How can i get current device DPI values programatically in android using kotlin

<?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=".SDkVersion">

          <TextView
              android:id="@+id/txt_info"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_centerHorizontal="true"
              android:layout_marginBottom="50dp"
              android:text=""
              android:textAlignment="center"
              android:textColor="@android:color/holo_green_dark"
              android:textSize="32sp"
              android:textStyle="bold"
              app:layout_constraintBottom_toTopOf="@+id/button"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintStart_toStartOf="parent" />



          <Button
              android:id="@+id/button"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="Get DPI Values"
              android:onClick="getInfo"
              app:layout_constraintBottom_toBottomOf="parent"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintStart_toStartOf="parent"
              app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

package rrtutors.com.androidtopactivity

import android.os.Build
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.DisplayMetrics
import android.view.View
import android.widget.TextView

class SDkVersion : AppCompatActivity() {
    lateinit var txt_info:TextView
    lateinit var displayMetrics:DisplayMetrics
    var value = 0f
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_sdk_version)
        txt_info=findViewById(R.id.txt_info)
    }

    fun getInfo(view: View) {
        displayMetrics = DisplayMetrics()
       windowManager.defaultDisplay.getMetrics(displayMetrics)
        value = resources.displayMetrics.density
        txt_info.text = "Screen Density = $value"
    }
}