Unresolved reference: imageSwitcher - kotlin

Question

I'm trying to create an image switcher for a battery animation. using kotlin support is there anything I'm missing?
import android.content.Intent
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.os.Handler
import android.view.View
import android.widget.ImageSwitcher
import java.util.*
class SplashScreen : AppCompatActivity() {
private val splashTimeOut = 6000L
private val chargeAnimation = arrayOf(
R.drawable.charge_1,
R.drawable.charge2,
R.drawable.charge_3,
R.drawable.charge_4)
private var index = 0
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_splash_screen)
window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION or
View.SYSTEM_UI_FLAG_LAYOUT_STABLE or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION or
View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN or View.SYSTEM_UI_FLAG_FULLSCREEN or
View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
val t = Timer()
//Set the schedule function and rate
t.scheduleAtFixedRate(object : TimerTask() {
override fun run() {
//Called each time when 1000 milliseconds (1 second) (the period parameter)
// If index reaches maximum reset it
if (index + 1 < chargeAnimation.size) index + 1 else 0
runOnUiThread { ***imageSwitcher***.setImageResource(chargeAnimation[index]) }
}
}, 500, 1000)
Handler().postDelayed(Runnable{
kotlin.run{
val intent = Intent(this, RegisterScreen::class.java)
startActivity(intent)
finish()
}
}, splashTimeOut)}}