KMPNotifier - Kotlin Multiplatform Push Notification

Simple and easy to use Kotlin Multiplatform Push Notification library (using Firebase Cloud Messaging) targeting ios and android and Local Notification targetting android, ios, desktop and web (js and wasm).
This library is used in FindTravelNow production KMP project. You can check out Documentation for full library api information.

Related Blog Posts
KMPNotifier Update: Web, Desktop, and New Features for Kotlin Multiplatform Notifications
How to implement Push Notifications in Kotlin Multiplatform

Features

• 🔔 Local Notification (android, ios, desktop, js and wasm targets)
• 🔔 Push Notification (Firebase Cloud Messaging) (android and ios only)
• 📱 Multiplatform (android, iOS, desktop and web (js and wasm))

Installation

Before starting you need to setup basic setup using Firebase official guideline (like initializing project in Firebase, adding google-services.json to android, GoogleService-Info.plist to iOS).

Minimum Requirements

• Android: minSdkVersion 21
• iOS: iOS 14.1

Gradle Setup

KMPNotifier is available on Maven Central. In your root project build.gradle.kts file (or settings.gradle file) add mavenCentral() to repositories, and add google-services plugin to plugins.

plugins {
  id("com.android.application") version "8.1.3" apply false
  id("org.jetbrains.kotlin.multiplatform") version "1.9.20" apply false
  id("com.google.gms.google-services") version "4.4.0" apply false
}

repositories { 
  mavenCentral()
}

Then in your shared module you add dependency in commonMain. Latest version: . In iOS framework part export this library as well.

sourceSets {
  commonMain.dependencies {
    api("io.github.mirzemehdi:kmpnotifier:<version>") // in iOS export this library
  }
}

listOf(iosX64(),iosArm64(),iosSimulatorArm64()).forEach { iosTarget ->
  iosTarget.binaries.framework {
    export("io.github.mirzemehdi:kmpnotifier:<version>")
    ...
  }
}

And in androidApp build.gradle.kts file you apply google-services plugin

plugins {
  id("com.android.application")
  id("com.google.gms.google-services")
}

Platform Setup

In all platforms on Application Start you need to initialize library using

//passing android, ios, desktop or web configuration depending on the platform
NotifierManager.initialize(NotificationPlatformConfiguration)  

Android

Android Setup

class MyApplication : Application() {
   override fun onCreate() {
       super.onCreate()
       /**
        * By default showPushNotification value is true.
        * When set showPushNotification to false foreground push  notification will not be shown to user.
        * You can still get notification content using #onPushNotification listener method.
        */
       NotifierManager.initialize(
           configuration = NotificationPlatformConfiguration.Android(
               notificationIconResId = R.drawable.ic_launcher_foreground,
               showPushNotification = true,
           )
       )
   }
}

Also starting from Android 13(API Level 33) you need to ask runtime POST_NOTIFICATIONS in activity. I created utility function that you can use in activity.

val permissionUtil by permissionUtil()
permissionUtil.askNotificationPermission() //this will ask permission in Android 13(API Level 33) or above, otherwise permission will be granted.

iOS

iOS Setup

First you just need to include FirebaseMessaging library to your ios app from Xcode. Then on application start you need to call both FirebaseApp initialization and NotifierManager initialization methods, and apnsToken setting as below. Don't forget to add Push Notifications and Background Modes (Remote Notifications) signing capability in Xcode.

import SwiftUI
import shared
import FirebaseCore
import FirebaseMessaging

class AppDelegate: NSObject, UIApplicationDelegate {

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

      FirebaseApp.configure() //important
      
      //By default showPushNotification value is true.
      //When set showPushNotification to false foreground push  notification will not be shown.
      //You can still get notification content using #onPushNotification listener method.
      NotifierManager.shared.initialize(configuration: NotificationPlatformConfigurationIos(showPushNotification: true))
      
    return true
  }

  func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        Messaging.messaging().apnsToken = deviceToken
  }
    
