NotificationHelper.kt

// How to use it
// just call this
NotificationHelper.Builder(requireContext())
                .setTitle("Hello")
                .setDescription("Tourism is travel for pleasure or business; also the theory and practice")
                .build()


class NotificationHelper private constructor(builder: Builder) {

    init {
        notify(builder.context, builder.title, builder.description)
    }

    companion object {
        const val CHANNEL_ID = "1"
    }

    private fun notify(context: Context, textTitle: String, textContent: String) {

        // Create an explicit intent for an Activity in your app
        val intent = Intent(context, SplashActivity::class.java).apply {
            flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
        }
        val pendingIntent: PendingIntent = PendingIntent.getActivity(context, 0, intent, 0)

        createNotificationChannel(context)

        val builder = NotificationCompat.Builder(context, CHANNEL_ID)
                .setSmallIcon(R.drawable.ic_logo_icon)
                .setContentTitle(textTitle)
                .setContentText(textContent)
                .setContentIntent(pendingIntent)
                .setPriority(NotificationCompat.PRIORITY_HIGH)
                .setStyle(NotificationCompat.BigTextStyle())

        with(NotificationManagerCompat.from(context)) {
            // notificationId is a unique int for each notification that you must define
            notify(1, builder.build())
        }

    }


    private fun createNotificationChannel(context: Context) {
        // Create the NotificationChannel, but only on API 26+ because
        // the NotificationChannel class is new and not in the support library
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

            val name = context.getString(R.string.channel_name)
            val descriptionText = context.getString(R.string.channel_description)
            val importance = NotificationManager.IMPORTANCE_HIGH
            val channel = NotificationChannel(CHANNEL_ID, name, importance).apply {
                description = descriptionText
            }

            // Register the channel with the system
            val notificationManager: NotificationManager =
                    context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            notificationManager.createNotificationChannel(channel)
        }
    }

    class Builder(val context: Context) {

        var title: String = "Alfateha title"
            private set

        var description: String = "Alfateha description"
            private set

        fun setTitle(title: String): Builder {
            this.title = title
            return this
        }

        fun setDescription(description: String): Builder {
            this.description = description
            return this
        }

        fun build() {
            NotificationHelper(this)
        }

    }
}

NotificationHelper is a class is build with builder design pattern to push a noti to the use.