我有一个底部导航栏与4节片段附加。在每个片段都有一些东西，通过点击，我将到其他片段，这不是节片段。我想显示底部导航栏只在节片段。那么如何隐藏底部导航栏在其他片段？
下面是我的底部导航条形码：

package com.fahim69.bazaarapp.FragmentHolder;
public class ShowFragment extends AppCompatActivity {
BottomNavigationView bottomnav;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_show_fragment);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
    WindowManager.LayoutParams.FLAG_FULLSCREEN);
    bottomnav = findViewById(R.id.nav_bar);
    replacefragment(new HomeFragment());
    bottomnav.setOnItemSelectedListener(new NavigationBarView.OnItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            Fragment fragment = null;
            switch (item.getItemId()) {
                case R.id.nav_home:
                    replacefragment(new HomeFragment());
                    break;
                case R.id.nav_category:
                    replacefragment(new CategoryFragment());
                    break;
                case R.id.nav_cart:
                    replacefragment(new CartFragment());
                    break;
                case R.id.nav_profile:
                    replacefragment(new ProfileFragment());
                    break;
            }

            return true;
        }
    });
    

}

private void replacefragment(Fragment fragment) {
    FragmentManager fragmentManager = getSupportFragmentManager();
    //fragmentManager.popBackStack();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.replace(R.id.fragment_container, fragment);
    fragmentTransaction.addToBackStack(null);
    fragmentTransaction.commit();
}

@Override
public void onBackPressed() {
    FragmentManager fm = getSupportFragmentManager();
    if(fm.getBackStackEntryCount()>0)fm.popBackStack();
    else{
        super.onBackPressed();
    }

}

}