不启用活动后的奇怪活动片段行为

Question

我从活动中膨胀了一个片段。如果未启用开发人员设置中的活动选项，则片段不会加载应加载的列表。

片段代码是：

public class WidgetListFragment extends ListFragment {

private DummyAdapter mAdapter;
private LinearLayout mButtonBar;
private DummyCardHost mAppWidgetHost;

private static final List<MyListMenuItem> MY_LIST_MENU_ITEMS = new ArrayList<MyListMenuItem>() {{
    add(MyListMenuItem.ADD_WIDGET_STREAM);
}};

/**
 * Loader for favorite cards.
 */
private final LoaderManager.LoaderCallbacks<List<Card>> mCardsLoader = new LoaderManager.LoaderCallbacks<List<Card>>() {
    @Override
    public Loader<List<Card>> onCreateLoader(int id, Bundle args) {
        return new MyWidgetsLoader(getActivity());
    }

    @Override
    public void onLoadFinished(Loader<List<Card>> loader, List<Card> cards) {
        updateAdapter(cards);
    }

    @Override
    public void onLoaderReset(Loader<List<Card>> loader) {
    }
};

public WidgetListFragment() {
    super();
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mAppWidgetHost = new DummyCardHost(getActivity(), WidgetHostIds.MY_WIDGETS);
    mAppWidgetHost.startListening();
}

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_layout, container, false);
    return view;
}

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    mButtonBar = new LinearLayout(getActivity());
    mButtonBar.setOrientation(LinearLayout.HORIZONTAL);
    mButtonBar.setLayoutParams(new AbsListView.LayoutParams(AbsListView.LayoutParams.MATCH_PARENT,
            AbsListView.LayoutParams.WRAP_CONTENT));
    EditableListView listView = (EditableListView) getListView();
    listView.addFooterView(mButtonBar);

    listView.setOnEditModeListener(this);
    listView.setEditableAdapter(null);
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    getLoaderManager().restartLoader(LOADER_ID, null, mCardsLoader);

}

@Override
public void onDestroy() {
    super.onDestroy();
    mAppWidgetHost.stopListening();
    getLoaderManager().destroyLoader(LOADER_ID);
}

private void updateAdapter(List<Card> cards) {
    if (mAdapter != null) mAdapter.clear();
    mAdapter = new CardListAdapter(getListView(), this, mAppWidgetHost,
            cards, new Space(SpaceConstants.MY_WIDGETS_SPACE_ID));
    mAdapter.setMyListMenuItems(mButtonBar, MY_LIST_MENU_ITEMS, true);
    ((EditableListView) getListView()).setEditableAdapter(mAdapter);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (mAdapter != null) {
        mAdapter.onActivityResult(requestCode, resultCode, data);
    }
}

活动是：

public class MyWidgetsActivity extends FragmentActivity {

private WidgetListFragment mFragment;

public MyWidgetsActivity() {
    super();
    DependencyInjectionService.inject(this);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_my_widgets);
    mFragment = (WidgetListFragment) getSupportFragmentManager().findFragmentById(R.id.widget_fragment);

    }
}

为什么杀死之前的活动的任何想法都会使片段过时？