iOS Running a timer within your app is in the background

Sometimes, you need to run the timer when the application is in the background as you do this?

Simple solution is to use a function applicationDidEnterBackground, which can we found in AppDelegate.

This function starts automatically if you go by in the background.

In this function we can create UIBackgroundTaskIdentifier, which run task after time:

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    UIApplication *app = [UIApplication sharedApplication];

    //create new uiBackgroundTask
    __block UIBackgroundTaskIdentifier bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
        [app endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    }];

    //and create new timer with async call: 
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        //run function methodRunAfterBackground
        NSTimer* t = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(methodRunAfterBackground) userInfo:nil repeats:NO];
        [[NSRunLoop currentRunLoop] addTimer:t forMode:NSDefaultRunLoopMode];
        [[NSRunLoop currentRunLoop] run];
    });
}

- (void)applicationDidEnterBackground:(UIApplication *)application

{

UIApplication *app = [UIApplication sharedApplication];

//create new uiBackgroundTask

__block UIBackgroundTaskIdentifier bgTask = [app beginBackgroundTaskWithExpirationHandler:^{

[app endBackgroundTask:bgTask];

bgTask = UIBackgroundTaskInvalid;

}];

//and create new timer with async call:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

//run function methodRunAfterBackground

NSTimer* t = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(methodRunAfterBackground) userInfo:nil repeats:NO];

[[NSRunLoop currentRunLoop] addTimer:t forMode:NSDefaultRunLoopMode];

[[NSRunLoop currentRunLoop] run];

});

}

In this case the function (methodRunAfterBackground) starts 10 seconds after you switch applications in the background

Comments are closed for this page

maillot real madrid pas cher

16/08/2013

I cant wait to go through additional from you. That is really an incredible weblog.

Viruss

21/10/2013

In NSTimer i set 6o and repeat =yes ,But this will be work for only 10 minutes, after 10 min. timer is stopped,
as there any other solution for run app in background,

admin

21/10/2013

Look at this post: http://zaachi.com/2013/09/30/ios-locationmanager-location-update-in-my-own-interval-with-application-in-the-background.html
This is a solution where the task can run in the background for a long time

Applications must be set up to support the actions that run in the background. You can combine location update in interval and your method.

admin

21/10/2013

iOS does not support to run the method in background in loop pernamently. You must combine it with allowed services.

IOS Developer

03/09/2014

i used same method but after some time it will force to app shutdown and timer will stop

IOS Developer

03/09/2014

it give me “has active assertions beyond permitted time” error and force to shutdown app.

plz note repeat mode = yes

Vinod

16/03/2015

Very nice tutorial its help me lots.

uttam

12/10/2015

Hi I used the below code for making calls and sending messages but the thing is when i run on device in background messages are not going again when I open the app from back ground it working agian

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

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
NSTimer* t = [NSTimer scheduledTimerWithTimeInterval:time target:self selector:@selector(startTrackingBg) userInfo:nil repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:t forMode:NSDefaultRunLoopMode];
[[NSRunLoop currentRunLoop] run];
});

Ullash

24/12/2015

Thanks a lot, was searching for this. Subscribing you

Hussain

15/11/2016

Thanks. It was really a helpful tutorial.