Delete a particular local notification

Question

I am developing an iPhone alarm app based on local notifications.

On deleting an alarm, the related local notification should get cancelled. But how can I determine exactly which object from the array of local notifications is to be cancelled?

I am aware of [[UIApplication sharedApplication] cancelLocalNotification:notification] method but how can I get this 'notification' to cancel it?

Answer 1

You can save a unique value for key in your local notification's userinfo. Get all local notification, loop through the array and delete the particular notification.

Code as follows,

OBJ-C:

UIApplication *app = [UIApplication sharedApplication]; NSArray *eventArray = [app scheduledLocalNotifications]; for (int i=0; i<[eventArray count]; i++) {     UILocalNotification* oneEvent = [eventArray objectAtIndex:i];     NSDictionary *userInfoCurrent = oneEvent.userInfo;     NSString *uid=[NSString stringWithFormat:@"%@",[userInfoCurrent valueForKey:@"uid"]];     if ([uid isEqualToString:uidtodelete])     {         //Cancelling local notification         [app cancelLocalNotification:oneEvent];         break;     } } 

SWIFT:

var app:UIApplication = UIApplication.sharedApplication() for oneEvent in app.scheduledLocalNotifications {     var notification = oneEvent as UILocalNotification     let userInfoCurrent = notification.userInfo! as [String:AnyObject]     let uid = userInfoCurrent["uid"]! as String     if uid == uidtodelete {         //Cancelling local notification         app.cancelLocalNotification(notification)         break;     } } 

UserNotification:

If you use UserNotification (iOS 10+), just follow this steps:

1. When creating the UserNotification content, add an unique identifier

2. Remove specific pending notification using removePendingNotificationRequests(withIdentifiers:)

3. Remove specific delivered notification using removeDeliveredNotifications(withIdentifiers:)

For more info, UNUserNotificationCenter

Answer 2

Other Option:

First of All, when you create local notification, you can store it in user defaults for future use, Local notification object can not be stored directly in user defaults, This object needs to be converted into NSData object first, and then NSData can be stored into User defaults. Below is code for that:

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:localNotif]; [[NSUserDefaults standardUserDefaults] setObject:data forKey:[NSString  stringWithFormat:@"%d",indexPath.row]]; 

After you have stored and scheduled local notification, In future, requirement may arise that you need to cancel any of notification that you created earlier, So you can retrieve it from User defaults.

NSData *data= [[NSUserDefaults standardUserDefaults] objectForKey:[NSString   stringWithFormat:@"%d",UniqueKey]];  UILocalNotification *localNotif = [NSKeyedUnarchiver unarchiveObjectWithData:data]; NSLog(@"Remove localnotification  are %@", localNotif); [[UIApplication sharedApplication] cancelLocalNotification:localNotif]; [[NSUserDefaults standardUserDefaults] removeObjectForKey:[NSString stringWithFormat:@"%d",UniqueKey]]; 

Hope This helps