Resuming a previous fragment onBackPressed()?

Change

@Override
public void onBackPressed() 
{
   getFragmentManager().popBackStack();
   super.onBackPressed();
}

to

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

and

fragmentManager.beginTransaction().replace(R.id.home_container, frag).commit();

to

fragmentManager.beginTransaction().replace(R.id.home_container, frag).addToBackStack(null).commit();

Add your fragment to back stack using addToBackStack(null) like..

fragmentManager.beginTransaction().replace(R.id.home_container, frag).addToBackStack(null).commit();