gistfile1.txt

   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main_activity);

        mBottomNavigationBar = findViewById(R.id.main_bottom_navigation_menu);

        setupBottomNavigationBar();

        // Listen
        mBottomNavigationBar.setOnTabSelectedListener((position, wasSelected) -> {
            displayFragment(position);

            return true;
        });

        // Style matters
        mBottomNavigationBar.setColored(true);

        // Init
        if (savedInstanceState == null) {
            displayFragment(0);
        }
    }

    private void displayFragment(int position) {
        if (position == mLastBottomNavPosition) {
            return;
        }

        Fragment fragToShow = null;

        switch (position) {
            case 0: // Appointments
                fragToShow = AppointmentFragment.newInstance();
                break;
            case 1: // News
                fragToShow = NewsFragment.newInstance();
                break;
            case 2: // Profile
                fragToShow = ProfileFragment.newInstance();
                break;
        }

        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();

        if (mLastBottomNavPosition != -1) {
            if (mLastBottomNavPosition < position) {
                transaction.setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_left);
            } else {
                transaction.setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right);
            }
        }

        transaction.replace(R.id.main_fragment_container, fragToShow).commit();

        mLastBottomNavPosition = position;
    }