Question

I want to call a function in applicationDidEnterBackground this function is defined in other controller.

I have made an object to access it but it seems that function is getting killed when called.

Here is the function it basically calculates the distance and postes a notification

 -(void)calculateDistance
{

    for (NSMutableDictionary *obj in placeName) {
        CLLocation *userLocation = [[AppHelper appDelegate] mLatestLocation];
        CLLocation *annotation1 = [[CLLocation alloc] initWithLatitude:[[obj objectForKey:@"Lat"]doubleValue] longitude:[[obj objectForKey:@"long"]doubleValue]];

        CGFloat distanceTemp = [annotation1 getDistanceFrom:userLocation];

        [obj setObject:[NSNumber numberWithFloat:distanceTemp] forKey:@"distance"];
        [annotation1 release];
    }


    if ([placeName count])
    {
        NSArray *sortedArray=[placeName sortedArrayUsingFunction:intSort context:NULL];
        self.placeName = [NSMutableArray arrayWithArray:sortedArray];
        NSMutableArray *arrayTemp = [[NSMutableArray alloc] initWithArray:placeName];


        for (int i =0; i < [placeName count]; i++) 
        {
            //                  NSArray *sortedArray=[placeName sortedArrayUsingFunction:intSort context:NULL];

            NSMutableArray *tempArray = [sortedArray objectAtIndex:i];
            //DLog(@"sortedArray%@", sortedArray);8=
            NSNumber *DistanceNum = [tempArray objectForKey:@"distance"];
            NSLog(@"distance%@:::",DistanceNum);
            NSInteger intDistance = (int)[DistanceNum floatValue];

            if(intDistance<500)
            {
                NSLog(@"ho gaya bhai");
                NSString *notifications =@"Yes";
                [[AppHelper mDataManager] setObject:notifications forKey:@"notifications"]; 

                NSLog(@"notifications:%@",notifications);
                RemindMeViewController *object = [[RemindMeViewController alloc] initWithNibName:@"RemindMeViewController" bundle:nil];
                //  RemindMeViewController *object=[[RemindMeViewController alloc]initWithNibName];

                NSLog(@"notifications set");
                [object scheduleNotification];
            }
            else
            {
                // [arrayTemp removeObjectAtIndex:i];
            }   
        }

        //after for loop is ended
        self.placeName= arrayTemp;
        DLog(@"remaining",arrayTemp);

        [arrayTemp release];
        [mTableView reloadData];    
    }       
}

Answer 1

How long is your function taking to complete? You only have 5 seconds to perform tasks in applicationDidEnterBackground: and return.

From Apple’s UIApplicationDelegate Protocol Reference:

Your implementation of this method has approximately five seconds to
perform any tasks and return. If you need additional time to perform
any final tasks, you can request additional execution time from the
system by calling beginBackgroundTaskWithExpirationHandler:. In
practice, you should return from applicationDidEnterBackground: as
quickly as possible. If the method does not return before time runs
out your application is terminated and purged from memory.

You should perform any tasks relating to adjusting your user interface
before this method exits but other tasks (such as saving state) should
be moved to a concurrent dispatch queue or secondary thread as needed.
Because it’s likely any background tasks you start in
applicationDidEnterBackground: will not run until after that method
exits, you should request additional background execution time before
starting those tasks. In other words, first call
beginBackgroundTaskWithExpirationHandler: and then run the task on a
dispatch queue or secondary thread.