Question

I have devised the following method for catching errors throughout my AS3 applications:

In the Document class, define the following methods:

//This is the handler for listening for errors
protected function catchError(event:ErrorEvent):void 
{ 
  displayError('Error caught: ' + event.text);
}

//Creates a MovieClip with a TextField as the child.
//Adds the MC to the stage
protected function displayError(msg:String):void
{
  var errorMC:MovieClip = new MovieClip();
  errorMC.graphics.beginFill(0xffffff);
  errorMC.graphics.drawRect(0, 0, stage.stageWidth, stage.stageHeight);
  errorMC.graphics.endFill();

  var errorTxt:TextField = new TextField();
  errorTxt.multiline = true;
  errorTxt.width = stage.width;
  errorTxt.height = stage.height;
  errorTxt.selectable = true;
  addChild(errorMC);
  addChild(errorTxt);

  errorTxt.text = 'Error(s) Caught: \n' + msg;
}

To deal with classes that are used within the Document class I add the following so that I can register the previously mentioned functions:

protected var errorCatcher:Function;
protected var displayError:Function;

public function setErrorDisplayer(f:Function):void
{
  displayError = f;
}

public function setErrorCatcher(f:Function):void
{
  errorCatcher = f;
}

Now, I can display errors in the SWF at runtime, when testing the application in the browser.

For example:
(I didn’t test the following it’s just an example)

//Document class
package com
{
  import flash.display.MovieClip;
  import flash.event.ErrorEvent;
  import flash.text.TextField;
  import com.SomeClass;

  public class Document extends MovieClip
  {
    protected var someClass:SomeClass = new SomeClass();

    public function Document():void 
    {
      someClass.setErrorCatcher(catchError);
      someClass.setErrorDisplayer(displayError);
    }

    protected function catchError(event:ErrorEvent):void 
    { 
      displayError('Error caught: ' + event.text);
    }

    protected function displayError(msg:String):void
    {
      var errorMC:MovieClip = new MovieClip();
      errorMC.graphics.beginFill(0xffffff);
      errorMC.graphics.drawRect(0, 0, stage.stageWidth, stage.stageHeight);
      errorMC.graphics.endFill();

      var errorTxt:TextField = new TextField();
      errorTxt.multiline = true;
      errorTxt.width = stage.width;
      errorTxt.height = stage.height;
      errorTxt.selectable = true;
      addChild(errorMC);
      addChild(errorTxt);

      errorTxt.text = 'Error(s) Caught: \n' + msg;
    }
  }
}

Is this overkill or am I missing a “best practice” here?

Answer 1

You can just use FireBug to Debug and output from a SWF in the browser. Just Google for “firebug as3”, and you will see a ton of people are doing this.

You can also use something like De MonsterDebugger. It has a lot of great features. For an overview, check out Lee Brimlows De MonsterDebugger video from GoToAndLearn.