I am trying to developed one flex 4 appliction using action script 3.0 and php. In which on button click i want to check whether the callRespoder receive any result or not from php function ,but it's not working as actally as i want.It's work only on when i click on the button twice.

esnek Uygulama kodu:

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
               xmlns:s="library://ns.adobe.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx"              
               width="1010" height="620" 
               xmlns:userlogin="services.userlogin.*">
    <fx:Style source="cssStyle/Style.css"/> 
    <fx:Script>
        <![CDATA[           
            import flash.net.navigateToURL;

            import mx.collections.ArrayCollection;
            import mx.controls.Alert;
            import mx.events.FlexEvent;
            import mx.rpc.events.ResultEvent;           
            import valueObjects.LoginDataType;              


            protected function button_click(event:MouseEvent):void
            {
                loginResult.token =userlogin.login 
                                     (uname.text,password.text);

                if(loginResult.lastResult!=null)
                {
                    navigateToURL(new URLRequest 
                                               ('studentmenu.html'));
                }
                else
                {
                    msg.text="Invalid Login";                   
                }               
            }           

            /* protected function msg_dataChangeHandler():void
            {
            if(msg.text=="")
            {
            Alert.show("Invalid Login"+msg.text);   
            }
            else
            {
            Alert.show("Valid Login"+msg.text);
            }
            } */    

        ]]>
    </fx:Script>

<fx:Declarations>   
<s:CallResponder id="loginResult"/>
<userlogin:Userlogin id="userlogin" fault="Alert.show(event.fault.faultString + '\n' + event.fault.faultDetail)" showBusyCursor="true" />
</fx:Declarations>

<mx:Canvas borderColor="#003333" borderVisible="true" borderStyle="solid" width="1010" height="620">
    <mx:Image x="27" y="6" width="52" height="52" source="images/Academia-left.jpg" click="navigateToURL(new URLRequest('http://www.academiadirect.com'))" buttonMode="true"/>  
    <mx:Image x="215" y="11" width="573" height="38" source="images/Academia-center.jpg" click="navigateToURL(new URLRequest('http://www.academiadirect.com'))" buttonMode="true"/>
    <mx:Image x="828" y="10" width="170" height="52" source="images/Tamarind-Academia.gif" click="navigateToURL(new URLRequest('http://www.academiadirect.com'))" buttonMode="true"/>
    <mx:Image x="0" y="117" width="532" height="498" source="images/Academia - Home.jpg" click="navigateToURL(new URLRequest('http://www.academiadirect.com'))" buttonMode="true"/>

    <mx:Image x="650" y="128" width="30" height="26" source="images/Term Planning and Course Management.jpg"/>
    <s:Label x="698" y="128" text="Term Planning and Course Management" styleName="lable"/>
    <mx:Image x="650" y="168" width="30" height="26" source="images/Knowledge Repository Management.jpg"/>
    <s:Label x="698" y="168" text="Knowledge Repository Management" styleName="lable"/>
    <mx:Image x="650" y="208" width="30" height="26"  source="images/Stakeholder Collaboration Management.jpg"/>
    <s:Label x="698" y="208" text="Stakeholder Collaboration Management" styleName="lable"/>
    <mx:Image x="650" y="248" width="30" height="26" source="images/Assessment and Evaluation Management.jpg"/>
    <s:Label x="698" y="248" text="Assessment and Evaluation Management" styleName="lable"/>    
    <mx:Image x="650" y="288" width="30" height="26" source="images/Feedback and  Quality Management.jpg"/>
    <s:Label x="698" y="288" text="Feedback and  Quality Management" styleName="lable"/>
    <mx:Image x="650" y="328" width="30" height="26" source="images/Permissions Management.jpg"/>
    <s:Label x="698" y="328" text="Permissions Management" styleName="lable"/>  
    <s:Label x="0" y="66" text="S t a y       A h e a d" width="100%" height="28" styleName="NamePlate"/>
    <mx:Label x="743" y="379"  width="124" id="msg" visible="true"/>
    <s:Panel x="652" y="399" width="314" height="163" title="Login">
        <s:Label  text="User Name:" styleName="lable" x="35" y="19"/><s:TextInput id="uname" styleName="textbox"  x="141" y="19" />
        <s:Label text="Password:" styleName="lable" x="35" y="48"/><s:TextInput id="password" styleName="textbox"  x="141" y="48" displayAsPassword="true"/>
        <s:Button label="Login" x="120" y="94" id="button" styleName="button"  toolTip="Login" click="button_click(event);"/>
    </s:Panel>  
</mx:Canvas>
</s:Application>

PHP kodu:

<?php
class userlogin
{
    var $username = "root";
    var $password = "";
    var $server = "localhost";
    var $databasename = "tamarind_academia";


    public function userlogin()
    {

        $this->conn = mysqli_connect($this->server,$this->username,$this->password,$this->databasename);
        //$this->throwExceptionOnError($this->conn);
    }



    public function login($username,$password) 
    {       
        $query = mysqli_prepare($this->conn, "SELECT user_id,fname,lname,instid,collid,locid,desigid FROM user_info where uname='".$username."' and pass='".$password."'");
        //$this->throwExceptionOnError();       

        mysqli_stmt_execute($query);
        //$this->throwExceptionOnError();       
        mysqli_stmt_bind_result($query, $row->user_id,$row->fname, $row->lname, $row->instid, $row->collid, $row->locid, $row->desigid);

        if(mysqli_stmt_fetch($query))
            {
          return $row;
            }
        else 
            {
          return null;
            }
    }
}
?>