Creating an MXML based icon for the Halo LinkButton control in Flex 4

The following example shows how you can create an MXML-based icon for the Halo/MX LinkButton control in Flex 4 by creating a custom component using the <fx:Component/> tag and setting the className property.

Full code after the jump.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.

For more information on getting started with Flex 4 and Flash Builder 4, see the official Adobe Flex Team blog.

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/10/29/creating-an-mxml-based-icon-for-the-halo-linkbutton-control-in-flex-4/ -->
<s:Application name="Halo_LinkButton_icon_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/halo">
 
    <fx:Declarations>
        <fx:Component className="ico">
            <s:Graphic>
                <s:states>
                    <s:State name="up" />
                    <s:State name="over" />
                    <s:State name="down" />
                </s:states>
                <s:Ellipse  width="8" height="8">
                    <s:fill>
                        <s:SolidColor color="red" color.over="green" color.down="blue" />
                    </s:fill>
                </s:Ellipse>
            </s:Graphic>
        </fx:Component>
    </fx:Declarations>
 
    <mx:LinkButton id="lnkBtn"
            label="Halo LinkButton"
            icon="ico"
            horizontalCenter="0" verticalCenter="0" />
 
</s:Application>

You can also set the icon style in an external .CSS file or <Style/> block, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/10/29/creating-an-mxml-based-icon-for-the-halo-linkbutton-control-in-flex-4/ -->
<s:Application name="Halo_LinkButton_icon_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/halo">
 
    <fx:Style>
        @namespace s "library://ns.adobe.com/flex/spark";
        @namespace mx "library://ns.adobe.com/flex/halo";
 
        mx|LinkButton {
            icon: ClassReference("ico");
        }
    </fx:Style>
 
    <fx:Declarations>
        <fx:Component className="ico">
            <s:Graphic>
                <s:states>
                    <s:State name="up" />
                    <s:State name="over" />
                    <s:State name="down" />
                </s:states>
                <s:Ellipse  width="8" height="8">
                    <s:fill>
                        <s:SolidColor color="red" color.over="green" color.down="blue" />
                    </s:fill>
                </s:Ellipse>
            </s:Graphic>
        </fx:Component>
    </fx:Declarations>
 
    <mx:LinkButton id="lnkBtn"
            label="Halo LinkButton"
            horizontalCenter="0" verticalCenter="0" />
 
</s:Application>

Or you can set the icon style using ActionScript, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/10/29/creating-an-mxml-based-icon-for-the-halo-linkbutton-control-in-flex-4/ -->
<s:Application name="Halo_LinkButton_icon_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/halo">
    <s:controlBarContent>
        <s:Button id="btn"
                label="Set icon"
                click="btn_clickHandler(event);" />
    </s:controlBarContent>
 
    <fx:Script>
        <![CDATA[
            protected function btn_clickHandler(evt:MouseEvent):void {
                lnkBtn.setStyle("icon", ico);
            }
        ]]>
    </fx:Script>
 
    <fx:Declarations>
        <fx:Component className="ico">
            <s:Graphic>
                <s:states>
                    <s:State name="up" />
                    <s:State name="over" />
                    <s:State name="down" />
                </s:states>
                <s:Ellipse  width="8" height="8">
                    <s:fill>
                        <s:SolidColor color="red" color.over="green" color.down="blue" />
                    </s:fill>
                </s:Ellipse>
            </s:Graphic>
        </fx:Component>
    </fx:Declarations>
 
    <mx:LinkButton id="lnkBtn"
            label="Halo LinkButton"
            horizontalCenter="0" verticalCenter="0" />
 
</s:Application>

This entry is based on a beta version of the Flex 4 SDK and therefore is very likely to change as development of the Flex SDK continues. The API can (and will) change causing examples to possibly not compile in newer versions of the Flex 4 SDK.