package test import android.app.Activity import android.view.View import android.widget.* import org.my.cool.MyButton import kotlinx.android.synthetic.main.layout.* class R { class id { companion object { const val login = 5 } } } class MyActivity(): Activity() { val buttonWidget = MyButton(this) override fun findViewById(id: Int): T? { return when (id) { R.id.login -> buttonWidget as T else -> null } } } fun box(): String { return "OK" }