How to create local notifications?

Question

Here is sample code for LocalNotification that worked for my project.

Objective-C:

This code block in AppDelegate file :

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {
        [launchOptions valueForKey:UIApplicationLaunchOptionsLocalNotificationKey];
        // Override point for customization after application launch.
        return YES;
    }

    // This code block is invoked when application is in foreground (active-mode) 
 -(void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification {

        UIAlertView *notificationAlert = [[UIAlertView alloc] initWithTitle:@"Notification"    message:@"This local notification" 
        delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];

        [notificationAlert show];
       // NSLog(@"didReceiveLocalNotification");
    }

This code block in .m file of any ViewController:

-(IBAction)startLocalNotification {  // Bind this method to UIButton action
    NSLog(@"startLocalNotification");

    UILocalNotification *notification = [[UILocalNotification alloc] init];
    notification.fireDate = [NSDate dateWithTimeIntervalSinceNow:7];
    notification.alertBody = @"This is local notification!";
    notification.timeZone = [NSTimeZone defaultTimeZone];
    notification.soundName = UILocalNotificationDefaultSoundName;
    notification.applicationIconBadgeNumber = 10;

    [[UIApplication sharedApplication] scheduleLocalNotification:notification];    
}

The above code display an AlertView after time interval of 7 seconds when pressed on button that binds startLocalNotification If application is in background then it displays BadgeNumber as 10 and with default notification sound.

This code works fine for iOS 7.x and below but for iOS 8 it will prompt following error on console:

Attempting to schedule a local notification with an alert but haven't received permission from the user to display alerts

This means you need register for local notification. This can be achieved using:

if ([UIApplication instancesRespondToSelector:@selector(registerUserNotificationSettings:)]){

    [application registerUserNotificationSettings [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeAlert|UIUserNotificationTypeBadge|UIUserNotificationTypeSound categories:nil]];
}

You can also refer blog for local notification.

Swift:

You AppDelegate.swift file should look like this:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {    
    // Override point for customization after application launch.
    application.registerUserNotificationSettings(UIUserNotificationSettings(forTypes: UIUserNotificationType.Sound | UIUserNotificationType.Badge | UIUserNotificationType.Alert, categories: nil))

    return true
}

The swift file (say ViewController.swift) in which you want to create local notification should contain below code:

//MARK: - Button functions
func buttonIsPressed(sender: UIButton) {
    println("buttonIsPressed function called \(UIButton.description())")

    var localNotification = UILocalNotification()
    localNotification.fireDate = NSDate(timeIntervalSinceNow: 3)
    localNotification.alertBody = "This is local notification from Swift 2.0"
    localNotification.timeZone = NSTimeZone.localTimeZone()
    localNotification.repeatInterval = NSCalendarUnit.CalendarUnitMinute
    localNotification.userInfo = ["Important":"Data"];
    localNotification.soundName = UILocalNotificationDefaultSoundName
    localNotification.applicationIconBadgeNumber = 5
    localNotification.category = "Message"

    UIApplication.sharedApplication().scheduleLocalNotification(localNotification)
}


//MARK: - viewDidLoad

class ViewController: UIViewController {

    var objButton : UIButton!
    . . .

    override func viewDidLoad() {
        super.viewDidLoad()

        . . .

        objButton = UIButton.buttonWithType(.Custom) as? UIButton
        objButton.frame = CGRectMake(30, 100, 150, 40)
        objButton.setTitle("Click Me", forState: .Normal)
        objButton.setTitle("Button pressed", forState: .Highlighted)

        objButton.addTarget(self, action: "buttonIsPressed:", forControlEvents: .TouchDown)

        . . .
    }

    . . .
}

The way you use to work with Local Notification in iOS 9 and below is completely different in iOS 10.

Below screen grab from Apple release notes depicts this.

You can refer apple reference document for UserNotification.

Below is code for local notification:

Objective-C:

1. In App-delegate.h file use @import UserNotifications;

2. App-delegate should conform to UNUserNotificationCenterDelegate protocol

3. In didFinishLaunchingOptions use below code:

   UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
   [center requestAuthorizationWithOptions:(UNAuthorizationOptionBadge | UNAuthorizationOptionSound | UNAuthorizationOptionAlert)
          completionHandler:^(BOOL granted, NSError * _Nullable error) {
                 if (!error) {
                     NSLog(@"request authorization succeeded!");
                     [self showAlert];
                 }
   }];
   
   -(void)showAlert {
       UIAlertController *objAlertController = [UIAlertController alertControllerWithTitle:@"Alert" message:@"show an alert!" preferredStyle:UIAlertControllerStyleAlert];
   
       UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"OK"
         style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
           NSLog(@"Ok clicked!");
       }];
   
       [objAlertController addAction:cancelAction];
   
