avoid fragment recreation BottomNavigationView - android-fragments

Question

i want to avoid fragment recreation by using BottomNavigationView
i read about that FragmentTransaction.replace is the problem and changing to add would help, but that didn't work for me..
maybe you can see here where i'm wrong
this is my Host Activity which hosting 3 fragments with BottomNavigationView
'''
class Host : AppCompatActivity() {
var fragment: Fragment? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_host)
//for hide the actionBar (contains Fragment name) on top of the screen
val actionBar = supportActionBar
actionBar?.hide()
val navController = Navigation.findNavController(this, R.id.nav_host_fragment)
val navView = findViewById<BottomNavigationView>(R.id.nav_view)
navView?.setupWithNavController(navController)
NavigationUI.setupWithNavController(navView, navController)
mAdapter = NfcAdapter.getDefaultAdapter(this)
fragmentStayAlive()
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
for (fragment in supportFragmentManager.fragments) {
fragment.onActivityResult(requestCode, resultCode, data)
}
}
fun ByteArray.toHexString() = joinToString("") { "%02x".format(it) }
private fun fragmentStayAlive(){
val fragment1: Fragment = LobbyFragment()
val fragment2: Fragment = GameSessionFragment()
val fragment3: Fragment = UserStatusFragment()
val fm: FragmentManager = supportFragmentManager
var active = fragment1
fm.beginTransaction().add(R.id.nav_host_fragment, fragment3, "UserStatusFragment").hide(
fragment3
).commit();
fm.beginTransaction().add(R.id.nav_host_fragment, fragment2, "GameSessionFragment").hide(
fragment2
).commit();
fm.beginTransaction().add(R.id.nav_host_fragment, fragment1, "LobbyFragment").commit();
val mOnNavigationItemSelectedListener: BottomNavigationView.OnNavigationItemSelectedListener =
object : BottomNavigationView.OnNavigationItemSelectedListener {
override fun onNavigationItemSelected(item: MenuItem): Boolean {
when (item.getItemId()) {
R.id.lobbyFragment -> {
fm.beginTransaction().hide(active).show(fragment1).commit()
active = fragment1
return true
}
R.id.gameSessionFragment -> {
fm.beginTransaction().hide(active).show(fragment2).commit()
active = fragment2
return true
}
R.id.userStatusFragment -> {
fm.beginTransaction().hide(active).show(fragment3).commit()
active = fragment3
return true
}
}
replaceFragment(active, null, true, true)
return false
}
}
}
fun replaceFragment(
fragment: Fragment,
#Nullable bundle: Bundle?,
popBackStack: Boolean,
findInStack: Boolean
) {
val fm = supportFragmentManager
val ft: FragmentTransaction = fm.beginTransaction()
val tag = fragment.javaClass.name
val parentFragment: Fragment?
parentFragment = if (findInStack && fm.findFragmentByTag(tag) != null) {
fm.findFragmentByTag(tag)
} else {
fragment
}
// if user passes the #bundle in not null, then can be added to the fragment
if (bundle != null) {
parentFragment!!.arguments = bundle
} else {
parentFragment!!.arguments = null
}
// this is for the very first fragment not to be added into the back stack.
if (popBackStack) {
fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE)
} else {
ft.addToBackStack(parentFragment.javaClass.name + "")
}
ft.add(R.id.nav_view, parentFragment, tag)
ft.commit()
fm.executePendingTransactions()
}
'''
thanks for all the helpers!