Creating a toggleable LinkButton control in Flex

The following example shows how you can create a toggleable Flex LinkButton control by extending the mx.skins.halo.LinkButtonSkin and adding custom “selectedUpSkin”, “selectedOverSkin”, “selectedDownSkin”, and “selectedDisabledSkin” skin states.

Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/06/creating-a-toggleable-linkbutton-control-in-flex/ -->
<mx:Application name="LinkButton_toggle_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="toggle:">
                <mx:CheckBox id="toggleCheckBox" />
            </mx:FormItem>
            <mx:FormItem label="selected:">
                <mx:CheckBox id="selectedCheckBox"
                        selected="{linkButton.selected}" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:LinkButton id="linkButton"
            label="LinkButton"
            toggle="{toggleCheckBox.selected}"
            selected="{selectedCheckBox.selected}"
            skin="skins.ToggleLinkButtonSkin" />

</mx:Application>

skins/ToggleLinkButtonSkin.as

/**
 * http://blog.flexexamples.com/2008/09/06/creating-a-toggleable-linkbutton-control-in-flex/
 */
package {
    import mx.skins.halo.LinkButtonSkin;

    public class ToggleLinkButtonSkin extends LinkButtonSkin {
        public function ToggleLinkButtonSkin() {
            super();
        }

        override protected function updateDisplayList(w:Number, h:Number):void {
            super.updateDisplayList(w, h);

            var cornerRadius:Number = getStyle("cornerRadius");
            var rollOverColor:uint = getStyle("rollOverColor");
            var selectionColor:uint = getStyle("selectionColor");

            graphics.clear();

            switch (name) {
                case "upSkin":
                    // Draw invisible shape so we have a hit area.
                    drawRoundRect(
                        0, 0, w, h, cornerRadius,
                        0, 0);
                    break;

                case "selectedUpSkin":
                case "selectedOverSkin":
                case "overSkin":
                    drawRoundRect(
                        0, 0, w, h, cornerRadius,
                        rollOverColor, 1);
                    break;

                case "selectedDownSkin":
                case "downSkin":
                    drawRoundRect(
                        0, 0, w, h, cornerRadius,
                        selectionColor, 1);
                    break;

                case "selectedDisabledSkin":
                case "disabledSkin":
                    // Draw invisible shape so we have a hit area.
                    drawRoundRect(
                        0, 0, w, h, cornerRadius,
                        0, 0);
                    break;
            }
        }
    }
}

View source is enabled in the following example.

You can also set the LinkButton control’s skin style in an external .CSS file or <mx:Style /> block, as seen in the following example:

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/06/creating-a-toggleable-linkbutton-control-in-flex/ -->
<mx:Application name="LinkButton_toggle_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Style>
        LinkButton {
            skin: ClassReference("skins.ToggleLinkButtonSkin");
        }
    </mx:Style>

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="toggle:">
                <mx:CheckBox id="toggleCheckBox" />
            </mx:FormItem>
            <mx:FormItem label="selected:">
                <mx:CheckBox id="selectedCheckBox"
                        selected="{linkButton.selected}" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:LinkButton id="linkButton"
            label="LinkButton"
            toggle="{toggleCheckBox.selected}"
            selected="{selectedCheckBox.selected}" />

</mx:Application>

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

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/06/creating-a-toggleable-linkbutton-control-in-flex/ -->
<mx:Application name="LinkButton_toggle_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import skins.ToggleLinkButtonSkin;

            private function init():void {
                linkButton.setStyle("skin", ToggleLinkButtonSkin);
            }
        ]]>
    </mx:Script>

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="toggle:">
                <mx:CheckBox id="toggleCheckBox" />
            </mx:FormItem>
            <mx:FormItem label="selected:">
                <mx:CheckBox id="selectedCheckBox"
                        selected="{linkButton.selected}" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:LinkButton id="linkButton"
            label="LinkButton"
            toggle="{toggleCheckBox.selected}"
            selected="{selectedCheckBox.selected}"
            initialize="init();" />

</mx:Application>

Due to popular demand, here is the “same” example in a more ActionScript friendly format:

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/06/creating-a-toggleable-linkbutton-control-in-flex/ -->
<mx:Application name="LinkButton_toggle_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        initialize="init();">

    <mx:Script>
        <![CDATA[
            import skins.ToggleLinkButtonSkin;

            import mx.containers.ApplicationControlBar;
            import mx.containers.Form;
            import mx.containers.FormItem;
            import mx.controls.CheckBox;
            import mx.controls.LinkButton;

            private var toggleCheckBox:CheckBox;
            private var selectedCheckBox:CheckBox;
            private var linkButton:LinkButton;

            private function init():void {
                toggleCheckBox = new CheckBox();
                toggleCheckBox.addEventListener(Event.CHANGE,
                            toggleCheckBox_change);

                selectedCheckBox = new CheckBox();
                selectedCheckBox.addEventListener(Event.CHANGE,
                            selectedCheckBox_change);

                var formItem1:FormItem = new FormItem();
                formItem1.label = "toggle:";
                formItem1.addChild(toggleCheckBox);

                var formItem2:FormItem = new FormItem();
                formItem2.label = "selected:";
                formItem2.addChild(selectedCheckBox);

                var form:Form = new Form();
                form.styleName = "plain";
                form.addChild(formItem1);
                form.addChild(formItem2);

                var appControlBar:ApplicationControlBar;
                appControlBar = new ApplicationControlBar();
                appControlBar.dock = true;
                appControlBar.addChild(form);
                addChildAt(appControlBar, 0);

                linkButton = new LinkButton();
                linkButton.label = "LinkButton";
                linkButton.setStyle("skin", ToggleLinkButtonSkin);
                linkButton.addEventListener(Event.CHANGE,
                            linkButton_change);
                addChild(linkButton);
            }

            private function toggleCheckBox_change(evt:Event):void {
                linkButton.toggle = toggleCheckBox.selected;
            }

            private function selectedCheckBox_change(evt:Event):void {
                linkButton.selected = selectedCheckBox.selected;
            }

            private function linkButton_change(evt:Event):void {
                selectedCheckBox.selected = linkButton.selected;
            }
        ]]>
    </mx:Script>

</mx:Application>