Implementing Push Notifications in Swift

Introduction

Push notifications are an essential feature for modern mobile applications, allowing developers to engage users with timely updates and information. Utilizing push notifications can significantly enhance user experience, retention, and interaction with your app. In this article, we will explore three diverse examples of implementing push notifications in Swift, covering different use cases to help you understand how to integrate this feature into your iOS applications.

Example 1: Basic Push Notification Setup

Context

This example demonstrates the basic setup for push notifications in a Swift-based iOS app. It covers how to request permission from the user and register the device for remote notifications.

import UIKit
import UserNotifications

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSDictionary?]) -> Bool {
        // Request permission for notifications
        UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .badge, .sound]) { granted, error in
            if granted {
                print("Permission granted")
            } else {
                print("Permission denied")
            }
        }

        // Register for remote notifications
        application.registerForRemoteNotifications()
        return true
    }

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        // Convert device token to string
        let tokenParts = deviceToken.map { data in String(format: "%02.2hhx", data) }
        let token = tokenParts.joined()
        print("Device Token: \(token)")
    }

    func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
        print("Failed to register: \(error)")
    }
}

Notes

• Make sure to enable push notifications capability in your Xcode project settings.
• Test on a physical device, as push notifications do not work in the simulator.

Example 2: Handling Incoming Notifications

Context

Once you have set up notifications, the next step is to handle incoming notifications. This example illustrates how to receive and display notifications when the app is in the foreground or background.

import UIKit
import UserNotifications

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {
    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSDictionary?]) -> Bool {
        UNUserNotificationCenter.current().delegate = self
        return true
    }

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

    // Handle background notifications
    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
        let userInfo = response.notification.request.content.userInfo
        print("Received notification: \(userInfo)")
        completionHandler()
    }
}

Notes

• The willPresent method allows you to show notifications while the app is in the foreground.
• Customize the notification handling as needed based on the user’s interaction.

Example 3: Sending Local Notifications

Context

In addition to remote notifications, you can send local notifications to users. This example illustrates how to create and schedule a local notification using Swift.

import UIKit
import UserNotifications

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        scheduleLocalNotification()
    }

    func scheduleLocalNotification() {
        let content = UNMutableNotificationContent()
        content.title = "Reminder"
        content.body = "Don't forget to check your app!"
        content.sound = UNNotificationSound.default

        // Configure the trigger for a 5 seconds delay
        let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)

        // Create the request
        let request = UNNotificationRequest(identifier: "LocalNotification", content: content, trigger: trigger)

        // Schedule the request with the system
        UNUserNotificationCenter.current().add(request) { error in
            if let error = error {
                print("Error scheduling notification: \(error)")
            }
        }
    }
}

Notes

• This example schedules a notification to appear 5 seconds after the app is loaded.
• Local notifications are particularly useful for reminders or alerts that don’t require server communication.