Create Notification Alerts in Android Studio with Kotlin

Last updated Dec 21, 2021

In this android example , we will see how to create a notification alert in Android Studio by using Kotlin Language.

A notification is a message that can be displayed to the user outside of the standard UI of your programme. When you instruct the system to send a notification, it displays as an icon in the notification area at first. The user opens the notification drawer to view the notification's details.

IMPLEMENTATION:

Step 1: Create a new Project in android studio.

Go to File > New > New Project > Empty Activity > Next > Enter Name > Select Language Kotlin > Finish

Step 2. Go to activity_main.xml file and add the following code

Step 3. Open MainActivity.kt file and add the following code.

lateinit var notificationChannel: NotificationChannel
lateinit var notificationManager: NotificationManager
lateinit var builder: Notification.Builder
private val channelId = "1000"
private val description = "Kotlin Demo Notification"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val btn = findViewById(R.id.btn)
notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as
NotificationManager

btn.setOnClickListener {
val intent = Intent(this, AfterNotification::class.java)
val pendingIntent =
PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
notificationChannel =
NotificationChannel(channelId, description, NotificationManager.IMPORTANCE_HIGH)
notificationChannel.lightColor = Color.BLUE
notificationChannel.enableVibration(true)
notificationManager.createNotificationChannel(notificationChannel)
builder = Notification.Builder(this, channelId).setContentTitle(
"Notification Alert "
).setContentText("Kotlin Demo Notification")
.setSmallIcon(R.drawable.ic_baseline_settings_24).setLargeIcon(
BitmapFactory.decodeResource(
this.resources, R.drawable
.ic_launcher_background
)
).setContentIntent(pendingIntent)
}
notificationManager.notify(1000, builder.build())
}
}

In the above code we created NotificationChannel, what is Notification Channel, From android version 8 and above we need to create a channel for Notifications which will give access to similar notifications will comes under same group and user can enable/disable respected notifications based on Notification channel.

Build.VERSION_CODES.O - is a reference to API level 26 (Android Oreo which is Android 8)
if ((Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) is TRUE - means the device running the app has Android SDK 26 or up - and the Block of code inside you "if" statement will be executed.

Notification Builder and Notification Properties:
Once you have Builder object, you can set its Notification properties using Builder object as per your requirement. But this is mandatory to set at least following −

A small icon, set by setSmallIcon()
A title, set by setContentTitle()
Detail text, set by setContentText()

builder = Notification.Builder(this, channelId).setContentTitle(
                    "Notification Alert "
                ).setContentText("Kotlin Demo Notification")
                    .setSmallIcon(R.drawable.ic_baseline_settings_24).setLargeIcon(
                        BitmapFactory.decodeResource(
                            this.resources, R.drawable
                                .ic_launcher_background
                        )
                    ).setContentIntent(pendingIntent)
            }

You pass the Notification object to the system by calling NotificationManager.notify() to send your notification.

notificationManager.notify(1000, builder.build())

Step 5: Create a new Empty Activity and enter name (AfterNotificationActivity) and Finish.

Step6: Open activity_after_notification.xml and add the following code

<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=".AfterNotification">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Welcome To RRTutors"
        android:textSize="15sp"
        android:textStyle="bold" />

</RelativeLayout>

Step 4. Run the app on emulator or real device, you will get the output as in Video.

Complete Source Code of Detect Connected Network type Android Example

activity_main.xml file

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">
    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Show Notification" />
</RelativeLayout>

MainActivity.kt file

import android.app.*
import android.content.Context
import android.content.Intent
import android.graphics.BitmapFactory
import android.graphics.Color
import android.os.Build
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Button

class MainActivity : AppCompatActivity() {
lateinit var notificationChannel: NotificationChannel
lateinit var notificationManager: NotificationManager
lateinit var builder: Notification.Builder
private val channelId = "1000"
private val description = "Kotlin Demo Notification"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val btn = findViewById(R.id.btn)
notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as
NotificationManager

btn.setOnClickListener {
val intent = Intent(this, LauncherActivity::class.java)
val pendingIntent =
PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
notificationChannel =
NotificationChannel(channelId, description, NotificationManager.IMPORTANCE_HIGH)
notificationChannel.lightColor = Color.BLUE
notificationChannel.enableVibration(true)
notificationManager.createNotificationChannel(notificationChannel)
builder = Notification.Builder(this, channelId).setContentTitle(
"Notification Alert "
).setContentText("Kotlin Demo Notification")
.setSmallIcon(R.drawable.ic_baseline_settings_24).setLargeIcon(
BitmapFactory.decodeResource(
this.resources, R.drawable
.ic_launcher_background
)
).setContentIntent(pendingIntent)
}
notificationManager.notify(1000, builder.build())
}
}
}

activity_after_notification.xml file

<?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=".AfterNotification">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Welcome To RRTutors"
        android:textSize="15sp"
        android:textStyle="bold" />

</RelativeLayout>

Conclusion : In this article we have covered how to create a notification alert and show on a click of button in Android Studio by using Kotlin Language.