How to use

finish

method

in

com.nguyenhoanglam.sample.MainActivity

  @Override
  public void onBackPressed() {
    FragmentManager fm = getSupportFragmentManager();
    Fragment fragment = fm.findFragmentById(R.id.fragment_container);
    if (fragment == null) {
      finish();
    } else {
      fm.beginTransaction().remove(fragment).commitAllowingStateLoss();
    }
  }
}