BottomNavigationView on fragment

Question

i use Bottom Navigation View and on a fragment its not work fine the problem is there is no transition its only display the first selected

navigationView.setSelectedItemId(R.id.message_menu_Friend);

my code

public class MessageFragment extends Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView =inflater.inflate(R.layout.fragment_message, container, false);

    BottomNavigationView navigationView = rootView.findViewById(R.id.top_navigation_bar);
    navigationView.setOnNavigationItemSelectedListener(topNav);
    navigationView.setSelectedItemId(R.id.message_menu_Friend);
    getChildFragmentManager().beginTransaction().replace(R.id.hostFragment_M,new FriendFragment()).commit();
    // Inflate the layout for this fragment

    return inflater.inflate(R.layout.fragment_message, container, false);
}


private BottomNavigationView.OnNavigationItemSelectedListener topNav = new BottomNavigationView.OnNavigationItemSelectedListener() {
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        Fragment selectedItem = null;
        switch (item.getItemId()) {
            case R.id.message_menu_message:
                selectedItem = new MessagesFragment();
                break;
            case R.id.message_menu_Friend:
                selectedItem = new FriendFragment();
                break;

        }
        assert selectedItem != null;
        getChildFragmentManager().beginTransaction().replace(R.id.hostFragment_M,selectedItem).commit();
        return  true ;
    }
};}

Xml file

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".MessageFragment">



<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">


<FrameLayout android:layout_marginTop="112dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/hostFragment_M">

</FrameLayout>

<EditText
    android:id="@+id/editTextTextPersonSearch"
    android:layout_width="match_parent"
    android:layout_height="56dp"
    android:background="@color/White"
    android:backgroundTint="@color/White"
    android:drawableEnd="@drawable/ic_baseline_search_24"
    android:drawablePadding="8dp"
    android:ems="10"
    android:hint="@string/search"
    android:inputType="textPersonName"
    android:paddingStart="15dp"
    android:paddingEnd="15dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<com.google.android.material.bottomnavigation.BottomNavigationView
    android:id="@+id/top_navigation_bar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/White"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/editTextTextPersonSearch"
    app:menu="@menu/message_menu"
    />
  </androidx.constraintlayout.widget.ConstraintLayout>
</FrameLayout>

how can i make it display the fragment when i click on the bottom navigation

Answer 1

Remove the line navigationView.setSelectedItemId(R.id.message_menu_Friend);, and also change getChildFragmentManager() to getSupportFragmentManager(). Also, in the onCreate method, just return rootView instead of inflating again.