frameworks/projects/framework/asdoc/en_US/mx/controls/examples/CheckBoxExample.mxml

<?xml version="1.0"?>
<!--

  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

-->
<!-- Simple example to demonstrate the Halo CheckBox control -->
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx">

    <fx:Script>
        <![CDATA[
            import mx.controls.Alert;

            // This event handler adds and deletes items from the shopping cart.
            private function modifyCart():void {
                cartItems.text = "";

                if(milkCB.selected) {
                    cartItems.text += "milk" + "\n";
                }

                if(eggsCB.selected) {
                    cartItems.text += "eggs" + "\n";
                }

                if(breadCB.selected) { 
                    cartItems.text +="bread" + "\n";
                }
            }

           // This event handler opens the Halo Alert control.
           private function sendMessage():void {
                if(couponCB.selected) {
                    Alert.show("You will receive coupons.");
                } else {
                    Alert.show("You will not receive any coupons.");
                }
           }
        ]]>
    </fx:Script>

    <s:Panel title="Halo CheckBox Control Example" 
            width="75%" height="75%"
            horizontalCenter="0" verticalCenter="0">
        <s:HGroup left="10" right="10" top="10" bottom="10">
            <s:VGroup>
                <mx:CheckBox id="milkCB" label="milk" click="modifyCart();"/>
                <mx:CheckBox id="eggsCB" label="eggs" click="modifyCart();"/>
                <mx:CheckBox id="breadCB" label="bread" click="modifyCart();"/>
            </s:VGroup>

            <s:VGroup>
                <s:Label text="Items in my cart "/>
                <s:TextArea id="cartItems" width="300" height="50" verticalScrollPolicy="off"/>
                <!-- Event handler sendMessages() is used to handle event click -->
                <mx:CheckBox id="couponCB" label="Send me coupons for items in my cart"
                        click="sendMessage();" selected="true" color="blue"/>
            </s:VGroup>
        </s:HGroup>
    </s:Panel>

</s:Application>