Android JSON Parsing "JSONException; Value <!DOCTYPE

Question

Im trying to the use the following code below to parse JSON data, The website requires a API key, which for now is stored as a string in my strings.xml.

public class JSONParser {

static InputStream is = null;
static JSONArray jarray = null;
static String json = "";

// constructor
public JSONParser() {
}

public JSONArray getJSONFromUrl(String url) {
    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);

        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();
        is = httpEntity.getContent();           

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    try {

        JSONObject jObj = new JSONObject(json);
        jarray = jObj.getJSONArray("systems");
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    return jarray;
}
}

MainActivity.

 public class MainActivity extends ListActivity {
private Context context;
private static String url = "https://api.company.com/api/systems";

private static final String TAG_SYSTEM = "systems";
private static final String TAG_SYSTEM_ID = "system_id";

ArrayList<HashMap<String, String>> jsonlist = new ArrayList<HashMap<String, String>>();

ListView lv ;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    new ProgressTask(MainActivity.this).execute();
}
private class ProgressTask extends AsyncTask<String, Void, Boolean> {
    private ProgressDialog dialog;

    private ListActivity activity;

    // private List<Message> messages;
    public ProgressTask(ListActivity activity) {
        this.activity = activity;
        context = activity;
        dialog = new ProgressDialog(context);
    }

    /** progress dialog to show user that the backup is processing. */
    private Context context;

    protected void onPreExecute() {
        this.dialog.setMessage("Progress start");
        this.dialog.show();
    }

    @Override
    protected void onPostExecute(final Boolean success) {
        if (dialog.isShowing()) {
            dialog.dismiss();
        }
        ListAdapter adapter = new SimpleAdapter(context, jsonlist,          
        R.layout.list_item, new String[] { TAG_SYSTEM, TAG_SYSTEM_ID
                 }, new int[] {
                R.id.vehicleType, R.id.vehicleColor });

        setListAdapter(adapter);
        // selecting single ListView item
         lv = getListView();
    }
    protected Boolean doInBackground(final String... args) {

        JSONParser jParser = new JSONParser();
        //Using APIKEY from strings.xml
        String apikey = getString(R.string.apikey);
        // getting JSON string from URL
        JSONArray json = jParser.getJSONFromUrl(url + "&key=" + apikey);

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

            try {
                JSONObject c = json.getJSONObject(i);

                String vcolor = c.getString(TAG_SYSTEM_ID);

                HashMap<String, String> map = new HashMap<String, String>();

                // adding each child node to HashMap key => value
                map.put(TAG_SYSTEM_ID, vcolor);
                jsonlist.add(map);
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return null;
    }
}

}

Here is my current LogCat

  04-30 15:39:53.775: E/JSON Parser(9814): Error parsing data org.json.JSONException: Value   <!DOCTYPE of type java.lang.String cannot be converted to JSONObject
04-30 15:39:53.780: E/AndroidRuntime(9814): FATAL EXCEPTION: AsyncTask #1
04-30 15:39:53.780: E/AndroidRuntime(9814): java.lang.RuntimeException: An error occured while executing doInBackground()
04-30 15:39:53.780: E/AndroidRuntime(9814):     at android.os.AsyncTask$3.done(AsyncTask.java:299)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.lang.Thread.run(Thread.java:856)
04-30 15:39:53.780: E/AndroidRuntime(9814): Caused by: java.lang.NullPointerException
04-30 15:39:53.780: E/AndroidRuntime(9814):     at com.jitesh.androidjsonparser.MainActivity$ProgressTask.doInBackground(MainActivity.java:102)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at com.jitesh.androidjsonparser.MainActivity$ProgressTask.doInBackground(MainActivity.java:1)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at android.os.AsyncTask$2.call(AsyncTask.java:287)
04-30 15:39:53.780: E/AndroidRuntime(9814):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
04-30 15:39:53.780: E/AndroidRuntime(9814):     ... 5 more
04-30 15:40:03.035: E/WindowManager(9814): Activity com.jitesh.androidjsonparser.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4257ae80 that was originally added here
04-30 15:40:03.035: E/WindowManager(9814): android.view.WindowLeaked: Activity com.jitesh.androidjsonparser.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4257ae80 that was originally added here
04-30 15:40:03.035: E/WindowManager(9814):  at android.view.ViewRootImpl.<init>(ViewRootImpl.java:402)
04-30 15:40:03.035: E/WindowManager(9814):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:311)
04-30 15:40:03.035: E/WindowManager(9814):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224)
04-30 15:40:03.035: E/WindowManager(9814):  at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149)
04-30 15:40:03.035: E/WindowManager(9814):  at android.view.Window$LocalWindowManager.addView(Window.java:554)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.Dialog.show(Dialog.java:277)
04-30 15:40:03.035: E/WindowManager(9814):  at com.jitesh.androidjsonparser.MainActivity$ProgressTask.onPreExecute(MainActivity.java:69)
04-30 15:40:03.035: E/WindowManager(9814):  at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
04-30 15:40:03.035: E/WindowManager(9814):  at android.os.AsyncTask.execute(AsyncTask.java:534)
04-30 15:40:03.035: E/WindowManager(9814):  at com.jitesh.androidjsonparser.MainActivity.onCreate(MainActivity.java:47)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.Activity.performCreate(Activity.java:5206)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.ActivityThread.access$600(ActivityThread.java:140)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
04-30 15:40:03.035: E/WindowManager(9814):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-30 15:40:03.035: E/WindowManager(9814):  at android.os.Looper.loop(Looper.java:137)
04-30 15:40:03.035: E/WindowManager(9814):  at android.app.ActivityThread.main(ActivityThread.java:4898)
04-30 15:40:03.035: E/WindowManager(9814):  at java.lang.reflect.Method.invokeNative(Native Method)
04-30 15:40:03.035: E/WindowManager(9814):  at java.lang.reflect.Method.invoke(Method.java:511)
04-30 15:40:03.035: E/WindowManager(9814):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
04-30 15:40:03.035: E/WindowManager(9814):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
04-30 15:40:03.035: E/WindowManager(9814):  at dalvik.system.NativeStart.main(Native Method)

Can someone please help me fix these issues im having. Thank you in advance if you take the time to read and help.

Answer 1

The service obviously returns a server error. Try to either call the service with the same parameters from a client where you can see the response, or log the String response before you try to parse it to JSON. The exact server response will most certainly tell you what's wrong with your query.

Answer 2

It is an error from your server. You want to check status code by calling httpResponse.getStatusLine().getStatusCode()

If the status code is 200, then you can start parsing your result. Otherwise, it is an error, you have to handle the error gracefully.