ios 5 에서 알림 메커니즘(notification)을 사용 하여 메시지(banner 와 alert)를 표시 합 니 다.

- (void)viewWillAppear:(BOOL)animated {
    [self setupLocalNotifications];    
}

- (void)setupLocalNotifications {
    [[UIApplication sharedApplication] cancelAllLocalNotifications];
    
    UILocalNotification *localNotification = [[UILocalNotification alloc] init];
    
    // current time plus 10 secs
    NSDate *now = [NSDate date];
    NSDate *dateToFire = [now dateByAddingTimeInterval:5];
        
    NSLog(@"now time: %@", now);
    NSLog(@"fire time: %@", dateToFire);

    localNotification.fireDate = dateToFire;
    localNotification.alertBody = @"Time to get up!";
    localNotification.soundName = UILocalNotificationDefaultSoundName;
    localNotification.applicationIconBadgeNumber = 1; // increment
    
    NSDictionary *infoDict = [NSDictionary dictionaryWithObjectsAndKeys:@"Object 1", @"Key 1", @"Object 2", @"Key 2", nil];
    localNotification.userInfo = infoDict;
    
    [[UIApplication sharedApplication] scheduleLocalNotification:localNotification];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
    
    UILocalNotification *notification = [launchOptions objectForKey:UIApplicationLaunchOptionsLocalNotificationKey];
    
    if (notification) {
        [self showAlarm:notification.alertBody];
        NSLog(@"AppDelegate didFinishLaunchingWithOptions");
        application.applicationIconBadgeNumber = 0;
    }
    
    [self.window makeKeyAndVisible];
    return YES;
}

- (void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification {
    [self showAlarm:notification.alertBody];
    application.applicationIconBadgeNumber = 0;
    NSLog(@"AppDelegate didReceiveLocalNotification %@", notification.userInfo);
}

- (void)showAlarm:(NSString *)text {
	UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Alarm" 
                                                        message:text delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
	[alertView show];
}