Not able to add TextView using Relative Layout.

[parita-detroja]

I am creating location based AR app using Kotlin, in which i used RelativeLayout and added TextView in that RelativeLayout as below code.

class AROverlayByViewGroup(context: Context) : RelativeLayout(context) { val TAG: String = "AROverlayByViewGroup" var rotatedProjectionMatrix: FloatArray = kotlin.FloatArray(16) private var currentLocation: Location? = null var arPoints: MutableList = ArrayList() val cameraCoordinateVector: FloatArray = kotlin.FloatArray(4)

var parentHeight: Int? = null
var parentWidth: Int? = null

fun updateARPoints(arPoints: MutableList<ARPoint>)
{
    this.arPoints = arPoints
}

fun updateRotatedProjectionMatrix(rotatedProjectionMatrix: FloatArray)
{
    this.rotatedProjectionMatrix = rotatedProjectionMatrix
}

fun updateCurrentLocation(location: Location)
{
    this.currentLocation = location
    this.invalidate()
}

override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {

    if (currentLocation == null) {
        return
    }

    for ((location, name) in arPoints) {
        val currentLocationInECEF: FloatArray = LocationHelper.WSG84toECEF(currentLocation!!)
        val pointInECEF: FloatArray = LocationHelper.WSG84toECEF(location)
        val pointInENU: FloatArray = LocationHelper.ECEFtoENU(currentLocation!!, currentLocationInECEF, pointInECEF)

        Matrix.multiplyMV(cameraCoordinateVector, 0, rotatedProjectionMatrix, 0, pointInENU, 0)

        if (cameraCoordinateVector[2] < 0) {

            val x: Float = (0.5f + cameraCoordinateVector[0] / cameraCoordinateVector[3]) * parentWidth!!
            val y: Float = (0.5f - cameraCoordinateVector[1] / cameraCoordinateVector[3]) * parentHeight!!

            val mTextView: TextView = TextView(this.context)
            mTextView.text = name
            mTextView.setTextColor(Color.BLUE)
            mTextView.textSize = 50F

            val params = RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT,
                    RelativeLayout.LayoutParams.WRAP_CONTENT)
            params.leftMargin = x.toInt()
            params.topMargin = y.toInt()

            this.addView(mTextView, params)

        }
    }
}

override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec)

    parentWidth = MeasureSpec.getSize(widthMeasureSpec)
    parentHeight = MeasureSpec.getSize(heightMeasureSpec)

    Log.e(TAG, "width: " + parentWidth.toString())
    Log.e(TAG, "height: " + parentHeight.toString())
}

}

I am not getting any textview. What do i need to change for this?