How to change the title of fragment when press back?

Question

I have 3 fragments, Home, Menu and orders they can be loaded by bottomnavigtioview items and the title shown by it as well once navigate from Home to Orders then if you want to go back to Home From Orders the title still "Orders"

    public boolean onNavigationItemSelected(@NonNull MenuItem item) {

        Fragment fragment;

        switch (item.getItemId()) {
            case R.id.navigation_home:
                toolbar.setTitle(getResources().getString(R.string.title_home));
                fragment = new HomeFragment();
                loadFragment(fragment);
                return true;
            case R.id.navigation_menu:
                toolbar.setTitle(getResources().getString(R.string.fragment_title_menu));
                fragment = new ProductFragment();
                loadFragment(fragment);
                return true;
            case R.id.navigation_orders:
                toolbar.setTitle(getResources().getString(R.string.title_orders));
                fragment = new OrdersFragment();
                loadFragment(fragment);
                return true;
        }
        return false;
    }
};

private void loadFragment(Fragment fragment) {
    // load fragment
   FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
       transaction.replace(R.id.frame_container, fragment);
       transaction.addToBackStack(null);
       transaction.commit();
}

@Override

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    context = this;

     navigation =  findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);


    // attaching bottom sheet behaviour - hide / show on scroll
    CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) navigation.getLayoutParams();
    layoutParams.setBehavior(new BottomNavigationBehavior());

    toolbar.setTitle(getResources().getString(R.string.title_home));
    Fragment f = HomeFragment.newInstance();
    getSupportFragmentManager().beginTransaction()
            .replace(R.id.frame_container, f)
            .commit();
}`

I have Also Tried this but its not working

`

fragmentmanger.addOnBackStackChangedListener -> public void onBackStackChanged() {

        }`

Answer 1

It worked for me when calling it in onResume like this in each fragment:

if(getActivity()!=null) { ((MainActivity)getActivity()).setActionBarTitle (context.getResources().getString(R.string.YOUR_TITLE)); this is the function setActionBarTitle in MainActivity

public void setActionBarTitle(String title) { toolbar.setTitle(title); }