php帮助从Xcode读取json

can someone help me with the syntax in php to read the following:

{"screencast":{"id":null,"subject":null,"body":null,         "dataUrl":null,"dataMedium":null,"createdOn":null,"author":null}}

i can do the query but need to read the values and have different opinions on how to use json json_decode and url decode with a post.

Do you want something like that?

if

$data = '{"screencast":{"id":null,"subject":null,"body":null, "dataUrl":null,"dataMedium":null,"createdOn":null,"author":null}}';

then

$decodedData = json_decode($data, true);

and

$screencast = $decodedData['sceencast'];
$id = $screencast['id'];
$subject = $screencast['subject'];
// and so on...