Friday, February 10, 2017
How to Create A Local Notifications Using Objective - C
1) When the app is closed, schedule a local notification that will fire in 24 hours
- (void)applicationDidEnterBackground:(UIApplication *)application
{
UILocalNotification *notification = [[UILocalNotification alloc] init];
notification.fireDate = [[NSDate date] dateByAddingTimeInterval:60*60*24];
notification.alertBody = @"24 hours passed since last visit :(";
[[UIApplication sharedApplication] scheduleLocalNotification:notification];
}
2) if the app is opened (before the local notification fires), cancel the local notification
- (void)applicationDidBecomeActive:(UIApplication *)application
{
[[UIApplication sharedApplication] cancelAllLocalNotifications];
}
//For local Notification
first thing we need to do is register the notifications.
// New for iOS 8 - Register the notifications
UIUserNotificationType types = UIUserNotificationTypeBadge | UIUserNotificationTypeSound | UIUserNotificationTypeAlert;
UIUserNotificationSettings *mySettings = [UIUserNotificationSettings settingsForTypes:types categories:nil];
[[UIApplication sharedApplication] registerUserNotificationSettings:mySettings];
Now let’s create the notification itself
UILocalNotification *notification = [[UILocalNotification alloc] init];
if (notification)
{
notification.fireDate = _datePicker.date;
NSDate *fireTime = [[NSDate date] addTimeInterval:10]; // adds 10 secs
notification.fireDate = fireTime;
notification.alertBody = @"Alert!";
notification.timeZone = [NSTimeZone defaultTimeZone];
notification.applicationIconBadgeNumber = 1;
notification.soundName = UILocalNotificationDefaultSoundName;
switch (_frequencySegmentedControl.selectedSegmentIndex) {
case 0:
notification.repeatInterval = NSCalendarUnitDay;
break;
case 1:
notification.repeatInterval = NSCalendarUnitWeekOfYear;
break;
case 2:
notification.repeatInterval = NSCalendarUnitYear;
break;
default:
notification.repeatInterval = 0;
break;
}
notification.alertBody = _customMessage.text;
Once we have the notification created we need to schedule it with the app.
// this will schedule the notification to fire at the fire date
[[UIApplication sharedApplication] scheduleLocalNotification:notification];
// this will fire the notification right away, it will still also fire at the date we set
[[UIApplication sharedApplication] presentLocalNotificationNow:notification];
If we leave things the way they are now a notification will only appear on screen if the app is in the background. In order to display something when the app is in the foreground and a notification fires we need to implement a method in the app delegate.
- (void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification
{
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"Notification Received" message:notification.alertBody delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
[alertView show];
}
We added a icon badge to our app, and this icon badge will only display when the app is in the background. Generally you want to dismiss the icon once a user has opened the app and seen the notification. We’ll need to handle this in the app delegate as well.
These two methods will take care of it.
- (void)applicationWillEnterForeground:(UIApplication *)application
{
// Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
NSLog(@"%s", __PRETTY_FUNCTION__);
application.applicationIconBadgeNumber = 0;
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
NSLog(@"%s", __PRETTY_FUNCTION__);
application.applicationIconBadgeNumber = 0;
}
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