Change drawer icon back to back arrow

Question

I'm using the new DrawerLayout to have side navigation. I'm using the drawer icon (the 'hamburger') like this:

@Override
protected void onStart() {
    super.onStart();

    mDrawerLayout = (DrawerLayout) findViewById(R.id.activity_main_drawerlayout);
    mDrawerToggle = new ActionBarDrawerToggle(
            this, 
            mDrawerLayout, 
            R.drawable.ic_navigation_drawer, 
            R.string.app_name, 
            R.string.app_name);
    mDrawerLayout.setDrawerListener(mDrawerToggle);

    getActionBar().setDisplayHomeAsUpEnabled(true);
    getActionBar().setHomeButtonEnabled(true);
}

However, when I add a Fragment to the backstack, I want to display the back arrow again, so the user can navigate back to "home", and only then open the app drawer.

How can I reset the drawer icon to the back icon?
The arrow I want:

Answer 1

To disable and hide the DrawerToggle "Hamburger", just call

mDrawerToggle.setDrawerIndicatorEnabled(false);

Answer 2

I created an interface for the hosting activity to update the view state of the hamburger menu. For top level fragments I set the toggle to true and for fragments for which I want to display the up < arrow I set the toggle to false.

public class SomeFragment extends Fragment {

    public interface OnFragmentInteractionListener {
        public void showDrawerToggle(boolean showDrawerToggle);
    }

    private OnFragmentInteractionListener mListener;

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            this.mListener = (OnFragmentInteractionListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString() + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onResume() {
        super.onResume();
        mListener.showDrawerToggle(false);
    }
}

Then in my Activity ...

public class MainActivity extends Activity implements SomeFragment.OnFragmentInteractionListener {

    private ActionBarDrawerToggle mDrawerToggle;

    public void showDrawerToggle(boolean showDrawerIndicator) {
        mDrawerToggle.setDrawerIndicatorEnabled(showDrawerIndicator);
    }

}