Forum ‹ General ‹ Maybe one of you flash experts could help me understand it

[QiX]

Hi everyone,

my co-worker on this project is currently away, and i'm trying to continue something he started.
now i'm getting this weird exception being thrown and i'm having some troubles debugging it.

my problem is this.
we have a component named map_mc (i'm guessing its a MovieClip component because of its name).

this component is throwing an exception of error 1009 (null value).
i've debugged the movie clip and found out this map_mc is set to null.
now, for some reason, I can't find its declaration anywhere! not in any of the .as files and not in the .fla

what i don't understand, is how come I don't get a compilation error if I can't find this component being declared in the first place, and all I get is a runtime error.

do you guys have any idea> maybe i'm not searching for it in the right places.

[Benjaminsen]

There is a few ways an element could be auto defined. Can you paste the code where it errors?

[QiX]

This are the 2 functions:
the first function is the handleJoing function thats being called when a user joins the room:

Code: Select all

private function handleJoin(connection:Connection):void{
         trace("Sucessfully connected to the multiplayer server");                     
         addChild(infoBox);         
         infoBox.Show("waiting");
         this.m_Connection = connection;

         //Add chat to game
         var chat:Chat = new Chat(chat_mc, m_Connection);                     
         m_Connection.send("Map", "MapCenter");      
         
         m_Connection.addMessageHandler("Map", function(m:Message) {            
            str = m.getString(0);
            traceString();                     
            drawFromServer();
            infoBox.Hide();
         })
         
         m_Connection.addMessageHandler("AttackAllowed", function(m:Message) {
            gotoAndStop("error");                        
         })
         m_Connection.addMessageHandler("AttackFaild", function(m:Message, name:String){
            trace("AttackFaild:" + name)
         })

      }

this function dynamically builds a map of tiles according to the information she already got from the server on the MapHandler message.

Code: Select all

      private function drawFromServer():void {
         var newTile:Tile_Nu_gfx;                           
         
         for (var i = 0; i < mapHight; ++i) {
            for (var j = 0; j < mapWidth; ++j) {               
               newTile = new Tile_Nu_gfx("tile" + j + "x" + i, uint(j), uint(i), str.charAt(i * mapWidth + j).toString().charCodeAt(0) - 48);
               newTile.x = (j*tileWidth);                                       
               newTile.y = (i*tileHight);               
               
               newTile.addEventListener(MouseEvent.MOUSE_OVER, OverTile);
               newTile.addEventListener(MouseEvent.MOUSE_OUT, OutOfTile);               
               newTile.addEventListener(MouseEvent.CLICK, handleClick);      
               
               if (mapArr[i * j + j] != 3)//for debug
                  map_mc.addChild(newTile);  // this is the problematic line! 
             }
          }                        
      }


the only other usage i could find of this map_mc component, is at one of the .fla frames actions

Code: Select all

trace("Frame: " + currentLabel.toString());
import flash.display.Loader;
   

var imageLoader:Loader = new Loader();
var imageRequest = new URLRequest("E:/My Dropbox/Holyland.Project/GFX/MapCenter.png");
      
imageLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, imageLoadHandler);   
imageLoader.load(imageRequest);   

function imageLoadHandler(evt:Event) {
   map_mc.addChild(imageLoader.content);
   map_mc.setChildIndex(imageLoader.content,0);
}


Sorry if the code is a bit messy, we'll have to clean and re-organize it once the game's structure is complete

[Benjaminsen]

Sounds to me like map_mc is a timeline object. The reason that its null can be that the mc it's in is not done initializing.

I assume that the timeline code does not error? If not try wrapping your code in a Event.ADDED_TO_STAGE event callback.

[QiX]

what about if we already use this event?

Code: Select all

function HolyLand() {            
         if (stage)
            start();
         else
            addEventListener(Event.ADDED_TO_STAGE, start);      


[Benjaminsen]

Yep that looks about right. The only other thing I can think off is that the map_mc only exist in some of the frames of your container MC

[QiX]

Do You have any idea how to solve it?
I've checked, and the method using this component (map_mc) is being called during the frames where the component is placed.

Thanks again.

[Benjaminsen]

Not unless you want to share the code files.

If so you can send them to me at chris at player.io

/Chris

[QiX]

Until my Buddy who designed it will had a chance checking it out, I was able to do a workaround by deleting the component from the frame and declaring it in the constructor.
this way I could add it to the stage at the time I choose.
it seems to be working ok now

thanks again for your help!