Q:

In-app alert from list of NSDates

I pull down a list of meeting dates from a server to my app. I parse through all of them and save them as NSDates. 
It's easier to give a use case:

User pulls down meeting dates
User navigates to another section of the app
If it is 15min until a respective meeting time, display an alert in whichever view they are in. 

I have all of the above working except for a method to notify the app a time is about to start. 
I am guessing this is the perfect time for NSNotificationCenter. 
So my question is if I have an array of NSDates, how to constantly monitor if one 15 away? 

A:

Use below code to schedule a notification:
Just give firedate = (date_saved-15minutes)
   UILocalNotification *localNotif = [[UILocalNotification alloc] init];

    if (localNotif == nil)
        return FALSE;

    localNotif.fireDate = fireDate;
    localNotif.repeatInterval = repeatInterval;
    localNotif.timeZone = [NSTimeZone defaultTimeZone];

    localNotif.alertBody = @"Meeting";

    // Set the action button
    localNotif.hasAction = YES;

    localNotif.alertAction = NSLocalizedString(@"Show",nil); 

    localNotif.soundName = UILocalNotificationDefaultSoundName;

    localNotif.applicationIconBadgeNumber = 1;

    /* SCHEDULE NOTIFICATION */
    [[UIApplication sharedApplication] scheduleLocalNotification:localNotif];

Do this too declare a property localNotification in appdelegate.h and intercept notification then like below:
UILocalNotification *localNotification;
@property (nonatomic, retain) UILocalNotification *localNotification;
@synthesize localNotification;

- (void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification {

    self.localNotification = notification;
    NSLog(@"NOTIFICATION - DID RECEIVE");
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    if (self.localNotification) 
    {
         // Do whatever you want
    }
}

