button not change on back button press in BottomNavigationView

Question

i use three fragment in dashbordActivity on bottom navigation bar. On back button press previous fragment view properly but bottom navigation button not changing.

in first image home fragment is already selected after i select profile from bottom navigation and press backbutton. fragment changes but bottom navigation item does not change.

this is my bottom navigation view .....

  private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
        = new BottomNavigationView.OnNavigationItemSelectedListener() {
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId()) {
            case R.id.navigation_home:
                setTitle("Home");
                fragment = new FirstFragment();
                loadFragment(fragment);
                return true;
            case R.id.navigation_favorite:

                setTitle("favourite");
                fragment = new MyFavoriteAdsFragment();
                loadFragment(fragment);
                return true;
            case R.id.navigation_profile:

                setTitle("Profile");
                fragment = new ProfileFragment();
                loadFragment(fragment);
                return true;
            case R.id.navigation_myads:
                setTitle("Chat");
                fragment = new MyAdsFragment();
                loadFragment(fragment);
                return true;
            case R.id.navigation_chat:
                //   mTextMessage.setText(R.string.title_chat);
                setTitle("Chat");
                fragment = new TabFragmentChatUserList();
                loadFragment(fragment);
              /* Intent i=new Intent(getApplicationContext(),Chat.class);
               startActivity(i);*/
                return true;
        }
        return false;
    }
};


  private void loadFragment(Fragment fragment) {
    // load fragment
     transaction = getSupportFragmentManager().beginTransaction();
    transaction.replace(R.id.frame_container, fragment);
    transaction.addToBackStack("TAG");
    transaction.commit();
  /*  fragmentManager.beginTransaction().replace(R.id.home_container, frag).addToBackStack(null).commit();*/
}

ob back press i tryed...

   @Override
  public void onBackPressed()
  {

 // if your using fragment then you can do this way
        int fragments 
  =getSupportFragmentManager().getBackStackEntryCount();
        if (fragments == 1) {
            new AlertDialog.Builder(this)
                    .setMessage("Are you sure you want to exit?")
                    .setCancelable(false)
                    .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            finish();
                        }
                    })
                    .setNegativeButton("No", null)
                    .show();


        } else {
            if (getFragmentManager().getBackStackEntryCount() > 1) {
                getFragmentManager().popBackStack();
                if(navigation.getSelectedItemId () != R.id.navigation_favorite)
                {
                    navigation.setSelectedItemId(R.id.navigation_favorite);
                }
                else if(navigation.getSelectedItemId () != R.id.navigation_chat)
                {
                    navigation.setSelectedItemId(R.id.navigation_chat);
                }
                else if(navigation.getSelectedItemId () != R.id.navigation_profile)
                {
                    navigation.setSelectedItemId(R.id.navigation_profile);
                }
                else
                {
                    super.onBackPressed();
                }

            } else {
                super.onBackPressed();
            }
        }

Answer 1

You can customize your onBackPressed in this way:

 @Override
    public void onBackPressed() {
    // if your using fragment then you can do this way
    int fragments
            = getSupportFragmentManager().getBackStackEntryCount();
    if (fragments == 1) {
        new AlertDialog.Builder(this)
                .setMessage("Are you sure you want to exit?")
                .setCancelable(false)
                .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        finish();
                    }
                })
                .setNegativeButton("No", null)
                .show();


    } else {
        if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
            getSupportFragmentManager().popBackStack();
            Fragment selectedFragment = null;
            List<Fragment> fragments = getSupportFragmentManager.getFragments();
            for (Fragment fragment : fragments) {
                if (fragment != null && fragment.isVisible()) {
                    selectedFragment = fragment;
                    break;
                }
            }
            if (selectedFragment instanceof yourFirstFragment) {
                navigation.setSelectedItemId(R.id.your_first_item);
            } if (selectedFragment instanceof yourSecondFragment) {
                navigation.setSelectedItemId(R.id.your_second_item);
            } if (selectedFragment instanceof yourThirdFragment) {
                navigation.setSelectedItemId(R.id.your_third_item);
            } else {
                super.onBackPressed();
            }

        } else {
            super.onBackPressed();
        }
    }

Answer 2

You need to check your backstack and add listener to your fragment manager, after that based on your fragment you need to set particular button check based on your fragment.

fragmentManager.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
        @Override
        public void onBackStackChanged() {
            // If the stack decreases it means I clicked the back button
            if( fragmentManager.getBackStackEntryCount() <= count){
                //check your position based on selected fragment and set it accordingly.
                navigation.getMenu().getItem(your_pos).setChecked(true);
        }
    }
});