<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/03/08/setting-the-text-alignment-in-a-textarea-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white" viewSourceURL="srcview/index.html">

    <mx:Script>
        <![CDATA[
            import mx.events.ItemClickEvent;

            private function toggleButtonBar_itemClick(evt:ItemClickEvent):void {
                textArea.setStyle("textAlign", evt.label);
            }
        ]]>
    </mx:Script>

    <mx:Array id="arr">
        <mx:String>left</mx:String>
        <mx:String>center</mx:String>
        <mx:String>right</mx:String>
        <mx:String>justify</mx:String>
    </mx:Array>

    <mx:String id="lorem" source="lorem.txt" />

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="textAlign:">
                <mx:ToggleButtonBar id="toggleButtonBar"
                        dataProvider="{arr}"
                        selectedIndex="0"
                        itemClick="toggleButtonBar_itemClick(event);" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:TextArea id="textArea"
            text="{lorem}"
            textAlign="left"
            width="100%"
            height="100%" />

</mx:Application>