Actionscript 3 Null Object Error Message - apache-flex

Question

I am building a AS3 only project and got runtime error that said "Cannot access a property or method of a null object reference."
Here is my code:
main.as
public class videoMain extends Sprite{
private var videoPlayer:Player;
public function videoMain (){
loadPlayer()
loadProgress();
}
private function loadProgress():void{
//the code below gave me null object error.....
var byteLoaded:Number=videoPlayer.videoBytesLoaded; //the problem code
var byteTotal:Number=videoPlayer.videoBytesTotal; //the problem code
var percent:Number=Math.floor(byteLoaded/byteTotal)*100;
}
private function loadPlayer():void{
videoPlayer= new Player();
videoPlayer.createPlayer();
}
}
Player.as
public function createPlayer():void{
_loader = new Loader();
_loader.contentLoaderInfo.addEventListener(Event.INIT, onLoaderInit);
_loader.load(new URLRequest(playerType));
}
public function get videoBytesLoaded():Number{
return _Player.getVideoBytesLoaded(); //youtube api method
}
public function get videoBytesTotal():Number{
return _Player.getVideoBytesTotal; //youtube api method
}
private function onLoaderInit(event:Event):void {
_Player=_loader.content;
//only show part of codes....
}
I appreciate any help....Thanks!!!!!

Answer 1

_Player is only defined after the Event.INIT has fired so any call before the _Player value is defined will throw an error.
You should, at the minimum , have this:
public function videoMain (){
loadPlayer()
}
private function onLoaderInit(event:Event):void {
_Player=_loader.content;
//only show part of codes....
loadProgress();
}
but progress events are not static so really you should have an enterFrame event listener in order to listen to the changing values...
private function onLoaderInit(event:Event):void {
_Player=_loader.content;
//only show part of codes....
addEventListener(Event.ENTER_FRAME , enterFrameListener);
}
private function enterFrameListener(event:Event):void
{
loadProgress();
// and here you add some way to remove this event listener when
// the video is fully loaded
}