Android fragments overlapping after screen rotation

Question

This app is a learning exercise for me using fragments, among other things. It has a single activity that manages some different fragments. The first is a ListFragment (A), which shows when the app starts and loads list items from a cursor. Clicking a list item notifies the activity to replace the ListFragment with a DetailFragment (B) for that item. If while looking at (B) I rotate the screen, I see (B) on top of (A), like this:

http://postimage.org/image/uhy016ds7/

My best guess is it has to do with Android destroying and re-creating the activity on a configuration change. I am wondering what is the cleanest solution for this problem. Some code snippets follow, let me know if there's something else I should post.

res/layout/home.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/fragment_container"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <fragment
        android:id="@+id/fragment_place_list"
        android:name="com.simbiosys.apps.foodfast.ui.PlaceListFragment"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
    </fragment>
</FrameLayout>

MyActivity.onCreate

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.home);

    placeListFragment = (PlaceListFragment) getSupportFragmentManager().findFragmentById(
            R.id.fragment_place_list);

}

MyActivity.showDetailPane

public void showDetailPane(String id, String reference) {
    placeDetailFragment = PlaceDetailFragment.newInstance(id, reference);
    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction ft = fragmentManager.beginTransaction();
    ft.addToBackStack(null);
    ft.hide(placeListFragment);
    ft.replace(R.id.fragment_container, placeDetailFragment);
    ft.show(placeDetailFragment);
    ft.commit();
}

Answer 1

As per Android dev page, in Activity's onCreate method you should check if the savedInstanceState is null before adding the fragment to the activity. Code snippet of onCreate method of Activity from this page states that.

// However, if we're being restored from a previous state,
// then we don't need to do anything and should return or else
// we could end up with overlapping fragments.
if (savedInstanceState != null) {
     return;
}