Question

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:

1. User pulls down meeting dates
2. User navigates to another section of the app
3. 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?

Answer 1

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
    }
}