What does this mean for Flash and Flex developers? It means that we can finally use the same tools that we use to develop our Flash and Flex applications, be it the Flash IDE, Flex Builder, FDT/Eclipse or Flash Develop, and writing Actionscript 3 code to build apps that will run on mobile handsets that support Flash Player 10. No longer are we restricted to the limited features of FlashLite and the Actionscript 2 language. I expect to see an explosion of developers from within the Flash and Flex communities jump on board the mobile bandwagon in 2010.

In addition to the Flash Player 10 announcement, Adobe in partnership with Nokia, also announced the $10 Million Open Screen Project Fund. The Open Screen Project Fund encourages the use of Adobe tools and existing developer skills to create exciting and unique Flash applications for millions of Nokia devices. With the widespread adoption of Flash Player 10 in the mobile world, this should help solidify Flash as the ubiquitous platform for mobile development.

Naturally, there will always be the Flash haters who prefer to run native apps and live in a Flash-free world. And then there’s the iPhone, which is a subject better left for another day.

Turns out that when the stage is initialized, its stageWidth and stageHeight properties are 0 until a Stage RESIZE event is triggered. This event is dispatched when the scaleMode property of the Stage object is set to StageScaleMode.NO_SCALE and the SWF file is resized ie. when the stage is rendered by the Flash Player. So if you need to add a display object onto the stage and its positioning is dependent on the stageWidth or stageHeight properties at runtime, it’s best handled by a listener that is subscribed to the Stage RESIZE event.

Interestingly, despite universal claim that the Flash Player behaves exactly the same on all browsers, this problem only appears in a couple of browser/plugin configurations, namely FireFox/OSX and IE/Win. And strangely, on Safari and Firefox/Win, the RESIZE event is not even dispatched on page load, and neither does the Flash Player register the stageWidth and stageHeight properties as being 0. I have not tested the problem on other platforms but you are certainly welcome to do so yourselves and report your observations in the comments section. Eventually, it would be nice if we can get a straight answer from Adobe concerning this bug.

In the following demo code, I’ve attached a Sprite containing a Rectangle graphic and a TextField, to the stage once before the RESIZE event and once, after. You can see the results here.

package
{
  import flash.text.*;
  import flash.display.*;
  import flash.events.*;

  public class Demo extends Sprite
  {
    private var rect1:Sprite;
    private var rect2:Sprite;

    public function Demo()
    {
      rect1 = createNewRect("Before stage resize event.");
      rect1.x = 0;
      rect1.y = 0;
      addChild(rect1);

      stage.scaleMode = StageScaleMode.NO_SCALE;
      stage.align = StageAlign.TOP_LEFT;
      stage.addEventListener(Event.RESIZE, resizeHandler);
    }

    private function createNewRect(str:String):Sprite
    {
      var rect:Sprite = new Sprite();
      rect.graphics.beginFill(0x99CCFF);
      rect.graphics.drawRect(0, 0, 200, 100);
      rect.graphics.endFill();

      var fmt:TextFormat = new TextFormat();
      fmt.font = "Arial";
      fmt.size = 12;

      var tf:TextField = new TextField();
      tf.width = 200;
      tf.height = 100;
      tf.multiline = true;
      tf.defaultTextFormat = fmt;
      tf.text = str + "\n" + "stage.stageWidth: " + stage.stageWidth + "\n" +
            "stage.stageHeight: " + stage.stageHeight;

      rect.addChild(tf);
      return rect;
    }

    private function resizeHandler( event:Event ):void
    {
      if (rect2 != null && contains(rect2)) {
        removeChild(rect2);
      }

      rect2 = createNewRect("After stage resize event.");
      rect2.x = (stage.stageWidth - rect2.width) / 2;
      rect2.y = (stage.stageHeight - rect2.height) / 2;
      addChild(rect2);
    }
  }
}

Download the latest Flash Player update and check out this sample video which my friend Colin has kindly uploaded.

Download and install the latest Flash Player 9 debugger version (9.0.r47).

Install the Flash Tracer extension for Firefox.

In the Preference settings for Flash Tracer, set the path to your flashlog:
Macintosh HD:Users:YourUserName:Library:Preferences:Macromedia:Flash Player:Logs:flashlog.txt

In XP, you’d find flashlog.txt here:
C:\Documents and Settings\YourUserName\Application Data\Macromedia\Flash Player\Logs\flashlog.txt

Fire up Flash Tracer from the Tools menu in Firefox.

Go to Adobe’s home page and voila! Enjoy the debugger in its full glory!

You wouldn’t think that Adobe’s developers would be so careless to leave their trace statements running in their published files, but I guess they’re only human like the rest of us.