Android Bad notification posted Crash

Question

I'm new to coding. I have made a net speed indicator app for fun. It displays the network speed as a status bar icon. It also allows users to set data usage limits (like 100 GB per month) and sends a notification when they reach the limit.

The final output looks like this:

I followed this answer to display the status bar icon.

Here is the Notifications class I use:

class Notifications(private val context: Context) {

    private val notificationChannelPrimary =
        "Primary Channel Notification" // This is the persistent channel that shows live data usage
    val notificationPersistentChannelID = 15 // To send notifications of persistent channel
    private val notificationChannelDataLimit = "Data Limit Warning Notifications"
    private val notificationDataLimitID = 10

    private val intentNotification = Intent(context, MainActivity::class.java)
    private val notificationManager =
        context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager

    private var mNotificationBuilder: Notification.Builder? = null

    private var tempValues = arrayOf(String())

    // The following variables are for creating status bar icon
    private val bitmap = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888)
    private val canvas = Canvas(bitmap)
    private val paintSpeed = Paint() // This is for speed value
    private val paintUnit = Paint() // This is for speed unit

    init {
        // Set the paint styles
        paintSpeed.color = Color.WHITE
        paintSpeed.isAntiAlias = true
        paintSpeed.textSize = 60f
        paintSpeed.textAlign = Paint.Align.CENTER
        paintSpeed.typeface = Typeface.DEFAULT_BOLD
        paintUnit.color = Color.WHITE
        paintUnit.isAntiAlias = true
        paintUnit.textSize = 40f
        paintUnit.textAlign = Paint.Align.CENTER
        paintUnit.typeface = Typeface.DEFAULT_BOLD

        createNotificationChannel()

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            mNotificationBuilder =
                getNotificationBuilder()
        }
    }

    // This method sets the speed to zero when the device is offline
    fun setZeroSpeed() {
        canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR)
        canvas.drawText("0", 48f, 52f, paintSpeed)
        canvas.drawText("Kb/s", 48f, 95f, paintUnit)
        try {
            mNotificationBuilder?.setSmallIcon(Icon.createWithBitmap(bitmap))
            notificationManager.notify(notificationPersistentChannelID, mNotificationBuilder?.build())
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

    // This method shows the speed + data usage on the notification
    // It is called every second (from a worker thread)
    fun updateDataUsage(
        dataSpeed: Long,
        remainingData: String?,
        planDetails: String?
    ) {

        canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR)

        // BytesConversion.convertSpeed() method takes long value and returns speed with unit array (like 2 Mb/s)
        tempValues = BytesConversion.convertSpeed(dataSpeed)
        canvas.drawText(tempValues[0], 50f, 50f, paintSpeed)
        canvas.drawText(tempValues[1], 50f, 95f, paintUnit)

        // If the argument of setContentTitle is null, it's not displaying anything in the title
        mNotificationBuilder?.setContentTitle(remainingData)
        mNotificationBuilder?.setContentText(planDetails)
        try {
            mNotificationBuilder?.setSmallIcon(Icon.createWithBitmap(bitmap))
            notificationManager.notify(notificationPersistentChannelID, mNotificationBuilder?.build())
        } catch (e: Exception) {

        }
    }

    // This method sends notifications when the data usage limit is reached
    // You don't need to check supported or unsupported
    // because it works in all the devices
    // It's just a normal notification
    fun sendDataLimitWarning(dataUsageTitle: String?, dataUsageDescription: String?) {
        val notificationDataLimit = getNotificationBuilderDataLimit()
        notificationDataLimit.setContentText(dataUsageDescription)
        notificationDataLimit.setContentTitle(dataUsageTitle)
        notificationManager.notify(
            notificationDataLimitID,
            notificationDataLimit.build()
        )
    }

    // Notification channel is only available from Android Oreo
    // So, check the condition
    private fun createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

            val notificationChannels = mutableListOf<NotificationChannel>()

            val notificationChannel1 = NotificationChannel(
                notificationChannelPrimary, "Persistent Notification",
                NotificationManager.IMPORTANCE_HIGH
            )
            notificationChannel1.description = "Notification that shows data usage and speed"
            notificationChannel1.lockscreenVisibility = Notification.VISIBILITY_PUBLIC

            val notificationChannel2 = NotificationChannel(
                notificationChannelDataLimit, "Data Limit Warning",
                NotificationManager.IMPORTANCE_HIGH
            )
            notificationChannel2.description = "Notification that shows data limit warnings"
            notificationChannel2.lockscreenVisibility = Notification.VISIBILITY_PUBLIC
            notificationChannel2.enableVibration(true)
            notificationChannel2.enableLights(true)

            notificationChannels.add(notificationChannel1)
            notificationChannels.add(notificationChannel2)

            notificationManager.createNotificationChannels(notificationChannels)
        }
    }

    // This is for sending data limit warnings
    private fun getNotificationBuilderDataLimit(): NotificationCompat.Builder {

        val pendingIntentDataLimit = PendingIntent.getActivity(
            context,
            notificationDataLimitID,
            intentNotification,
            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
        )

        return NotificationCompat.Builder(
            context,
            notificationChannelDataLimit
        )
            .setContentTitle("Data Limit Warning")
            .setSmallIcon(R.drawable.icon_notification)
            .setColor(ContextCompat.getColor(context, R.color.primary_color))
            .setContentIntent(pendingIntentDataLimit)
            .setDefaults(NotificationCompat.DEFAULT_ALL)
            .setPriority(NotificationManager.IMPORTANCE_HIGH)
    }

    // This is for sending data + speed notification
    // Speed indicator requires Notification.Builder
    @RequiresApi(Build.VERSION_CODES.O)
    fun getNotificationBuilder(
    ): Notification.Builder {

        val pendingIntentNotification = PendingIntent.getActivity(
            context,
            notificationPersistentChannelID,
            intentNotification,
            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
        )

        return Notification.Builder(
            context,
            notificationChannelPrimary
        )
            .setSmallIcon(R.drawable.icon_notification)
            .setContentIntent(pendingIntentNotification)
            .setAutoCancel(false)
            .setStyle(Notification.BigTextStyle())
            .setOnlyAlertOnce(true)
            .setColor(ContextCompat.getColor(context, R.color.primary_color))
    }
}

The problem is that I'm getting the following crashes a lot.

Fatal Exception: android.app.RemoteServiceException: Bad notification(tag=null, id=15) posted from package [package_name], crashing app(uid=10769, pid=16295): Couldn't inflate contentViewsjava.util.ConcurrentModificationException
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1894)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loop(Looper.java:214)
       at android.app.ActivityThread.main(ActivityThread.java:7156)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)

and

Fatal Exception: android.app.RemoteServiceException: Bad notification(tag=null, id=15) posted from package [package_name], crashing app(uid=10337, pid=27920): Couldn't inflate contentViewsjava.lang.ArrayIndexOutOfBoundsException: src.length=8 srcPos=0 dst.length=8 dstPos=2 length=8
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2168)
       at android.os.Handler.dispatchMessage(Handler.java:107)
       at android.os.Looper.loop(Looper.java:227)
       at android.app.ActivityThread.main(ActivityThread.java:7822)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1026)

I searched for "Bad notification posted crash", I found that mNotificationBuilder.setSmallIcon() argument must be a PNG icon (I'm calling it in updateDataUsage() method). Can someone please tell me how to convert the bitmap to PNG and pass it to setSmallIcon()?