@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            StartFragment startFragment = new StartFragment();
            getFragmentManager().beginTransaction()
          .replace(R.id.content_frame, startFragment).commit();
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}