I know Push Notifications is all the rage lately, but let’s not forget about Local Notifications. They are much easier to implement and can sometimes be just as effective in getting Users to come back to your app. The short tutorial below will describe the steps needed to setup Local Notifications in your app.

Setup your Local Notification

-(void) setLocalNotification {
    
    NSDateComponents *comps = [[NSDateComponents alloc] init];
    [comps setYear:2013];
    [comps setMonth:05];
    [comps setDay:01];
    [comps setHour:12];
    [comps setMinute:0];
    [comps setTimeZone:[NSTimeZone systemTimeZone]];
    NSCalendar *cal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDate *setTime = [cal dateFromComponents:comps];
    
    UILocalNotification *localNotif = [[UILocalNotification alloc] init];
    if (localNotif == nil)
        return;
    localNotif.fireDate = setTime;
    localNotif.timeZone = [NSTimeZone defaultTimeZone];
	
    // Notification details
    localNotif.alertBody = @"Don't forget to come back to the app name today for your bonus!";
    // Set the action button
    localNotif.alertAction = @"View";
	
    localNotif.soundName = UILocalNotificationDefaultSoundName;
    localNotif.applicationIconBadgeNumber = 1;
	
    // Schedule the notification
    [[UIApplication sharedApplication] scheduleLocalNotification:localNotif];
}

To customize the code above change the NSDate entry to the date and time you would like your notification to fire. This method could easily be modified to take an NSDate parameter to allow you to call this method based on a dynamic date and time. Next you’ll want to change the alertBody to the message you want the user to see. It should contain a call to action so the user will be compelled to tap it to return to your app. SoundName can be changed to to accept an mp3 or wav if you wish. The example above uses the default sound setup on the users device. The application icon red badge bubble is then set to one to notify the user that their is a notification for you app that has not yet been tapped by them.

Cancelling All Notifications

    // Cancel all Notifications
    UIApplication* app = [UIApplication sharedApplication];
    NSArray *notifications = [app scheduledLocalNotifications];
    if ([notifications count] > 0)
       [app presentLocalNotificationNow:notifications[0]];

Receiving the Notification

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    
    self.mainVC = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];
    self.window.rootViewController = self.mainVC;
    [self.window makeKeyAndVisible];
    
    // Reset the Icon Alert Number back to Zero
    application.applicationIconBadgeNumber = 0;
    
    // Detect the Notification after a user taps it
    UILocalNotification *localNotif =
    [launchOptions objectForKey:UIApplicationLaunchOptionsLocalNotificationKey];
    if (localNotif) 
    {
	NSLog(@"Recieved Notification %@",localNotif);
    }
    
    return YES;
}

- (void)application:(UIApplication *)app didReceiveLocalNotification:(UILocalNotification *)notif {
	// Handle the notification when the app is running
	NSLog(@"Recieved Notification %@",notif);
}

If you would need to programmatically set an event in the users Calendar you’ll need to leverage the EventKit framework API. The EventKit framework provides classes for accessing and manipulating calendar events and reminders.

First, access your target settings, click on “Summary”, scroll down to the “Linked Frameworks and Libraries” group and click the + button to add a new framework to your project. Search for ‘EventKit.Framework’.

Then you will be able to add a method like the one below to your class.

First add the EventKit framework to the top of your *.m file.

#import 

Next use the method below to set the iCal event.

-(void) setiCalEvent {

   // Set the Date and Time for the Event
    NSDateComponents *comps = [[NSDateComponents alloc] init];
    [comps setYear:2013];
    [comps setMonth:3];
    [comps setDay:5];
    [comps setHour:9];
    [comps setMinute:0];
    [comps setTimeZone:[NSTimeZone systemTimeZone]];
    NSCalendar *cal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDate *eventDateAndTime = [cal dateFromComponents:comps];

    // Set iCal Event
    EKEventStore *eventStore = [[EKEventStore alloc] init];

    EKEvent *event = [EKEvent eventWithEventStore:eventStore];
    event.title = @"EVENT TITLE";

    event.startDate = eventDateAndTime;
    event.endDate = [[NSDate alloc] initWithTimeInterval:600 sinceDate:event.startDate];

    // Check if App has Permission to Post to the Calendar
    [eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) {
        if (granted){
            //---- code here when user allows your app to access their calendar.
            [event setCalendar:[eventStore defaultCalendarForNewEvents]];
            NSError *err;
            [eventStore saveEvent:event span:EKSpanThisEvent error:&err];
        }else
        {
            //----- code here when user does NOT allow your app to access their calendar.
            [event setCalendar:[eventStore defaultCalendarForNewEvents]];
            NSError *err;
            [eventStore saveEvent:event span:EKSpanThisEvent error:&err];
        }
    }];
}

To customize it for your app, set the date and time of the iCal event, then change the event.title to what you want the user to see in their calendar, and finally the length of the event in seconds (i.e. 600 secs = 1 hour).

    [eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) {
        if (granted){
            //---- code here when user allows your app to access their calendar.

        }else
        {
            //----- code here when user does NOT allow your app to access their calendar.

        }
    }];

On iOS6, Apple introduced a new privacy control. The user can control permissions for the contact and calender by each app. So in the code side, you need to add some way to request the permission. In iOS5 or before, you can always call it without the user having to give permission.