class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(R.layout.main_activity)

        var selRegion: Long = 2L
        supportFragmentManager.beginTransaction().replace(
            R.id.fragmentContainer,
            CodeRegionFragment.newInstance(selRegion)
        ).commit()
        regionBottomNavigation.setOnNavigationItemSelectedListener { item ->
            when (item.itemId) {
                R.id.navigation_ru -> {
                    selRegion = 1L
                }
                R.id.navigation_eu -> {
                    selRegion = 3L
                }
                R.id.navigation_ua -> {
                    selRegion = 2L
                }
            }
            supportFragmentManager.beginTransaction().replace(
                R.id.fragmentContainer,
                CodeRegionFragment.newInstance(selRegion)
            ).commit()
            true
        }
    }
}