Error con ViewPager y RecyclerView

Estoy usando un ViewPager con un RecyclerView dentro del primer fragmento del ViewPager.

Cuando me desplazo de izquierda a derecha, no hay errores. Pero cuando me desplazo de derecha a izquierda (desde el # 2 para el fragmento # 1 del ViewPager), se produce el siguiente error:

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05-10 20:21:07.546 20002-20002/com.graffiti75.android.worldremit E/AndroidRuntime﹕ FATAL EXCEPTION: main Process: com.graffiti75.android.worldremit, PID: 20002 java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v7.widget.RecyclerView$LayoutManager.canScrollHorizontally()' on a null object reference at android.support.v7.widget.RecyclerView.onInterceptTouchEvent(RecyclerView.java:1819) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1960) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049) at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2369) at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1719) at android.app.Activity.dispatchTouchEvent(Activity.java:2742) at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2330) at android.view.View.dispatchPointerEvent(View.java:8666) at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4123) at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3989) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3544) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3597) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3563) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3680) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3571) at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3737) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3544) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3597) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3563) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3571) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3544) at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5807) at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5781) at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5752) at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:5897) at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185) at android.os.MessageQueue.nativePollOnce(Native Method) at android.os.MessageQueue.next(MessageQueue.java:143) at android.os.Looper.loop(Looper.java:122) at android.app.ActivityThread.main(ActivityThread.java:5254) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 05-10 20:21:07.549 550-7690/? W/ActivityManager﹕ Force finishing activity 1 com.graffiti75.android.worldremit/.activity.WalkthroughActivity 

Ese es el error: java.lang.NullPointerException: Intenta invocar el método virtual 'boolean android.support.v7.widget.RecyclerView $ LayoutManager.canScrollHorizontally ()' en una referencia de objeto nulo

El siguiente método es el primer fragmento de mi ViewPager. Cuando comento las líneas donde se llama a RecyclerView, no se producen errores. Pero necesito este RecyclerView para navegar por mis contactos! Así que supongo que esto demuestra que el error ocurre en esas líneas …

 public class ContactListFragment extends Fragment { //-------------------------------------------------- // Constructor //-------------------------------------------------- public static ContactListFragment newInstance() { ContactListFragment fragment = new ContactListFragment(); Bundle args = new Bundle(); fragment.setArguments(args); return fragment; } public ContactListFragment() { // Required empty public constructor } //-------------------------------------------------- // Fragment Life Cycle //-------------------------------------------------- @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment. View v = inflater.inflate(R.layout.fragment_contact_list, container, false); // Get data. List<String> nameList = new ArrayList<String>(); Cursor cursor = getContacts(); while (cursor.moveToNext()) { String name = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME)); nameList.add(name); } // Setup list. RecyclerView recyclerView = (RecyclerView) v.findViewById(R.id.id_recycler_view); recyclerView.setHasFixedSize(true); Activity activity = getActivity(); final LinearLayoutManager layoutManager = new LinearLayoutManager(activity); layoutManager.setOrientation(LinearLayoutManager.VERTICAL); recyclerView.setLayoutManager(layoutManager); recyclerView.setItemAnimator(new DefaultItemAnimator()); recyclerView.setAdapter(new ContactListAdapter(getActivity(), nameList)); return v; } //-------------------------------------------------- // Methods //-------------------------------------------------- private Cursor getContacts() { // Run query. Uri uri = ContactsContract.Contacts.CONTENT_URI; String[] projection = new String[] { ContactsContract.Contacts._ID, ContactsContract.Contacts.DISPLAY_NAME }; String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP + " = '" + ("1") + "'"; String[] selectionArgs = null; //String sortOrder = ContactsContract.Contacts._ID + " COLLATE LOCALIZED ASC"; String sortOrder = ContactsContract.Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC"; return getActivity().managedQuery(uri, projection, selection, selectionArgs, sortOrder); } } 

Aquellas líneas abajo: // Lista de configuración.

Investigué mucho en Google y no pude encontrar una manera de solucionar estos errores.

¿Alguien tiene una suposición?

 public class HackyViewPager extends ViewPager { public HackyViewPager(Context context) { super(context); } public HackyViewPager(Context context, AttributeSet attrs) { super(context, attrs); } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { try { return super.onInterceptTouchEvent(ev); } catch (Throwable t) { t.printStackTrace(); return false; } }}