is in background?

You didn't post code to the "checkTheIftarTime" method.

If you want your timer to persist, even if your app crashes or exits, then I would store the start time somewhere, preferrably in NSUserDefaults.

 

[PhoneyDeveloper]

Timers don't run in the background unless your code creates a background task (UIBackgroundTask). Background tasks only run for about ten minutes. There are a few types of apps that can get around these restrictions but apple is strict about enforcing those restrictions.

Look at local notifications or even remote notifications if you want your app to be called back at a time that is more than ten minutes in the future.

 

[MattInOz]

Maybe you need to look at getting the system to notify you when the time is up.

 

[erdinc27]

thanks for the helps. i used local notifications as phone developer suggested