Use UBS for

override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
getOmikujiButton.setOnClickListener {
Log.v("MainActivity", "Button Clilcked")
// Code here executes on main thread after user presses button
}
}


getOmikujiButton.setOnClickListener {
val results = arrayOf("大吉","吉","中吉","小吉","凶")
val n = Random().nextInt(results.count())
resultTextView.text = results.get(n)
// Code here executes on main thread after user presses button
}
若干抵抗が少なくなってきました。

分岐処理
getOmikujiButton.setOnClickListener {
val results = arrayOf("大吉","吉","中吉","小吉","凶")
val n = Random().nextInt(results.count())
if(n == 0){
resultTextView.setTextColor(Color.RED)
} else{
resultTextView.setTextColor(Color.parseColor("#808080"))
}
resultTextView.text = results.get(n)
// Code here executes on main thread after user presses button
}

OK、では応用してみましょう。