Fragment z listView.ListView się nie wyświetla.

O to moje layout-y:

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:id="@+id/simplefragment"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

</FrameLayout>

timeline.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_weight="1"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:textSize="18dp"
        android:id="@+id/timelineTextView"
        android:gravity="left"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/timeTextView"
        android:textSize="16dp"
        android:gravity="center"
        />
</LinearLayout>

timetable_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <View
        android:layout_width="2dp"
        android:layout_height="fill_parent"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:background="@color/grey"/>
    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@android:id/list"
        />

</LinearLayout>

I kod javy :

public class MainActivity extends FragmentActivity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
      /*  FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        TimeTableFragment timeTableFragment = new TimeTableFragment();
        fragmentTransaction.add(R.id.simplefragment,timeTableFragment);
        fragmentTransaction.commit();*/
        FragmentManager fragManager = getSupportFragmentManager();

        Fragment theFragment = fragManager.findFragmentById(R.id.simplefragment);
        if (theFragment == null) {
            theFragment = new TimeTableFragment();
            fragManager.beginTransaction()
                    .add(R.id.simplefragment, theFragment)
                    .commit();

        }
    }
}

public class TimeLineAdapter extends BaseAdapter {
    private List<Example> text;
    private Context context;
    private LayoutInflater inflater = null;

    public TimeLineAdapter( Context context,List<Example> text) {
        this.text = text;
        this.context = context;
        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return text.size();
    }

    @Override
    public Object getItem(int position) {
        return text.get(position);
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView != null) {
            holder = (ViewHolder) convertView.getTag();
        } else {
            convertView = inflater.inflate(R.layout.timeline, parent, false);
            holder = new ViewHolder(convertView);
            convertView.setTag(holder);
        }
        Example ex = (Example) getItem(position);
        holder.timelineTextView.setText(ex.getTimelineText());
        holder.timeTextView.setText(ex.getTime());

        return convertView;
    }

    static class ViewHolder {
        @Bind(R.id.timelineTextView)
        TextView timelineTextView;

        @Bind(R.id.timeTextView)
        TextView timeTextView;

        public ViewHolder(View convertView) {
            ButterKnife.bind(this, convertView);
        }
    }
}

public class TimeTableFragment extends ListFragment {


    ListView timeTableListView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View fragment = inflater.inflate(R.layout.timetable_fragment, container, false);
        timeTableListView = (ListView) fragment.findViewById(android.R.id.list);
        ArrayList<Example> list = new ArrayList<Example>();
        list.add(new Example("Hiszpanski", "15min"));
        TimeLineAdapter timeLineAdapter = new TimeLineAdapter(getActivity(), list);
        timeTableListView.setAdapter(timeLineAdapter);
        return fragment;
    }
}

I mój problem jest taki, że listView umieszczone we fragmencie się nie wyświetla. Jakaś pomoc dlaczego tak się dzieje?

Z góry dzięki za odpowiedzi!