   
       [[[[[UIApplication sharedApplication] windows] objectAtIndex:0] rootViewController] presentViewController:objAlertController animated:YES completion:^{            
       }];
   
   }
   

4. Now create a button in any view controller and in IBAction use below code :

   UNMutableNotificationContent *objNotificationContent = [[UNMutableNotificationContent alloc] init];
   
   objNotificationContent.title = [NSString localizedUserNotificationStringForKey:@“Notification!” arguments:nil];
   
   objNotificationContent.body = [NSString localizedUserNotificationStringForKey:@“This is local notification message!“arguments:nil];
   
   objNotificationContent.sound = [UNNotificationSound defaultSound];
   
   // 4. update application icon badge number
   objNotificationContent.badge = @([[UIApplication sharedApplication] applicationIconBadgeNumber] + 1);
   
   // Deliver the notification in five seconds.
   UNTimeIntervalNotificationTrigger *trigger =  [UNTimeIntervalNotificationTrigger                                             triggerWithTimeInterval:10.f repeats:NO];       
   
   UNNotificationRequest *request = [UNNotificationRequest requestWithIdentifier:@“ten”                                                                            content:objNotificationContent trigger:trigger];
   
   // 3. schedule localNotification
   UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
   
   [center addNotificationRequest:request withCompletionHandler:^(NSError * _Nullable error) {
       if (!error) {
           NSLog(@“Local Notification succeeded“);
       } else {
           NSLog(@“Local Notification failed“);
       }
   }];
   

Swift 3:

1. In AppDelegate.swift file use import UserNotifications
2. Appdelegate should conform to UNUserNotificationCenterDelegate protocol

3. In didFinishLaunchingWithOptions use below code

   // Override point for customization after application launch.
   let center = UNUserNotificationCenter.current()
   center.requestAuthorization(options: [.alert, .sound]) { (granted, error) in
       // Enable or disable features based on authorization.
       if error != nil {
           print("Request authorization failed!")
       } else {
           print("Request authorization succeeded!")
           self.showAlert()
       }
   }
   
   
   func showAlert() {
       let objAlert = UIAlertController(title: "Alert", message: "Request authorization succeeded", preferredStyle: UIAlertControllerStyle.alert)
   
       objAlert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
       //self.presentViewController(objAlert, animated: true, completion: nil)
   
       UIApplication.shared().keyWindow?.rootViewController?.present(objAlert, animated: true, completion: nil)
   }
   

4. Now create a button in any view controller and in IBAction use below code :

   let content = UNMutableNotificationContent()
   content.title = NSString.localizedUserNotificationString(forKey: "Hello!", arguments: nil)
   content.body = NSString.localizedUserNotificationString(forKey: "Hello_message_body", arguments: nil)
   content.sound = UNNotificationSound.default()
   content.categoryIdentifier = "notify-test"
   
   let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval: 5, repeats: false)
   let request = UNNotificationRequest.init(identifier: "notify-test", content: content, trigger: trigger)
   
   let center = UNUserNotificationCenter.current()
   center.add(request)
   

In appdelegate.m file write the follwing code in applicationDidEnterBackground to get the local notification

- (void)applicationDidEnterBackground:(UIApplication *)application
{
   UILocalNotification *notification = [[UILocalNotification alloc]init];
   notification.repeatInterval = NSDayCalendarUnit;
   [notification setAlertBody:@"Hello world"];
   [notification setFireDate:[NSDate dateWithTimeIntervalSinceNow:1]];
   [notification setTimeZone:[NSTimeZone  defaultTimeZone]];
   [application setScheduledLocalNotifications:[NSArray arrayWithObject:notification]];
}

Creating local notifications are pretty easy. Just follow these steps.

1. On viewDidLoad() function ask user for permission that your apps want to display notifications. For this we can use the following code.

   UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge], completionHandler: {didAllow, error in
   })
   

2. Then you can create a button, and then in the action function you can write the following code to display a notification.

   //creating the notification content
   let content = UNMutableNotificationContent()
   
   //adding title, subtitle, body and badge
   content.title = "Hey this is Simplified iOS"
   content.subtitle = "iOS Development is fun"
   content.body = "We are learning about iOS Local Notification"
   content.badge = 1
   
   //getting the notification trigger
   //it will be called after 5 seconds
   let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)
   
   //getting the notification request
   let request = UNNotificationRequest(identifier: "SimplifiedIOSNotification", content: content, trigger: trigger)
   
   //adding the notification to notification center
   UNUserNotificationCenter.current().add(request, withCompletionHandler: nil)
   

3. Notification will be displayed, just click on home button after tapping the notification button. As when the application is in foreground the notification is not displayed. But if you are using iPhone X. You can display notification even when the app is in foreground. For this you just need to add a delegate called UNUserNotificationCenterDelegate

For more details visit this blog post: iOS Local Notification Tutorial

Updated with Swift 5 Generally we use three type of Local Notifications

1. Simple Local Notification
2. Local Notification with Action
3. Local Notification with Content

Where you can send simple text notification or with action button and attachment.

