Question

I am working on parsing a website in my application.

This is the website: https://raw.github.com/currencybot/open-exchange-rates/master/latest.json

Since I have had some trouble with this, I first tried to get the entire website using a class that extends AsyncTask.

Here is the code which gets EVERYTHING from the website above:

     private class DownloadWebPageTask extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... urls) {
        String response = "";
        for (String url : urls)
        {
            DefaultHttpClient client = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url);
            try
            {
                HttpResponse execute = client.execute(httpGet);
                InputStream content = execute.getEntity().getContent();

                BufferedReader buffer = new BufferedReader(
                        new InputStreamReader(content));
                String s = "";
                while ((s = buffer.readLine()) != null) {
                    response += s;
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return response;
    }
}

However, if you go to the website, I only want the portion after rates. I have to edit the above code so it only returns what I need.

Based on what I understand, I know that I need to change String response to an ArrayList, and I need to change the while loop, but I don’t know what I should do exactly.

I tried using the following code to change the method, but it did NOT work.

     private class DownloadWebPageTask extends AsyncTask<String, Void, ArrayList<String>> {
    @Override
    protected ArrayList<String> doInBackground(String... urls) 
    {
        ArrayList<String> response = new ArrayList<String>();
        for (String url : urls)
        {
            DefaultHttpClient client = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url);
            try
            {
                HttpResponse execute = client.execute(httpGet);
                InputStream content = execute.getEntity().getContent();

                BufferedReader buffer = new BufferedReader(
                        new InputStreamReader(content));
                String s = response.toString();
                while ((s = buffer.readLine()) != null)
                {
                    JSONArray ja = new JSONArray(s);
                    for (int i = 0; i < ja.length(); i++) {
                        JSONObject jo = (JSONObject) ja.get(i);
                        response.add(jo.getString("rates"));
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return response;
    }
}

Any help would be greatly appreciated.

@Dheeraj, UPDATE:

   while ((s = buffer.readLine()) != null)
   {
         JSONArray ja = new JSONObject().getJSONArray("rates"); 
        response.add(ja.toString()); 
   }

This is what I have so far Dheeraj. I am stuck on how to provide the buffer to a JSONObject. Can you help me?

Answer 1

1. Provide the entire buffer you get from the network to a
   JSONObject.
2. [Edit: Corrected thanks to @MisterSquonk] From the JSONObject get the value of “rates” as another JSONObject using getJSONObject("rates").
3. Iterate over the keys of the “rates” object to get its values.

Here’s the code:

private class DownloadWebPageTask extends AsyncTask<String, Void, ArrayList<String>> {
    @Override
    protected ArrayList<String> doInBackground(String... urls) {
        ArrayList<String> response = new ArrayList<String>();
        for (String url : urls) {
            DefaultHttpClient client = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url);
            try {
                HttpResponse execute = client.execute(httpGet);
                InputStream content = execute.getEntity().getContent();
                InputStreamReader isr = new InputStreamReader(content);
                StringBuilder sb = new StringBuilder();
                char[] buffer = new char[1024];
                while (isr.read(buffer) != -1) {
                    sb.append(buffer);
                }
                JSONObject jobj = new JSONObject(sb.toString());
                JSONObject ratesObj = jobj.getJSONObject("rates");
                Iterator<String> keys = ratesObj.keys();
                while (keys.hasNext()) {
                    response.add(ratesObj.getString(keys.next()));
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return response;
    }
}