TheSM TheSM - 6 months ago 24
PHP Question

String cannot be converted to JSONArray

I am trying to get data from a php file.

This is my PHP code:

$sql=mysql_query("select * from `tracking`");
while($row=mysql_fetch_assoc($sql))
$output[]=$row;
print(json_encode($output));


And I really need all the data. This is the code I use to get and convert the data:

String result = null;
InputStream is = null;
StringBuilder sb = null;

ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://server/getData.php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch(Exception e) {
Log.e("log_tag", "Error in http connection"+e.toString());
}

//convertion de la réponse en String
try {
//BufferedReader reader = new BufferedReader(new InputStreamReader(is, "iso-8859-1"),8);
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"UTF-8"),8);
sb = new StringBuilder();
sb.append(reader.readLine() + "\n");

String line="0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
//sb.append(line);
}

is.close();
result=sb.toString();
} catch(Exception e) {
Log.e("log_tag", "Error converting result "+e.toString());
}

// Affectation des données
try {
JSONArray jArray = new JSONArray(result);
Log.d("jArray", ""+jArray);
JSONObject json_data= null;

for(int i=0; i<jArray.length(); i++) {
p = new Position();
json_data = jArray.getJSONObject(i);

Log.d("js", ""+json_data);
id=json_data.getInt("id");
lat=(float) json_data.getDouble("lat");
lon=(float) json_data.getDouble("lon");
speed=(float) json_data.getDouble("speed");
alt=json_data.getDouble("alt");
time=json_data.getString("time");
date=json_data.getString("date");

p.setId(id);
p.setLat(lat);
p.setLon(lon);
p.setSpeed(speed);
p.setAlt(alt);
p.setDate(date);
p.setTime(time);

datasource.createPosition(p);
}
} catch(JSONException e1) {
Log.e("JSONEX", ""+e1);
} catch (ParseException e1) {
e1.printStackTrace();
}


This really works on emulator nicely but not on my android phone and I don't get the reason.

Now this is my json result from the server:


[{"id":"180","lat":"33.894707","lon":"-6.327312","speed":"0.00000","alt":"397","date":"29/07/2012","time":"23:44"}]


It's a valid
JSONArray
validated on http://jsonlint.com/

Answer

I found what was wrong with JSON. I found at the beginning a character "?" added somewhere in the code and it was not visible until I stored the logCat entry to a file. So I added the code line and it works fine now.

result = result.substring(1);

I hope it may help someone in the future thanx to Waqas