Changing properties of several objects in Flex - apache-flex

Question

In my example below I have several objects. I want to change the label of all objects in one go, without calling each element by id. I know how to do this in HTML, but not in Flex.
// HTML
<div class="text" id="text1">SomeText</div>
<div class="text" id="text2">SomeText</div>
<div class="text" id="text3">SomeText</div>
// jQuery
$(".text").css("color", "#333333");
This is how I would usually set the color of 3 objects to grey in one line.
// Flex
<s:Button id="button1" label="Button 1"/>
<s:Button id="button2" label="Button 2"/>
<s:Button id="button3" label="Button 3"/>
// AS3
button1.label = 'Something else';
button2.label = 'Something else';
button3.label = 'Something else';
Is there any way I can change the labels of all 3 buttons with a single line of code similar to the jQuery example? Thanks in advance.

Answer 1

I'm pretty sure the answer is no, with a caveat.
Keep in mind that JQuery is a framework that hides the complexity of what it is doing. ( A lot of frameworks do that including the flex Framework ). In Flex, I can create a DataGrid in one line of code. However, there are thousands of lines of code, and multiple classes already written that allow me to do that. I suspect the same is true for a lot of JQuery functionality.
there is no reason you can't encapsulate that functionality to make the change and then call it with one line of code.

Answer 2

As #www.Flextras.com pointed out - you can write a class to do this.
I'd encourage you to consider an alternative approach however, as looping through the children looking for a specific property is quite slow. That said - it does make for an interesting coding challenge.
Here's a class & example that should acheive what you're after.
package com.mangofactory.util
{
import flash.display.DisplayObject;
import mx.core.UIComponent;
/**
* Utility class to set a given property of all matching children on a target.
* Named to act as an operator, rather than a class (hence no captial letter)
*
* eg., on(someTarget).of(SomeClass).someProperty = someValue;
* */
public class on
{
private var root:UIComponent;
private var requiredPropertyName:String;
private var requiredType:Class;
public function on(root:UIComponent)
{
this.root = root;
}
/**
* Returns a list of targets which match the defined criteria.
* Note - the root component is also evaluated
* */
private function get targets():void
{
var result:Array = [];
if (matches(root))
{
result.push(root);
}
for (var i:int = 0; i < root.numChildren; i++)
{
var child:DisplayObject = root.getChildAt(i);
if (matches(child))
result.push(child);
}
}
/**
* Returns true if the target param matches the defined criteria.
* If a propertyName has been given (by calling 'having') that is checked first.
* Otherwise, the type is checked against the value passed calling ('of')
* */
private function matches(target:Object):Boolean
{
if (requiredPropertyName && target.hasOwnProperty(requiredPropertyName))
return true;
if (requiredType && target is requiredType)
return true;
return false;
}
public function having(propertyName:String):PropertyCatcher
{
this.requiredPropertyName = propertyName;
}
public function setOnTargets(propertyName:*,value:*):void
{
for each (var matchedTarget:Object in targets)
{
if (matchedTarget.hasOwnProperty(propertyName))
matchedTarget[propertyName] = value;
}
}
public function of(type:Class):PropertyCatcher
{
this.requiredType = type;
}
}
}
import com.mangofactory.util.on;
import flash.utils.Proxy;
import flash.utils.flash_proxy;
use namespace flash_proxy;
dynamic class PropertyCatcher() extends Proxy
{
private var callbackTarget:on;
public function PropertyCatcher(callbackTarget:on)
{
this.callbackTarget = callbackTarget;
}
override flash_proxy function setProperty(name:*, value:*):void {
callbackTarget.setOnTargets(name,value);
}
}
And an example:
<?xml version="1.0" encoding="utf-8"?>
<mx:Canvas xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx">
<s:Button />
<s:Button />
<s:Button />
<mx:Canvas />
<fx:Script>
<![CDATA[
public function doTest():void
{
// Sets the label of all Buttons to "Hello World"
on(this).of(Button).label = "Hello World";
// Sets the visible property of all children which declare a "alpha" property to false.
on(this).having("alpha").visible = false;
}
]]>
</fx:Script>
</mx:Canvas>
Note - I haven't tested this, but in theory it should work.

Answer 3

I don't know of any selector of the css3/jquery type for flex. But a workaround will be to use an array of buttons instead of many buttons variables and then just iterate through all of them (button[i] instead of buttoni)