Backstack片段

Question

我有Fragment的问题。

我创建了一个main_activity并在其中添加了一个listFragment。当我点击一个listfragment项时，我打开一个新片段。我想将listfragment添加到backstack，但是当我单击后退按钮时我退出应用程序。这是我点击事件的代码：

  @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    /*    if (null != mListener) {
            // Notify the active callbacks interface (the activity, if the
            // fragment is attached to one) that an item has been selected.
            mListener.onFragmentInteraction(DummyContent.ITEMS.get(position).id);
        }
*/
        jsonitem item = this.listFragment.get(position);



        Fragment newFragment = new descrizione_fragment();
        Bundle bundle = new Bundle();
        bundle.putString("evento_id",item.getTitle().toString());
        newFragment.setArguments(bundle);
        final android.app.FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.content_frame, newFragment);


        transaction.addToBackStack(null);
        transaction.commit();

        //Toast.makeText(getActivity(), item.getTitle() + " Clicked!" , Toast.LENGTH_SHORT).show();
    }