在Fragment中使用RecyclerView

public class Fragment1 extends Fragment {

	private RecyclerView mRecyclerView;
	private GalleryAdapter mAdapter;
	private List<Integer> mDatas = new ArrayList<Integer>(Arrays.asList(
			R.drawable.head1, R.drawable.head2, R.drawable.head3,
			R.drawable.head4, R.drawable.head5, R.drawable.head6,
			R.drawable.head7, R.drawable.head8));

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View rootView = inflater.inflate(R.layout.view1, container, false);
		mRecyclerView = (RecyclerView) rootView.findViewById(R.id.id_recyclerview);
		mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
		mAdapter = new GalleryAdapter(getActivity(), mDatas);
		mRecyclerView.setAdapter(mAdapter);
		return rootView;
	}
}

报异常：

java.lang.NullPointerException

at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:1310)

at android.view.View.measure(View.java:16525)

at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)

at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)