Animated Drop Marker Kotlin

startDropMarkerAnimation.kt

private fun startDropMarkerAnimation(marker: Marker) {
        val target = marker.position
        val handler = Handler()
        val start = SystemClock.uptimeMillis()
        val proj = mMap!!.projection
        val targetPoint = proj.toScreenLocation(target)
        val duration = (200 + targetPoint.y * 0.6) as Double
        val startPoint = proj.toScreenLocation(marker.position)
        startPoint.y = 0
        val startLatLng = proj.fromScreenLocation(startPoint)
        val interpolator = LinearOutSlowInInterpolator()
        handler.post(object : Runnable {
            override fun run() {
                val elapsed = SystemClock.uptimeMillis() - start
                val t = interpolator.getInterpolation((elapsed.toFloat() / duration).toFloat())
                val lng = t * target.longitude + (1 - t) * startLatLng.longitude
                val lat = t * target.latitude + (1 - t) * startLatLng.latitude
                marker.setPosition(LatLng(lat, lng))
                if (t < 1.0) {
                    // Post again 16ms later == 60 frames per second
                    handler.postDelayed(this, 16)
                }
            }
        })
    }