@Override
 public void onBackStackChanged() {
   FragmentManager fragMan = getFragmentManager();
   if (mBackStackLevel != null && fragMan.getBackStackEntryCount() == mBackStackLevel) {
     fragMan.removeOnBackStackChangedListener(this);
     switchState(BackupCodeState.STATE_DISPLAY, true);
     mBackStackLevel = null;
   }
 }
 private void popBackStackNoAction() {
   FragmentManager fragMan = getFragmentManager();
   fragMan.removeOnBackStackChangedListener(this);
   fragMan.popBackStackImmediate(BACK_STACK_INPUT, FragmentManager.POP_BACK_STACK_INCLUSIVE);
   mBackStackLevel = null;
 }