setLayoutManager NullPointException in RecyclerView

Question

I'm trying to receive a list with an array in RecyclerView and get error:

java.lang.NullPointerException: Attempt to invoke virtual method 
'void android.support.v7.widget.RecyclerView.setLayoutManager
(android.support.v7.widget.RecyclerView$LayoutManager)'on a null object reference

RecyclerView widget's

   <android.support.v7.widget.RecyclerView
        android:id="@+id/drawerList"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </android.support.v7.widget.RecyclerView>

I tried to declare LayoutManager to final, but it doesn't help.

Activity code:

public class MainActivity extends ActionBarActivity {

private RecyclerView recyclerView;
private Toolbar toolbar;
private InfAdapter adapter;


@Override
protected void onCreate (Bundle savedInstanceState) {
    super.onCreate (savedInstanceState);
    setContentView (R.layout.activity_main_appbar);

    recyclerView = (RecyclerView) findViewById(R.id.drawerList);

    recyclerView.setLayoutManager(new LinearLayoutManager(this));

    InfAdapter mAdapter = new InfAdapter(this, getData());
    recyclerView.setAdapter(mAdapter);
    recyclerView.setItemAnimator(new DefaultItemAnimator());

    toolbar = (Toolbar) findViewById(R.id.app_bar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayShowHomeEnabled(true);

}

Adapter code:

public class InfAdapter extends RecyclerView.Adapter<InfAdapter.MyViewHolder> {

  private final Context context;
    private  List<Information> data = Collections.emptyList();


    public InfAdapter(Context context, List<Information> data){
        this.data = data;
        this.context = context;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.custom_row, parent, false);
        return new MyViewHolder(v);
    }


    @Override
    public void onBindViewHolder(MyViewHolder  holder, int position) {

        Information current  = data.get(position);
        holder.title.setText(current.title);
        holder.icon.setImageResource(current.iconid);
    }


    @Override
    public int getItemCount() {
        return data.size();
    }

    class MyViewHolder extends RecyclerView.ViewHolder{
    TextView title;
    ImageView icon;

    public MyViewHolder(View itemView) {

        super(itemView);
        title = (TextView) itemView.findViewById(R.id.listText);
        icon = (ImageView) itemView.findViewById(R.id.listIcon);

        }
    }
}

What has possibly gone wrong?

can you post your layout code too....does your layout code have RecyclerView like this ` — Psypher, Feb 17 '15 at 21:11
The LogCat output should provide you with the specific line of code where the null pointer exception is occurring or you can run this in the debugger and put a break point at the setLayoutManger line of code and see which object is null. — faljbour, Feb 18 '15 at 00:08
Provide your entire layout file. This looks like the layout you set for the activity does not contain the id used for the recycler view. — Larry Schiefer, Feb 18 '15 at 00:20

score 43 · Accepted Answer · answered Feb 18 '15 at 21:09

43

As @StenSoft noted in comments the problem was in setContentView (R.layout.activity_main_appbar); because of wrong activity layout content, instead of setContentView (R.layout.activity_main);

answered Feb 18 '15 at 21:09

Ardi

1,811
4
17
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6

Damn this copy paste... -_- – nimi0112 May 25 '18 at 08:26
@nimi0112 ikr! LOL – Francis Saa-Dittoh Apr 17 '20 at 19:29

score 10 · Answer 2 · edited Mar 12 '17 at 18:59

10

In my case this error comes because I did not create RecyclerView in one of my activity .

check your activity layout or fragment layout.

edited Mar 12 '17 at 18:59

thor

21,418
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answered Mar 12 '17 at 18:28

score 0 · Answer 3 · answered Mar 16 '21 at 04:33

I had something similar ,but in kotlin and inside the

RecyclerView.apply {}

code, in the line :

layoutManager = viewManager

eventually I found out it was because I inflated the wrong layout to the fragment, in the line:

return inflater.inflate(R.layout.main_fragment, container, false)

score -1 · Answer 4 · answered Mar 14 '23 at 11:57

-1

seriously, for the record, check the recicler view id

answered Mar 14 '23 at 11:57

Fiendel

1

idea given by https://stackoverflow.com/a/42751385/21396068 – Fiendel Mar 14 '23 at 11:59
As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Mar 19 '23 at 08:09
This does not provide an answer to the question. Once you have sufficient [reputation](https://stackoverflow.com/help/whats-reputation) you will be able to [comment on any post](https://stackoverflow.com/help/privileges/comment); instead, [provide answers that don't require clarification from the asker](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead). - [From Review](/review/late-answers/34032216) – Sergei Kozelko Mar 21 '23 at 01:41

setLayoutManager NullPointException in RecyclerView

4 Answers4

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