Noob Flash

Unfortunately, MySQL does not support a subquery until MySQL 5.0. So if you tried to use the following code:

SELECT username FROM users WHERE user_id IN (SELECT user_id FROM admins);

you would get errors. Fortunately, I have figured out a nice little work around for this problem. Using php, you can use the following code to perform a subquery type request in MySQL 4.0.

$sql = "SELECT user_id FROM admins";
$rs = mysql_query($sql);
$adminuserids = array();
while ($ra = mysql_fetch_array($rs)){
$adminuserids[] = $ra[’user_id’];
}

# Our sql with “sub query”
$sql = “SELECT username FROM users WHERE user_id IN ($adminuserids)”;

That should take care of your MySQL 4.0 subquery needs.

Memory management code directly from the man at gskinner.com.
import flash.system.System;
import flash.net.navigateToURL;
import flash.net.URLRequest;
...
// check our memory every 1 second:
var checkMemoryIntervalID:uint = setInterval(checkMemoryUsage,1000);
...
var showWarning:Boolean = true;
var warningMemory:uint = 1000*1000*500;
var abortMemory:uint = 1000*1000*625;
...
function checkMemoryUsage() {
if (System.totalMemory > warningMemory && showWarning) {
// show an error to the user warning them that we're running out of memory and might quit
// try to free up memory if possible
showWarning = false; // so we don't show an error every second
} else if (System.totalMemory > abortMemory) {
// save current user data to an LSO for recovery later?
abort();
}
}
function abort() {
// send the user to a page explaining what happpened:
navigateToURL(new URLRequest("memoryError.html"));
}

You can find other system management tips at gskinner.com

In the process of creating an image gallery in AS3, I ran across this interesting error.

1118: Implicit coercion of a value with static type flash.display:DisplayObject to a possibly unrelated type flash.display:MovieClip.

Incorrect Code:

public class ImageGallery extends Component {
private var ldrData:URLLoader;
private var count:uint;
var holder:MovieClip;
var myMask:MovieClip;
public function ImageGallery() {
count = 0;
myMask = new MovieClip();
holder = new MovieClip();
addChild(holder);
holder.x = 50;
holder.y = 0;
myMask = addChild(new mask_mc());
holder.cacheAsBitmap = true;
myMask.cacheAsBitmap = true;
holder.mask = myMask;
if (this.stage != null) {
//Master.SetParameter("ModelId","100")
this.Initialize();
}
}
...
}

The fix for this error was simple. When declaring myMask = addChild(new mask_mc()), you can cast your variable using “as MovieClip” to fix the problem.

Corrected Code:

public class ImageGallery extends Component {
private var ldrData:URLLoader;
private var count:uint;
var holder:MovieClip;
var myMask:MovieClip;
public function ImageGallery() {
count = 0;
myMask = new MovieClip();
holder = new MovieClip();
addChild(holder);
holder.x = 50;
holder.y = 0;
myMask = addChild(new mask_mc()) as MovieClip;
holder.cacheAsBitmap = true;
myMask.cacheAsBitmap = true;
holder.mask = myMask;
if (this.stage != null) {
//Master.SetParameter("ModelId","100")
this.Initialize();
}
...
}

In ActionScript 3.0, the frame event model has been changed from the ActionScript 2.0 version quite a bit. In ActionScript 2.0, if you wanted to perform a task every time you entered a frame, you would type

onEnterFrame = function(){
trace("Do Something");
}

In ActionScript 3.0, you must use an event listener format to perform a frame event. For example…

addEventListener(Event.ENTER_FRAME,myFunction);
function myFunction(event:Event) {
trace("Do Something");
}

It’s a little more complicated than the old way, but ActionScript 3.0 opens up a whole new world of programming possibilities.

Adobe Flash CS3 Professional includes many great new features, including the ActionScript 3.0 programming language and the ActionScript 3.0 FLA file format. This article is a summary of notes and reflections as the author migrated to using ActionScript 3.0. The article also provides solutions that address these topics:

* Changes to handling movie clips
* Changes to loading data, content, and symbols
* Changes to building object classes in ActionScript 3.0

View The Article [adobe.com]