How does an iOS app know about an incoming call and number that is calling while running in background?

Question

I want my iOS app to do something special when a call comes in and the app itself is running in background. I Googled and found a function named applicationWillResignActive, but it is called when an application is running and is interrupted. This interruption could be due to an incoming call or an sms or when the user quits the application. But in my case I want my app to be in the background waiting for an incoming call and I would also like the app to read the number that called and look up that number in the contacts list of the phone. As suggested by other people that there was another similar question at this link but that says that Apple would reject the App as a breach of privacy. But in my case I am not extracting the numbers who called. The number will be used only while the call is coming after call is either received or cancelled I would clear the variable storing that value. Please let me know how this can be achieved and if doing this would be fine with Apple.

Answer 1

[[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(appHasGoneInBackground) name:UIApplicationDidEnterBackgroundNotification
                                               object:nil];

Check for application enter in background....

-(void)appHasGoneInBackground
    {

        [[NSNotificationCenter defaultCenter] removeObserver:self];
        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
            t = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(updateCounter) userInfo:nil repeats:YES];
            [[NSRunLoop currentRunLoop] addTimer:t forMode:NSDefaultRunLoopMode];
            [[NSRunLoop currentRunLoop] run];
        });
    }



    -(void)updateCounter
    { [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(call) name:AVAudioSessionInterruptionNotification object:nil];

    }