buttonbar.mxml code:-


<?xml version="1.0"?>
<mx:ButtonBar xmlns:mx="http://www.adobe.com/2006/mxml" borderStyle="solid" horizontalGap="5">
        <mx:dataProvider>
            <mx:String>Submit</mx:String>
            <mx:String>Login</mx:String>
            <mx:String>Register</mx:String>            
        </mx:dataProvider>
</mx:ButtonBar>



mainapplication.mxml code:-


<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:CustComp="custocumponent.*">
    <CustComp:buttonbar/>
</mx:Application>