}

@main
struct iOSApp: App {
    
    @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate
    
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

Desktop

Desktop Setup

You need to put notification icon into resources/common folder. For more information:
Compose Desktop Resources

fun main() = application {

   NotifierManager.initialize(
       NotificationPlatformConfiguration.Desktop(
           showPushNotification = true,
           notificationIconPath = composeDesktopResourcesPath() + File.separator + "ic_notification.png"
       )
   )
   
   AppInitializer.onApplicationStart()
   Window(
       onCloseRequest = ::exitApplication,
       title = "KMPNotifier Desktop",
   ) {
       println("Desktop app is started")
       App()

   }
}

Web

Web Setup (Js and Wasm)

On application start initialize it using Web configuration

fun main()  {

   NotifierManager.initialize(
       NotificationPlatformConfiguration.Web(
           askNotificationPermissionOnStart = true,
           notificationIconPath = null
       )
   )
   
}

Note: If you are using mac make sure you also allow notifications for browser from system system settings in order to see web notifications.

Usage

You can send either local or push notification.

Local Notification

Local notifications are supported on Android, iOS, JS and wasm targets.

Send notification

val notifier = NotifierManager.getLocalNotifier()
val notificationId = notifier.notify("Title", "Body") 
// or you can use below to specify ID yourself
notifier.notify(1, "Title", "Body")

Remove notification by Id or all notifications

notifer.remove(notificationId) //Removes notification by Id  

notifier.removeAll() //Removes all notification

Push Notification

Push notifications are supported only for Android and iOS.

Listen for push notification token changes

In this method you can send notification token to the server.

NotifierManager.addListener(object : NotifierManager.Listener {
  override fun onNewToken(token: String) {
    println("onNewToken: $token") //Update user token in the server if needed
  }
}) 

Receive notification type messages

NotifierManager.addListener(object : NotifierManager.Listener {
  override fun onPushNotification(title:String?,body:String?) {
    println("Push Notification notification title: $title")
  }
}) 

Receive data payload

NotifierManager.addListener(object : NotifierManager.Listener {
  override fun onPayloadData(data: PayloadData) {
    println("Push Notification payloadData: $data") //PayloadData is just typeAlias for Map<String,*>.
  }
}) 

And you need to call below platform-specific functions in order to receive payload data properly.

Android

Call NotifierManager.onCreateOrOnNewIntent(intent) on launcher Activity's onCreate and onNewIntent methods.

override fun onCreate(savedInstanceState: Bundle?) {
   super.onCreate(savedInstanceState)
      NotifierManager.onCreateOrOnNewIntent(intent)
      ...
    }

    override fun onNewIntent(intent: Intent?) {
        super.onNewIntent(intent)
        NotifierManager.onCreateOrOnNewIntent(intent)
    }

iOS

Call NotifierManager.onApplicationDidReceiveRemoteNotification(userInfo: userInfo) on application's didReceiveRemoteNotification method.

 func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any]) async -> UIBackgroundFetchResult {
      NotifierManager.shared.onApplicationDidReceiveRemoteNotification(userInfo: userInfo)
      return UIBackgroundFetchResult.newData
 }

Detecting notification click and get payload data

Make sure you follow previous step for getting payload data properly.

NotifierManager.addListener(object : NotifierManager.Listener {
    override fun onNotificationClicked(data: PayloadData) {
        super.onNotificationClicked(data)
        println("Notification clicked, Notification payloadData: $data")
    }
}) 

Other functions

NotifierManager.getPushNotifier().getToken() //Get current user push notification token
NotifierManager.getPushNotifier().deleteMyToken() //Delete user's token for example when user logs out 
NotifierManager.getPushNotifier().subscribeToTopic("new_users") 
NotifierManager.getPushNotifier().unSubscribeFromTopic("new_users") 

For setting custom notification sound, check #61 (comment)
For setting Intent data in Android (for deeplink), check #60 (comment)
For permissionUtil, or manually asking notification permission check #27 (comment)