How to display count of notifications in the Android App launcher using Kotlin?

This example demonstrates how to display count of notifications in the Android App launcher using Kotlin.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity">    <TextView       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_centerHorizontal="true"       android:layout_marginTop="50dp"       android:text="Tutorials Point"       android:textAlignment="center"       android:textColor="@android:color/holo_green_dark"       android:textSize="32sp"       android:textStyle="bold" />    <Button       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_centerInParent="true"       android:onClick="createNotification"       android:text="create notification" /> </RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.app.NotificationChannel import android.app.NotificationManager import android.app.PendingIntent import android.content.Context import android.content.Intent import android.os.Build import android.os.Bundle import android.view.View import androidx.appcompat.app.AppCompatActivity import androidx.core.app.NotificationCompat class MainActivity : AppCompatActivity() {    var count = 0    private val channelId = "10001"    private val defaultChannelId = "default"    override fun onResume() {       super.onResume()       count = 0    }    override fun onCreate(savedInstanceState: Bundle?) {       super.onCreate(savedInstanceState)       setContentView(R.layout.activity_main)       title = "KotlinApp"    }    fun createNotification(view: View) {       count++       val notificationIntent = Intent(applicationContext, MainActivity::class.java)       notificationIntent.putExtra("fromNotification", true)       notificationIntent.flags = Intent.FLAG_ACTIVITY_CLEAR_TOP or       Intent.FLAG_ACTIVITY_SINGLE_TOP       val pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0)       val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as       NotificationManager       val builder = NotificationCompat.Builder(applicationContext, defaultChannelId)       builder.setContentTitle("My Notification")       builder.setContentIntent(pendingIntent)       builder.setContentText("Notification Listener Service Example")       builder.setSmallIcon(R.drawable.ic_launcher_foreground)       builder.setAutoCancel(true)       builder.setBadgeIconType(NotificationCompat.BADGE_ICON_SMALL)       builder.setNumber(count)       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {          val importance = NotificationManager.IMPORTANCE_HIGH          val notificationChannel = NotificationChannel(channelId,          "NOTIFICATION_CHANNEL_NAME", importance)          builder.setChannelId(channelId)          notificationManager.createNotificationChannel(notificationChannel)       }       notificationManager.notify(System.currentTimeMillis().toInt(), builder.build())    } }

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.q11"> <uses-permission android:name="android.permission.VIBRATE" /> <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />    <application       android:allowBackup="true"       android:icon="@mipmap/ic_launcher"       android:label="@string/app_name"       android:roundIcon="@mipmap/ic_launcher_round"       android:supportsRtl="true"       android:theme="@style/AppTheme">       <activity android:name=".MainActivity">          <intent-filter>             <action android:name="android.intent.action.MAIN" />             <category android:name="android.intent.category.LAUNCHER" />          </intent-filter>       </activity>    </application> </manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen