Android progress notifications in Kotlin

In this tutorial you’ll learn how to create a basic Progress Notification (Indeterminate progress indicator and Fixed-duration progress indicator) for Android using Kotlin.

Before we begin, let us first understand the components of a Notification in Android.

1. Small Icon – Required, can be set with setSmallIcon().
2. Application Name – Provided by the system.
3. Time Stamp – Provided by the system but can be overridden.
4. Large Icon – Optional, can be set with setLargeIcon().
5. Title – Optional, can be set with setContentTitle().
6. Text – Optional, can be set with setContentText().

Note : Notification Channels
Since the introduction of Android version 8 (Android Oreo), it is now compulsory to categorize all the notifications into categories called ‘channels’, this is for the convenience of users and also developers.
The image below shows us a notification channel named ‘Progress Notification’.

Since we only need to create a channel once, we’ll use a helper class ‘App.kt’ to get the job done.

App.kt

package com.gfg.progressnotificationdemo

import android.app.Application
import android.app.NotificationChannel
import android.app.NotificationManager
import android.os.Build

class App : Application(){
    val channelId = "Progress Notification" as String

    override fun onCreate(){
        super.onCreate()
        createNotificationChannels()
    }

    //Check if the Android version is greater than 8. (Android Oreo)
    private fun createNotificationChannels(){
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel1 = NotificationChannel(
                channelId,
                "Progress Notification",
    //IMPORTANCE_HIGH = shows a notification as peek notification.
    //IMPORTANCE_LOW = shows the notification in the status bar.
                NotificationManager.IMPORTANCE_HIGH
            )
            channel1.description = "Progress Notification Channel"
            val manager = getSystemService(
                NotificationManager::class.java
            )
            manager.createNotificationChannel(channel1)
        }
    }
}

Now, in the main activity we'll use a thread to invoke the notification.

MainActivity.kt

package com.gfg.progressnotificationdemo

import android.app.PendingIntent
import android.content.Intent
import android.os.Bundle
import android.os.SystemClock
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import com.gfg.progressnotificationdemo.R.drawable


class MainActivity : AppCompatActivity(){

    private lateinit var notificationManager: NotificationManagerCompat
    val channelId = "Progress Notification" as String

    override fun onCreate(savedInstanceState: Bundle?){
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

    //Create a Notification Manager
        notificationManager = NotificationManagerCompat.from(this)

    }

    //Start() is called when the buttons is pressed.
    public fun start(view: View){

        val intent = Intent(this, MainActivity::class.java).apply{
            flags = Intent.FLAG_ACTIVITY_NEW_TASK or
            Intent.FLAG_ACTIVITY_CLEAR_TASK
        }

        val pendingIntent: PendingIntent = PendingIntent.getActivity(
         this, 0, intent, 0)

    //Sets the maximum progress as 100
        val progressMax = 100
    //Creating a notification and setting its various attributes
        val notification =
            NotificationCompat.Builder(this, channelId)
                .setSmallIcon(drawable.ic_file_download)
                .setContentTitle("GeeksforGeeks")
                .setContentText("Downloading")
                .setPriority(NotificationCompat.PRIORITY_LOW)
                .setOngoing(true)
                .setOnlyAlertOnce(true)
                .setProgress(progressMax, 0, true)
                .setContentIntent(pendingIntent)
                .setAutoCancel(true)

    //Initial Alert
        notificationManager.notify(1, notification.build())

        Thread(Runnable{
            SystemClock.sleep(2000)
            var progress = 0
            while (progress <= progressMax) {
                SystemClock.sleep(
                    1000
                )
                progress += 20
    //Use this to make it a Fixed-duration progress indicator notification

    //notification.setContentText(progress.toString()+"%")
    //.setProgress(progressMax, progress, false)

    //notificationManager.notify(1, notification.build())
            }

            notification.setContentText("Download complete")
                .setProgress(0, 0, false)
                .setOngoing(false)
            notificationManager.notify(1, notification.build())
        }).start()
    }
}

Activity Main.xml

Layout consists of a single button.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="75dp"
        android:onClick="start"
        android:text="Show Notification"
        android:textSize="22sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Output:

• Fixed-duration progress indicator : (after adding code in comments at line 67 of MainActivity.kt)
  
  
• Indeterminate progress indicator :
  
  
• After Download :
  
  

That’s how easy and simple it is to add progress indicator to a notification in Android using Kotlin.