小编Key*_*iya的帖子

我正在尝试使用cardview显示与recyclerview的联系，并且出现此错误：

java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法'void android.support.v7.widget.RecyclerView.setLayoutManager（android.support.v7.widget.RecyclerView $ LayoutManager）'

Fragment Parent是BottomNavigationViewTab-我试图显示联系人的地方。

Contact_List_Fragment.java

public class Contact_List_Fragment extends android.support.v4.app.Fragment {

    RecyclerView recyclerView;
    ArrayList<String> contact_names = new ArrayList<>(), mobile_numbers = new ArrayList<>();

    public Contact_List_Fragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View contact_fragment =  inflater.inflate(R.layout.contact_list_fragment, container, false);

        String[] PROJECTION_MAIN = new String[]{
                ContactsContract.Contacts._ID,
                ContactsContract.CommonDataKinds.Phone.NUMBER,
                ContactsContract.Contacts.DISPLAY_NAME
        };

        Cursor cursor = getActivity().getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                PROJECTION_MAIN, null, null, null);

        while (cursor.moveToNext()) {
            String …