To use these methods in other activities, extend the Actionbar_methods class.
Something like :
public class FirstActivity extends Actionbar_methods {
//Add other methods here.
//You'll be able to use setupActionBar() method here.
@Override
protected void onCreate(Bundle savedInstanceState) {
setContentView(R.layout.first_activity);
super.onCreate(savedInstanceState);
setupActionBar();
}
}