CODEWITHSUNDEEP
javaandroidnullpointerexception
Sander bakker
Sander bakker

Reputation: 505

RecyclerView Nullpointer exception

I have this NullPointer exeption when I launch my RecyclerView fragment but I can't seem to find why it isn't stored inside my variable.

This is my complete code: 

public class LocationFragment extends Fragment {
    FragmentNameFactory nameFactory = new FragmentNameFactory();
    List<LocationData> locationData = new ArrayList<>();
    LocationRecyclerAdapter locationRecyclerAdapter = new LocationRecyclerAdapter(locationData);
    public LocationFragment(){
        //Fragment needs a constructor, can be empty
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        ((MainActivity) getActivity()).setFragmentName(nameFactory.getNameNL(6));
        View view = inflater.inflate(R.layout.flocation, container, false);
        locationData.add(new LocationData("a", "a", "a", "b", 4.55555, 3.39023, "e"));
        RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.locationRecyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setAdapter(locationRecyclerAdapter);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
        recyclerView.setLayoutManager(linearLayoutManager);
        locationRecyclerAdapter.notifyDataSetChanged();
        return view;
    }
    @Override
    public void onViewCreated(View view, Bundle savedInstance){
        super.onViewCreated(view, savedInstance);

    }
    @Override
    public void onActivityCreated(Bundle savedInstance){
        super.onActivityCreated(savedInstance);
    }
}

flocationRecycle.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <android.support.v7.widget.RecyclerView
            android:id="@+id/locationRecyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
        </android.support.v7.widget.RecyclerView>
    </FrameLayout>
</RelativeLayout>

LocationRecyclerAdapter:

public class LocationRecyclerAdapter extends RecyclerView.Adapter<LocationRecyclerAdapter.LocationViewHolder> {
    List<LocationData> locationDataList;
    public class LocationViewHolder extends RecyclerView.ViewHolder {
        public CardView cardView;
        public TextView textViewName;
        public LocationViewHolder(View view) {
            super(view);
            cardView = (CardView) view.findViewById(R.id.card);
            textViewName = (TextView) view.findViewById(R.id.text_view_names);
        }
    }
    public LocationRecyclerAdapter(List<LocationData> locationsDataList){
        this.locationDataList = locationsDataList;
    }
    @Override
    public LocationViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.flocation, parent, false);
        LocationViewHolder locationViewHolder = new LocationViewHolder(view);
        return locationViewHolder;
    }

    @Override
    public void onBindViewHolder(LocationViewHolder holder, int position) {
        holder.textViewName.setText(locationDataList.get(position).getName());
    }

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

flocation.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="120dp">
    <android.support.v7.widget.CardView
        android:id="@+id/card"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        android:layout_marginTop="10dp">
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="102dp">
            <TextView
                android:id="@+id/text_view_names"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentStart="true"
                android:layout_alignParentTop="true"
                android:layout_marginLeft="10dp"
                android:layout_marginTop="10dp"></TextView>
        </RelativeLayout>
    </android.support.v7.widget.CardView>

</RelativeLayout>

The code crashes on this line: recyclerView.setHasFixedSize(true); with a nullpointer like I said above but I can't find why recyclerView is empty

Upvotes: 2

Views: 112

Answers (5)

AndroidStorm
AndroidStorm

Reputation: 869

I was reviewing your code and I found that you inflated the wrong xml file. See that flocationRecycle.xml is the correct one that has to be.

This is your onCreate implementation:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
    ((MainActivity) getActivity()).setFragmentName(nameFactory.getNameNL(6));
    View view = inflater.inflate(R.layout.flocation, container, false);
    locationData.add(new LocationData("a", "a", "a", "b", 4.55555, 3.39023, "e"));
    RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.locationRecyclerView);
    recyclerView.setHasFixedSize(true);
    recyclerView.setAdapter(locationRecyclerAdapter);
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
    recyclerView.setLayoutManager(linearLayoutManager);
    locationRecyclerAdapter.notifyDataSetChanged();
    return view;
}

Please try do that and let me know if there is more issues. 

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
    ((MainActivity) getActivity()).setFragmentName(nameFactory.getNameNL(6));
    View view = inflater.inflate(R.layout.flocationRecycle, container, false);
    locationData.add(new LocationData("a", "a", "a", "b", 4.55555, 3.39023, "e"));
    RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.locationRecyclerView);
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
    recyclerView.setLayoutManager(linearLayoutManager);
    recyclerView.setHasFixedSize(true);
    recyclerView.setAdapter(locationRecyclerAdapter);
    return view;
}

I'm wondering if your adapter depend of a network call. In that case you have to create a Listener and after you receive the data then call recyclerView.setAdapter().

Upvotes: 1

phatnhse
phatnhse

Reputation: 3940

There is many things need to be concern in your code:

  • RecyclerView.setLayoutManager() should be call before RecyclerView.setAdapter()
  • When you call RecyclerView.setAdapter(), no need to call notifyDataSetChanged() again

  • This could lead to NullPointerException. 

    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.flocation, parent, false);

Because it's hard for your ViewGroup to figure out what the context is, try to declare Context field inside RecyclerViewAdapter instead.

Upvotes: -1

AlexTa
AlexTa

Reputation: 5251

The View you are inflating does not contain the RecyclerView you are trying to reference.

According the code you have provided, your RecyclerView is declared within flocationRecycle.xml, but you are inflating flocation.xml instead:

View view = inflater.inflate(R.layout.flocation, container, false);

flocation.xml does not contain any R.id.locationRecyclerView child view, so when you try to reference that RecyclerView, you will get null pointer exception.

RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.locationRecyclerView); //there is no recycler view declared inside view

Upvotes: 1

Yossi Segev
Yossi Segev

Reputation: 607

Your RecyclerView is null because it's not found in your layout XML under your search id (findViewById). My guess is that either you point to the wrong XML or you're searching by the wrong view id.

Upvotes: -1

Stephan
Stephan

Reputation: 16769

You inflate the wrong layout, do:

View view = inflater.inflate(R.layout.flocationRecycle, container, false);

Upvotes: 2

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