Populating RecyclerView Using Volley in Fragments

Question

I am using Volley to parse Json and populate my Recyclerview in a Fragment. I have found similar threads where solutions included placing adapter in the onResponse method or placing setAdapter before setLayoutManager which have not worked for me. I have tried logging the Json which worked so I am certain the issue is related to the adapter.

I have included the code in my fragment as well as the adapter class.

I have tried different emulators, setting the adapter in different methods and notifying adapter that dataset changed.

private RequestQueue mQueue;


@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    mlayoutManager = new LinearLayoutManager(getContext());

    final RecyclerView.Adapter adapter = new WatchListAdapter(names, names, names, names, names);

    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(mlayoutManager);


    mQueue = Volley.newRequestQueue(getContext());
    String url = "https://api.coingecko.com/api/v3/coins/markets?vs_currency=gbp";
    JsonArrayRequest request = new JsonArrayRequest(Request.Method.GET, url, null, new Response.Listener<JSONArray>() {
        @Override
        public void onResponse(JSONArray response) {



            for(int i = 0; i<response.length();i++){
                JSONObject obj = null;
                try {
                    obj = response.getJSONObject(i);
                } catch (JSONException e) {
                    e.printStackTrace();
                }

                String name = null;
                try {
                    name = obj.getString("id");
                    names.add(name);

                    adapter.notifyDataSetChanged();


                } catch (JSONException e) {
                    e.printStackTrace();
                }



            }


        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Log.i("Volley in Tab4", "not working");

        }
    });
    mQueue.add(request);

This is the adapter used.

public class WatchList_CustomRow extends ArrayAdapter {

ArrayList<String> ranks = new ArrayList<>();
ArrayList<String> names = new ArrayList<>();
ArrayList<String> prices = new ArrayList<>();
ArrayList<String> caps= new ArrayList<>();
ArrayList<String> changes = new ArrayList<>();

public WatchList_CustomRow(@NonNull Context context,ArrayList<String> rank1, ArrayList<String> names1, ArrayList<String> prices1, ArrayList<String> caps1, ArrayList<String> changes1) {
    super(context, R.layout.activity_watch_list__custom_row,rank1);
     names = names1;
    prices = prices1;
    caps=caps1;
    changes=changes1;
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    LayoutInflater inflater = LayoutInflater.from(getContext());
    View customView = inflater.inflate(R.layout.activity_watch_list__custom_row, parent, false);

    String singleRank = getItem(position);
    String singleName = names.get(position);
    String singlePrice = prices.get(position);
    String singleCap= caps.get(position);
    String singleChange = changes.get(position);


    TextView rankTextView = customView.findViewById(R.id.rankTextView);
    TextView nameTextView = customView.findViewById(R.id.WatchedCoinName);
    TextView priceTextView = customView.findViewById(R.id.WatchedCoinPrice);
    TextView capTextView = customView.findViewById(R.id.WatchedcoinMarket);
    TextView changeTextView = customView.findViewById(R.id.WatchCoin24Change);


    rankTextView.setText(singleRank);
    //bodyTextView.setText(singleBody);
    nameTextView.setText(singleName);
    priceTextView.setText(singlePrice);
    capTextView.setText(singleCap);
    changeTextView.setText(singleChange);


    return customView;    }

}

Answer 1

使用RecyclerView.Adapter以及相应的onCreateViewHolder和onBindViewHolder方法来绑定视图和数据

Answer 2

you are not even passing data to Adapter after getting response and you are calling notifyDatasetChanged . and for better JSON parsing use GSON and map your object on Model/Pojo class and get arrayList from of them and pass it to adapter.

kindly post JSON Response as well..then would be able to reply with better solution for you.