使用基于PHP XML的Web API的iOS应用程序

I am fairly new to iOS development and trying make a simple app which will communicate with PHP API. Data request and response will be in XML format only..

this is my php method for login,

function login()
{
    $mainframe = JFactory::getApplication();

    $xmlcnt = array();

    if (!isset($HTTP_RAW_POST_DATA))
    {
        $HTTP_RAW_POST_DATA = file_get_contents("php://input");
    }

    if(empty($HTTP_RAW_POST_DATA))
    {
        $xmlcnt['code'] = "2";
        return $xmlcnt;
    }

    $doc = new DOMDocument();

    $doc->loadXML( $HTTP_RAW_POST_DATA);

    $login_data = $doc->getElementsByTagName( "data" );

    foreach( $login_data as $login )
    {
        $user_nm = $login->getElementsByTagName( "username" );
        $user_nm = $user_nm->item(0)->nodeValue;

        $password = $login->getElementsByTagName( "password" );
        $password = $password->item(0)->nodeValue;

    } ......

and the xmldata look like this "<data><username>testuser</username><password>password</password></data>"

i want to understand how/what should i use in xcode objective-c to send and recieve XML efficiently.

Thank you verymuch

you can check an XML parser for that, here some examples: http://cocoawithlove.com/2011/05/classes-for-fetching-and-parsing-xml-or.html

If you are asking which xml parser to use, Writing your own parser should help a lot in performance. We usually add data compression to keep size of data transfer low. We use simple zip library and also do encryption is needed. Zipping will help a lot if the data size is large