Android parsing Json error

Question

I having an error while parsing json array in my android application.

My json object is in the following form:

{"post":[
      [{"0":"all the best to every one...!!","post":"all the best to every one...!!"},
     {"0":"hello every one...","post":"hello every one..."}]
]}

My java file in android is as follows:

public class Newsactivity extends ListActivity {
private static final String TAG_SUCCESS = "";
private ProgressDialog pDialog;

JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> postsList;

private static String url_all_products = "myurl";
private static final String TAG_POST = "post";
JSONArray posts = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.allposts);        
    postsList = new ArrayList<HashMap<String, String>>();
    new LoadAllProducts().execute();
    ListView lv = getListView();
}
class LoadAllProducts extends AsyncTask<String, String, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(Newsactivity.this);
        pDialog.setMessage("Loading posts. Please wait...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();
    }
    protected String doInBackground(String... args) {
        List<NameValuePair> params = new ArrayList<NameValuePair>();

        JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
        Log.d("All Posts: ", json.toString());
        try {
            posts = json.getJSONArray(TAG_POST);
            for (int i = 0; i < posts.length(); i++) {
                JSONObject c = posts.getJSONObject(i);
                String post = c.getString(TAG_POST);

                HashMap<String,String> map = new HashMap<String,String>();
                map.put(TAG_POST, post);

                postsList.add(map);
            }

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

        return null;
    }
    protected void onPostExecute(String file_url) {
        pDialog.dismiss();
        runOnUiThread(new Runnable() {
            public void run() {

                ListAdapter adapter = new SimpleAdapter(
                        Newsactivity.this, postsList,
                        R.layout.singlepost, new String[] { TAG_POST},
                        new int[] { R.id.pid});

                setListAdapter(adapter);
            }
        });
    }
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_newsactivity, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

}

I am getting a fatal exception starting this activity. This code is modified code of an online tutorial on json parsing. As I am new to android I am unable to find where the id is. So, please help me. Thank you.

makeHttpRequest is most likely failing because you aren't passing a valid url — samgak
– samgak, Commented Mar 10, 2015 at 1:06
I am not understanding how to indent it here.. can you help me? @mr.icetea — lonecoder
– lonecoder, Commented Mar 10, 2015 at 1:31
Your 'doInBackground(String...args)' method contains arguments but your call for '.execute()' does not have any arguments. — GermaineJason
– GermaineJason, Commented Mar 10, 2015 at 1:39

Koma Yip · Accepted Answer · 2015-03-10 02:11:29Z

1

I am afraid that your json format is "a little bit strange" (or i may say it is in a different format with what your code is trying to do) according to your code. As you can see, there are two "[" after the first "post", which means the array of elements is actually inside another array.

{"post":[ // first '['
  [ // second '['
    {"0":"all the best to every one...!!","post":"all the best to every one...!!"},
    {"0":"hello every one...","post":"hello every one..."}
  ]
]}

so to make it correct, do following

try {
        posts = json.getJSONArray(TAG_POST);
        posts = posts.getJSONArray(0) // to get the first array
        for (int i = 0; i < posts.length(); i++) {
            JSONObject c = posts.getJSONObject(i);
            String post = c.getString(TAG_POST);

            HashMap<String,String> map = new HashMap<String,String>();
            map.put(TAG_POST, post);

            postsList.add(map);
        }

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

edited Mar 10, 2015 at 2:11

answered Mar 10, 2015 at 1:59

Koma Yip

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1 Comment

Koma Yip Over a year ago

yes , what I mean "wrong" is the format is not what his code is doing and I don't know the json format or the code means "correct" to him

RBK · Accepted Answer · 2015-03-10 03:50:32Z

as your json responce having nested array you need to code like this...

JSONObject json; = jParser.makeHttpRequest(url_all_products, "GET", params);

    Log.d("All Posts: ", json.toString());

    try {

        posts = json.getJSONArray(TAG_POST);

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

            subposts = posts.getJSONArray(i);

            for (int j = 0; j < subposts.length(); j++) {

                JSONObject c = subposts.getJSONObject(i);
                String post = c.getString(TAG_POST);

                HashMap<String, String> map = new HashMap<String, String>();
                map.put(TAG_POST, post);

                postsList.add(map);

            }
        }

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

meda · Accepted Answer · 2015-03-10 17:55:16Z

0

Try this:

posts = json.getJSONArray(TAG_POST);
for (int i = 0; i < posts.getJSONArray(0).length(); i++) {
    JSONObject c = posts.getJSONArray(0).getJSONObject(i);
    String post = c.getString("0");

    HashMap<String,String> map = new HashMap<String,String>();
    map.put(TAG_POST, post);

    postsList.add(map);
}

answered Mar 10, 2015 at 17:55

meda

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