Adding some elements of arraylist to JSONArray and POST it using Volley

Question

I have an Arraylist private ArrayList<Product> listProducts = new ArrayList<>(); I just want to copy some elements (id and quantity) from this ArrayList and save it in a JSONArray so I can POST it.

My current code is this:

JSONObject obj = new JSONObject();
JSONArray cartitems = new JSONArray();
  for (int i=0; i < listProducts.size(); i++) {
     try {
         obj.put("id", id);
         obj.put("quantity", quantity);
         cartitems.put(obj);
     }catch (JSONException e) {
         throw new RuntimeException(e);
         }
     }

After saving the JSONArray, I should POST it together with other values to PHP using Volley.

Here's my code:

CartRequest cartRequest = new CartRequest(total_amount, user_id, date, time, cartitems);
RequestQueue queue = Volley.newRequestQueue(ShoppingCartActivity.this);
queue.add(cartRequest);

Here's my Volley Request:

public class CartRequest extends StringRequest {
private static final String REQUEST_URL = "MY_URL";
private Map<String, String> params;

public CartRequest(String total_amount, String user_id, String date, String time, JSONArray cartitems){
   super(Request.Method.POST, REQUEST_URL, null, null);
   params = new HashMap<>();
   params.put("total_amount", total_amount);
   params.put("user_id", user_id);
   params.put("date", date);
   params.put("time", time);
   params.put("cartitems", cartitems);
}

@Override
public Map<String, String> getParams() {
    return params;
    }
}

But I'm getting an ERROR on my Volley Request:

Error:(25, 15) error: method put in interface Map<K,V> cannot be applied to given types;
required: String,String
found: String,JSONArray
reason: actual argument JSONArray cannot be converted to String by method invocation conversion
where K,V are type-variables:
K extends Object declared in interface Map
V extends Object declared in interface Map

Can somebody help me about this? I am new in Android and I am not sure if what I am doing wrong. Thanks in advance.

try this params.put("cartitems", String.valueOf(cartitems)); — Vishal Patoliya ツ
– Vishal Patoliya ツ, Commented Jul 20, 2016 at 11:35
JSONObject obj; for (int i=0; i < listProducts.size(); i++) { obj = new JSONObject(); ...} — Vishal Patoliya ツ
– Vishal Patoliya ツ, Commented Jul 20, 2016 at 11:41

Vishal Patoliya ツ · Accepted Answer · 2016-07-20 11:40:33Z

1

Replace it

JSONObject obj;
JSONArray cartitems = new JSONArray();
  for (int i=0; i < listProducts.size(); i++) {
     obj = new JSONObject();
     try {
         obj.put("id", id);
         obj.put("quantity", quantity);
         cartitems.put(obj);
     }catch (JSONException e) {
         throw new RuntimeException(e);
         }
     }

AND

public CartRequest(String total_amount, String user_id, String date, String time, JSONArray cartitems){
   super(Request.Method.POST, REQUEST_URL, null, null);
   params = new HashMap<>();
   params.put("total_amount", total_amount);
   params.put("user_id", user_id);
   params.put("date", date);
   params.put("time", time);
   params.put("cartitems", String.valueOf(cartitems));
}

edited Jul 20, 2016 at 11:40

answered Jul 20, 2016 at 11:36

Vishal Patoliya ツ

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3 Comments

April G Over a year ago

Thanks, no ERROR anymore. But I'll have to check if my JSONArray is actually working.

Vishal Patoliya ツ Over a year ago

put your jsonObject as new in for loop @AprilG

April G Over a year ago

Yes I already did, I'm making my PHP file now to see if it's posted.

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