json decode by PHP

//get_multi_recordset.php
$brands  = getSet($db, "select brand_id from brands where user_id=?", array($user_id));
$categories  = getSet($db, "select category_id from categories where user_id=?", array($user_id));
$subcategories  = getSet($db, "select subcategory_id from subcategories where user_id=?", array($user_id));
$payments  = getSet($db, "select payment_id from payments where user_id=?", array($user_id));

$json                = array('brands'=> $brands, 'categories' => $categories, 'subcategories'  => $subcategories, 'payments'  => $payments);

header("Content-Type: application/json", true);

echo json_encode($json);

//here async, get the response from get_multi_recordset.php, and decode the JSONObject
try {
	JSONObject resp = new JSONObject(response);

	JSONArray brands = resp.getJSONArray("brands");

	String brand_ids="";
	for (int i = 0 ; i < brands.length();="" i++){="" brand_ids+="((JSONObject)" brands.get(i)).getstring("brand_id")="" +="" ",";="" }="" if="" (brand_ids.length()=""> 0)
		brand_ids = brand_ids.substring(0, brand_ids.length() - 1);

} catch (JSONException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}