Good backstack

Backstack.java

public class MainActivity extends Activity {
  private static final String BACK_STACK_ROOT_TAG = "root_fragment";
  
  public void onTabSelected(int position) {
    // Pop off everything up to and including the current tab
    FragmentManager fragmentManager = getSupportFragmentManager();
    fragmentManager.popBackStack(BACK_STACK_ROOT_TAG, FragmentManager.POP_BACK_STACK_INCLUSIVE);
  
    // Add the new tab fragment
    fragmentManager.beginTransaction()
        .replace(R.id.container, TabFragment.newInstance())
        .addToBackStack(BACK_STACK_ROOT_TAG)
        .commit();
    }
    
    /**
     * Add a fragment on top of the current tab
     */
    public void addFragmentOnTop(Fragment fragment) {
        getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.container, fragment)
                .addToBackStack(null)
                .commit();
    }
}