FragmentTransaction without destroying.

FragmentTransactionSansDestroy.kt

val MAP_FRAG_TAG = "mapFragTag"
val LIST_FRAG_TAG = "listFragTag"
    
fun manageFragmentTransaction(selectedFrag: String) {
    when (selectedFrag) {
        MAP_FRAG_TAG -> {
            if (fragmentManager?.findFragmentByTag(MAP_FRAG_TAG) != null) {
                //if the fragment exists, show it.
                fragmentManager?.beginTransaction()?.show(fragmentManager?.findFragmentByTag(MAP_FRAG_TAG))?.commit();
            } else {
                //if the fragment does not exist, add it to fragment manager.
                fragmentManager?.beginTransaction()?.add(R.id.container, MapFragment(), MAP_FRAG_TAG)?.commit();
            }
            if (fragmentManager?.findFragmentByTag(LIST_FRAG_TAG) != null) {
                //if the other fragment is visible, hide it.
                fragmentManager?.beginTransaction()?.hide(fragmentManager?.findFragmentByTag(LIST_FRAG_TAG))?.commit();
            }
        }
        LIST_FRAG_TAG -> {
            if (fragmentManager?.findFragmentByTag(LIST_FRAG_TAG) != null) {
                //if the fragment exists, show it.
                fragmentManager?.beginTransaction()?.show(fragmentManager?.findFragmentByTag(LIST_FRAG_TAG))?.commit();
            } else {
                //if the fragment does not exist, add it to fragment manager.
                fragmentManager?.beginTransaction()?.add(R.id.container, ListFragment(), LIST_FRAG_TAG)?.commit();
            }
            if (fragmentManager?.findFragmentByTag(MAP_FRAG_TAG) != null) {
               //if the other fragment is visible, hide it.
               fragmentManager?.beginTransaction()?.hide(fragmentManager?.findFragmentByTag(MAP_FRAG_TAG))?.commit();
            }
        }
    }
}