Actionbar Backbutton

public class ActionBarSettings {
    private static DrawerLayout drawerLayout;
    private static ActionBarDrawerToggle drawerToggle;
    private static Toolbar toolbar;
    public static void setValues(DrawerLayout layout, ActionBarDrawerToggle toggle, Toolbar bar) {
        drawerLayout = layout;
        drawerToggle = toggle;
        toolbar = bar;
    }
    public static void enableUpButton(final AppCompatActivity activity) {
        if (drawerLayout != null && drawerLayout != null && toolbar != null) {
            drawerToggle.setDrawerIndicatorEnabled(false);
            drawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                activity.onBackPressed();
                }
            });
            Toolbar t = toolbar;
            t.setNavigationIcon(activity.getDrawerToggleDelegate().getThemeUpIndicator());
            drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
        }
    }
    public static void disableUpButton(final AppCompatActivity activity) {
        drawerToggle.setDrawerIndicatorEnabled(true);
        Toolbar t = toolbar;
        drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
    }
}

public class MyFragment extends Fragment {
@Override
    public void onResume() {
        super.onResume();
        ActionBarSettings.enableUpButton((AppCompatActivity) getActivity());
    }




    @Override
    public void onDestroyView() {
        ActionBarSettings.disableUpButton((AppCompatActivity) getActivity());
        super.onDestroyView();
    }
}