Using UserNotifications package in your app, the following example Request for notification permission, prepare and send notification as per user action AppDelegate itself, and use view controller listing different type of local notification test.

AppDelegate

import UIKit
import UserNotifications

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {

    let notificationCenter = UNUserNotificationCenter.current()
    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        //Confirm Delegete and request for permission
        notificationCenter.delegate = self
        let options: UNAuthorizationOptions = [.alert, .sound, .badge]
        notificationCenter.requestAuthorization(options: options) {
            (didAllow, error) in
            if !didAllow {
                print("User has declined notifications")
            }
        }

        return true
    }

    func applicationWillResignActive(_ application: UIApplication) {
    }
    func applicationDidEnterBackground(_ application: UIApplication) {
    }
    func applicationWillEnterForeground(_ application: UIApplication) {
    }
    func applicationWillTerminate(_ application: UIApplication) {
    }
    func applicationDidBecomeActive(_ application: UIApplication) {
        UIApplication.shared.applicationIconBadgeNumber = 0
    }


    //MARK: Local Notification Methods Starts here

    //Prepare New Notificaion with deatils and trigger
    func scheduleNotification(notificationType: String) {

        //Compose New Notificaion
        let content = UNMutableNotificationContent()
        let categoryIdentifire = "Delete Notification Type"
        content.sound = UNNotificationSound.default
        content.body = "This is example how to send " + notificationType
        content.badge = 1
        content.categoryIdentifier = categoryIdentifire

        //Add attachment for Notification with more content
        if (notificationType == "Local Notification with Content")
        {
            let imageName = "Apple"
            guard let imageURL = Bundle.main.url(forResource: imageName, withExtension: "png") else { return }
            let attachment = try! UNNotificationAttachment(identifier: imageName, url: imageURL, options: .none)
            content.attachments = [attachment]
        }

        let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)
        let identifier = "Local Notification"
        let request = UNNotificationRequest(identifier: identifier, content: content, trigger: trigger)

        notificationCenter.add(request) { (error) in
            if let error = error {
                print("Error \(error.localizedDescription)")
            }
        }

        //Add Action button the Notification
        if (notificationType == "Local Notification with Action")
        {
            let snoozeAction = UNNotificationAction(identifier: "Snooze", title: "Snooze", options: [])
            let deleteAction = UNNotificationAction(identifier: "DeleteAction", title: "Delete", options: [.destructive])
            let category = UNNotificationCategory(identifier: categoryIdentifire,
                                                  actions: [snoozeAction, deleteAction],
                                                  intentIdentifiers: [],
                                                  options: [])
            notificationCenter.setNotificationCategories([category])
        }
    }

    //Handle Notification Center Delegate methods
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification,
                                withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler([.alert, .sound])
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                didReceive response: UNNotificationResponse,
                                withCompletionHandler completionHandler: @escaping () -> Void) {
        if response.notification.request.identifier == "Local Notification" {
            print("Handling notifications with the Local Notification Identifier")
        }
        completionHandler()
    }
}

and ViewController

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    var appDelegate = UIApplication.shared.delegate as? AppDelegate
    let notifications = ["Simple Local Notification",
                         "Local Notification with Action",
                         "Local Notification with Content",]

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    // MARK: - Table view data source

     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return notifications.count
    }

     func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        cell.textLabel?.text = notifications[indexPath.row]
        return cell
    }

     func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let notificationType = notifications[indexPath.row]
        let alert = UIAlertController(title: "",
                                      message: "After 5 seconds " + notificationType + " will appear",
                                      preferredStyle: .alert)
        let okAction = UIAlertAction(title: "Okay, I will wait", style: .default) { (action) in
            self.appDelegate?.scheduleNotification(notificationType: notificationType)
        }
        alert.addAction(okAction)
        present(alert, animated: true, completion: nil)
    }
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
   UILocalNotification *notification = [[UILocalNotification alloc]init];
   notification.repeatInterval = NSDayCalendarUnit;
   [notification setAlertBody:@"Hello world"];
   [notification setFireDate:[NSDate dateWithTimeIntervalSinceNow:1]];
   [notification setTimeZone:[NSTimeZone  defaultTimeZone]];
   [application setScheduledLocalNotifications:[NSArray arrayWithObject:notification]];
}

This is worked, but in iOS 8.0 and later, your application must register for user notifications using -[UIApplication registerUserNotificationSettings:] before being able to schedule and present UILocalNotifications, do not forget this.