Android Json Tutorial

This tutorial describes how to use JSON with Android. JSON stands for (Java Script Object Notation). It is a simple and light-weight data interchange format that can be easily read by humans and machines. JSON is a text format that is language independent. It represents data in a text format so that can be easily parsed.


Introduction to JSON

JSON uses two different of structures:

-> Collection of name/value pair
-> Array



Lets take the api from the Android hive:
                                                               http://api.androidhive.info/contacts/

{     "contacts": [         {                 "id": "c200",                 "name": "Ravi Tamada",                 "email": "ravi@gmail.com",                 "address": "xx-xx-xxxx,x - street, x - country",                 "gender" : "male",                          }                  .   ] }

Creating New Android Project:

webservice Function:

public static ArrayList<HashMap<String, String>> JsonResponseUrl(
          String url)    throws JSONException{

arraylist =new ArrayList<HashMap<String,String>>();
JSONArray json_array = new JSONArray(url);

for (int i = 0; i < json_array.length(); i++) 
{

HashMap<String, String> map = new HashMap<String, String>();
jsonobject = json_array.getJSONObject(i);
map.put("sms", jsonobject.getString("contacts"));
arraylist.add(map);


    }
return arraylist;


}

:Http Connection:

 public static String executeHttpGet(String url) throws Exception {
        BufferedReader in = null; int statusCode = 0;
        try {
            HttpClient client = getHttpClient();
            HttpGet request = new HttpGet();
            request.setURI(new URI(url));
            HttpResponse response = client.execute(request);
            in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            statusCode = response.getStatusLine().getStatusCode();
       
                Log.d("Http Request------------------>", ""+statusCode);
             
           if(statusCode == 200)
           {
            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();

            String result = sb.toString();
            return result;
           }
       
        } finally {
        Log.d("Http Request1------------------>", ""+statusCode);
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
return null;
   }




Implement  on AsyncTask:

class ProgressBar_History extends AsyncTask<Void, Void, Void>
 {

@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
history_url = String.format("http://api.androidhive.info/contacts/");

history_url1 = Utility.urlEncode(history_url);

try {
Log.d(" convert url ----------------->", ""+history_url1);
   
url =executeHttpGet(history_url1);

Log.d("url responce from JSON----------------->", ""+url);
if(url != null)
{

arraylist_history = jsonhistoryResponseUrl(url);

}else{
mProgressDialog.dismiss();
Log.d("Server Error", "");
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return null;
}

@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
mProgressDialog = ProgressDialog.show(getActivity(),"history", "Please Wait...",true);
}

@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
mProgressDialog.dismiss();
if(arraylist_history != null){


adapter = new HistoryListAdapter(getActivity(), R.layout.row_smshistory_list, arraylist_history);
history_list.setAdapter(adapter);

}
}
}