Using “put” method of JSONObject in for loop (java)

I’m trying to use JSONObject’s put method in for loop. But I’m not getting Expected output.

Expected output:

{"Result":[{"PostOfficeName":"Bhajan Pura","Pincode":"110096"},{"PostOfficeName":"Gokulpuri","Pincode":"110094"}, and so on...]}

OutPut I’m getting:

{"Result":[{"PostOfficeName":"Bhajan Pura","Pincode":"110096"}]}

here is my code:

try {
            JSONObject obj = new JSONObject(loadJsonfromAssets());
            JSONArray arr = obj.getJSONArray("Sheet1");

            JSONObject finalObj = new JSONObject();
            JSONArray ResultArray = new JSONArray();
            JSONObject infoObj = new JSONObject();

            for (int i=0; i<arr.length();i++){
                JSONObject obj1 = arr.getJSONObject(i);
                if (obj1.getString("City").equals("New Delhi")){
Log.d("postal", "Found!");
Toast.makeText(this, "" + obj1.getString("Pincode"), Toast.LENGTH_SHORT).show();
infoObj.put("PostOfficeName", obj1.getString("PostOfficeName"));
                    infoObj.put("Pincode",obj1.getString("Pincode"));
                    ResultArray.put(infoObj);
                }
            }
            finalObj.put("Result", ResultArray);

            System.out.println(finalObj);
   
        } catch (JSONException e) {
            e.printStackTrace();
        }

Answer

Have you tried moving the construction of infoObj inside the loop. By having it outside, you’re maintaining state across loop iterations. I suspect you’re just updating the same json object each time and adding it to the JSON array. Not sure why you NOT getting duplicates because I do when I run your code.

Change it to this makes it “better”

try {
    JSONObject obj = new JSONObject(loadJsonfromAssets());
    JSONArray arr = obj.getJSONArray("Sheet1");

    JSONObject finalObj = new JSONObject();
    JSONArray ResultArray = new JSONArray();

    for (int i=0; i<arr.length();i++){
        JSONObject obj1 = arr.getJSONObject(i);
        if (obj1.getString("City").equals("New Delhi")) {
          Log.d("postal", "Found!");
          Toast.makeText(this, "" + obj1.getString("Pincode"), 
          Toast.LENGTH_SHORT).show();

          // move instantiation INSIDE loop
          JSONObject infoObj = new JSONObject();

          infoObj.put("PostOfficeName", obj1.getString("PostOfficeName"));
          infoObj.put("Pincode",obj1.getString("Pincode"));
          ResultArray.put(infoObj);
        }
    }
    finalObj.put("Result", ResultArray);

    System.out.println(finalObj);

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