The following example shows how you can detect when the source property has changed on a Flex Image control using the sourceChanged event.
Full code after the jump.
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/06/27/detecting-when-the-source-changes-on-an-image-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
private function init():void {
img.addEventListener("sourceChanged", image_sourceChanged);
}
private function image_sourceChanged(evt:Event):void {
Alert.show(evt.toString(), evt.type);
}
]]>
</mx:Script>
<mx:ApplicationControlBar dock="true">
<mx:Button label="Flash"
click="img.source = 'assets/fl_appicon.jpg';" />
<mx:Button label="Flash Player"
click="img.source = 'assets/fl_player_appicon.jpg';" />
<mx:Button label="Flex"
click="img.source = 'assets/fx_appicon.jpg';" />
</mx:ApplicationControlBar>
<mx:Image id="img"
source="assets/fx_appicon.jpg"
initialize="init();"
width="100"
height="100" />
</mx:Application>
View source is enabled in the following example.
Due to popular demand, here is the “same” example in a more ActionScript friendly format:
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/06/27/detecting-when-the-source-changes-on-an-image-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white"
initialize="init();">
<mx:Script>
<![CDATA[
import mx.containers.ApplicationControlBar;
import mx.controls.Alert;
import mx.controls.Button;
import mx.controls.Image;
private var button1:Button;
private var button2:Button;
private var button3:Button;
private var img:Image;
private function init():void {
button1 = new Button();
button1.label = "Flash";
button1.addEventListener(MouseEvent.CLICK, function():void {
img.source = "assets/fl_appicon.jpg";
});
button2 = new Button();
button2.label = "Flash Player";
button2.addEventListener(MouseEvent.CLICK, function():void {
img.source = "assets/fl_player_appicon.jpg";
});
button3 = new Button();
button3.label = "Flex";
button3.addEventListener(MouseEvent.CLICK, function():void {
img.source = "assets/fx_appicon.jpg";
});
var appControlBar:ApplicationControlBar = new ApplicationControlBar();
appControlBar.dock = true;
appControlBar.addChild(button1);
appControlBar.addChild(button2);
appControlBar.addChild(button3);
Application.application.addChildAt(appControlBar, 0);
img = new Image();
img.source = "assets/fx_appicon.jpg";
img.width = 100;
img.height = 100;
img.addEventListener("sourceChanged", image_sourceChanged);
addChild(img);
}
private function image_sourceChanged(evt:Event):void {
Alert.show(evt.toString(), evt.type);
}
]]>
</mx:Script>
</mx:Application>





Thanks for the tip. I could not find any documentation on the “sourceChanged” Event in the Flex help and there doesn’t seem to be any popup hints for this event when coding the component in Flex. Any ideas?
Brendan,
There are several “undocumented” events in the Flex API. These events weren’t really meant for public use, but they can be useful in certain circumstances.
Peter
Do you know if there is a way to force the image to redraw? I’m very new to flex, but it looks as though the image is redrawn any time source is set, except in the case where I need it to.
Any help is appreciated. Thanks in advance.
Barry
Barry,
I’m not sure, but does calling
img.validateNow();help?Peter