Context.getSystemService(java.lang.String) null

Question

when I click RecyclerView, I want to capture the data of the rooms in the database, but I get problems. how to capture this data when I click RecyclerView. I'm getting this error in the ArrayAdapter section.

Error: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference

    public class ProductsNewAdapter extends RecyclerView.Adapter<ProductsNewAdapter.ProductViewHolder> {
        Context mCtx;
        private Spinner spinner;
        List<String> Rooms = new ArrayList<String>();
     public ProductsNewAdapter(Context mCtx, List<ProductNew> productList) {
            this.mCtx = mCtx;
            this.productList = productList;

        }
     @Override
        public ProductViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(mCtx).inflate(R.layout.product_laylout_new,
                    parent, false);
            ProductViewHolder productViewHolder = new ProductViewHolder(view);
            return productViewHolder;

        }

        int selectedPosition=-1;


        @Override
        public void onBindViewHolder(final ProductViewHolder holder, final int position) {
            if(selectedPosition==position)
                holder.itemView.setBackgroundColor(Color.parseColor("#25E9F9"));
            else
                holder.itemView.setBackgroundColor(Color.parseColor("#ffffff"));

            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(final View v) {
                    selectedPosition=position;
                    notifyDataSetChanged();

DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference();

    DatabaseReference refRooms = mDatabase.child("0").child("Rooms");

                refRooms.addValueEventListener(new ValueEventListener() {
               @Override
          public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
        for (DataSnapshot snapshot : dataSnapshot.getChildren()){
          spinner = (Spinner) v.findViewById(R.id.spinnerMain);
          ViewGroup parent = null;
View view =
LayoutInflater.from(parent.getContext()).inflate(R.layout.product_laylout_new,
                                    parent, false);

                        String data = snapshot.getValue(String.class);
                       Rooms.add(data);
                          //  addListenerOnSpinnerItemSelection();
                            }
                        }

                        @Override
                        public void onCancelled(DatabaseError databaseError) {
                        }
                    });
                }
            });

Likely the Context you're passing to constructor is null and it NPEs in LayoutInflater.from(). Have a look at the code where you create this adapter. — laalto
– laalto, Commented Jul 11, 2019 at 9:05

Manoj Perumarath · Accepted Answer · 2019-07-11 09:18:24Z

2

Try this,

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

answered Jul 11, 2019 at 9:18

Manoj Perumarath

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6 Comments

stackengineer Over a year ago

I'm getting this error: "java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.view.ViewGroup.getContext()' on a null object reference"

Ashish Over a year ago

@stackengineer you can use context of parent.

Manoj Perumarath Over a year ago

please post the initialization of your recyclerview @stackengineer

stackengineer Over a year ago

I don't understand what you mean @ManojPerumarath

Manoj Perumarath Over a year ago

@stackengineer Where are you using this class ProductsNewAdapter ?

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