RecyclerView Not showing data from Json array

Question

Whenever i try to add data to recycler view, the recycler view doesn't show any data. I tried debugging the program and I am successfully getting JSON data using Retrofit into the application(Checked by printing it in Log). But RecyclerView shows no data.Here is my code:

CartActivity.java

 public class CartActivity extends AppCompatActivity {
RecyclerView listshowrcy;
List<CartDisplay>  cartlist = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cart);

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(API.BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .build();
    API api = retrofit.create(API.class);
    String username = getIntent().getStringExtra("Username");
    Call<List<CartDisplay>> call = api.getCartContent(username);
    call.enqueue(new Callback<List<CartDisplay>>() {
        @Override
        public void onResponse(Call<List<CartDisplay>> call, Response<List<CartDisplay>> response) {
            List<CartDisplay> cart = response.body();
            for(CartDisplay cartContent : cart){
                cartlist.add(cartContent);
            }
        }

        @Override
        public void onFailure(Call<List<CartDisplay>> call, Throwable t) {

        }
    });

    listshowrcy = (RecyclerView)findViewById(R.id.cartList);
    listshowrcy.setHasFixedSize(true);
    CartAdapter cardadapter = new CartAdapter(cartlist,this,username);
    listshowrcy.setAdapter(cardadapter);
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
    listshowrcy.setLayoutManager(linearLayoutManager);



}
}

CartAdapter.java

public class CartAdapter extends RecyclerView.Adapter<CartAdapter.Holderview> {
private List<CartDisplay> cartlist;
private Context context;
private String username;

public CartAdapter(List<CartDisplay> cartlist, Context context,String username) {
    this.cartlist = cartlist;
    this.context = context;
    this.username = username;
}

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

@Override
public void onBindViewHolder(Holderview holder, int position) {
    holder.pname.setText(cartlist.get(position).getP_name());
    holder.pquant.setText(cartlist.get(position).getQuantity());
    holder.price.setText(String.valueOf(cartlist.get(position).getPrice()));
}

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

class Holderview extends RecyclerView.ViewHolder
{
    TextView pname;
    TextView pquant;
    TextView price;

    Holderview(View itemview){
        super(itemview);
        pname = (TextView)itemview.findViewById(R.id.product_name);
        pquant = (TextView)itemview.findViewById(R.id.product_quant);
        price = (TextView)itemview.findViewById(R.id.product_price);
    }

}

}

score 1 · Answer 1 · answered Apr 11 '18 at 17:11

After you get your response you must notify adapter, that data has changed:

    @Override
    public void onResponse(Call<List<CartDisplay>> call, Response<List<CartDisplay>> response) {
        List<CartDisplay> cart = response.body();
        cartList.clear(); // don't forget to clear list, to avoid duplicates
        for(CartDisplay cartContent : cart){
            cartlist.add(cartContent);
        }
        adapter.notifyDataSetChanged();
    }

Another way: you can create method: adapter.setData(cardList) And there refresh adapter data and call notifyDataSetChanged()

score 0 · Accepted Answer · answered Apr 11 '18 at 17:12

In addition to @kdblue's answer, there is another issue with your code. The adapter doesn't know that new data has been added to the underlying list.

You can either use notifyDataSetChanged:

List<CartDisplay> cart = response.body();
for(CartDisplay cartContent : cart){
    cartlist.add(cartContent);
}
cardadapter.notifyDataSetChanged();

Or let the adapter handle new items directly, by adding a method to the adapter like:

public void add(CartDisplay cartDisplay) {
  cartlist.add(user);
  notifyItemInserted(cartlist.size());
}

And adding the items directly to the adapter:

List<CartDisplay> cart = response.body();
for(CartDisplay cartContent : cart){
    cardadapter.add(cartContent);
}

Be aware that you will have to change you code structure to apply these strategies.

If an answer helped you solve your problem, consider marking it as accepted so others users can find it more easily. :) — Leonardo Lima, Apr 11 '18 at 19:58

RecyclerView Not showing data from Json array

2 Answers2