replacing nested fragments

replace.java

public void replaceFragment(DialogFragment replacementFragment, String tag, String pageTitle) {
    FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
    transaction.setCustomAnimations(R.anim.slide_left_from_right, android.R.anim.fade_out, android.R.anim.fade_in,
 R.anim.slide_out_right_from_left);
    transaction.replace(R.id.fragment_content, replacementFragment, tag);
    transaction.addToBackStack(tag);
    transaction.commit();
    if (!TextUtils.isEmpty(pageTitle)) {
       mToolbar.setTitle(pageTitle);
  mToolbar.setNavigationIcon(R.drawable.ic_nav_back_green_selector);
    }
 }