rvCategories = (RecyclerView) view.findViewById(R.id.rv);

    adapter = new CategoryAdapter(getContext(), addCategories(TYPE), TYPE, null);
    GridLayoutManager glm = new GridLayoutManager(getActivity(), 2, GridLayoutManager.HORIZONTAL, false);
    rvCategories.setAdapter(adapter);
    rvCategories.setLayoutManager(glm);
    rvCategories.setLayoutManager(glm);
    rvCategories.setHasFixedSize(true);
    rvCategories.addItemDecoration(**вот тут что?**);

<application
 android:icon="@drawable/ic_launcher"
 android:label="@string/app_name"
 android:name=".MyApp">

 ...
</application>