How to get height of status bar

MainActivity.kt

class MainActivity : ActivityCompat {

    private lateinit var bordersListener: ViewTreeObserver.OnGlobalLayoutListener
    private var statusBarHeight = 0

    override fun onCreate(savedInstanceState: Bundle?) {

        val decorView = window.decorView
        bordersListener = ViewTreeObserver.OnGlobalLayoutListener {
            val r = Rect()
            decorView.getWindowVisibleDisplayFrame(r)
            val topOffset = r.top

            if (topOffset > 0) {
                statusBarHeight = topOffset
                removeBordersListener()
            }
        }

        decorView.viewTreeObserver.addOnGlobalLayoutListener(bordersListener)
    }

    private fun removeBordersListener() {
        window.decorView.viewTreeObserver.removeOnGlobalLayoutListener(bordersListener)
    }
}