Android Kotlin - Can't call onNavigationItemSelected method

You can give your NavigationView an ID in your layout file:

<android.support.design.widget.NavigationView
    android:id="@+id/navigationView"
    ... >
</android.support.design.widget.NavigationView>

And then add a listener to it in your UserActivity:

navigationView.setNavigationItemSelectedListener {
    when (it.itemId) {
        R.id.nav_home -> {
            // handle click
            true
        }
        else -> false
    }
}