Sending Data From Android To Server with JSON data - php

Question

I am trying sending data from Android application to web server. My android application is working successfully.However php code have problems.
<?php
$json = $_SERVER['HTTP_JSON'];
echo "JSON: \n";
var_dump($json);
echo "\n\n";
$data = json_decode($json,true);
echo "Array: \n";
var_dump($data);
echo "\n\n";
$name = $data['name'];
$pos = $data['position'];
echo "Result: \n";
echo "Name : ".$name."\n Position : ".$pos;
?>
Errors:
Notice: Undefined index: HTTP_JSON in C:\wamp\www\jsonTest.php on line 2
( line 2 : $json = $_SERVER['HTTP_JSON']; )
I couldn't find these problems reason. Can you help me ?
( note: I am using wamp server )
Here is the relevant Android source:
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("10.0.2.2:90/jsonTest.php";);
JSONObject json = new JSONObject();
try {
json.put("name", "flower");
json.put("position", "student");
JSONArray postjson=new JSONArray();
postjson.put(json);
httppost.setHeader("json",json.toString());
httppost.getParams().setParameter("jsonpost",postjson);
System.out.print(json);
HttpResponse response = httpclient.execute(httppost);
if(response != null)
{
InputStream is = response.getEntity().getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
text = sb.toString();
}
tv.setText(text);
}catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
This code works successfully on android side(no error). But php side has problems..
Thanks.

Answer 1

This isn't where your JSON is:
$json = $_SERVER['HTTP_JSON'];
You possibly meant:
$json = $_POST['HTTP_JSON'];
Where HTTP_JSON is the POST variable name you gave to your JSON in your Android app.
The rest of the errors stem from the fact that json_decode is failing because you're not successfully reading the JSON data from the request. You can check the response of json_decode to check if it was successful as follows:
$data = json_decode($json,true);
if( $data === NULL)
{
exit( 'Could not decode JSON');
}
Finally, passing true as the second parameter to json_encode means it will return an associative array, so you'd access elements like so:
$name = $data['name'];
$pos = $data['position'];
Make sure you read the docs for json_encode so you understand what it's doing.
Edit: Your problem is that you're accessing the $_POST parameter by the wrong name. You should be using:
$json = $_POST['jsonpost'];
Since the following line names the parameter "jsonpost":
httppost.getParams().setParameter("jsonpost",postjson);

Answer 2

Since I don't know how the java client sends the request
I would try :
print_r($_SERVER);
print_r($_GET);
print_r($_POST);
To figure out how it does.

Answer 3

try these lines:
httppost.setHeader("Accept", "application/json");
httppost.setHeader("Content-type", "application/json");