Flex - Set focus on one component until user enters some value

I am trying to write the code for making a text input control in flex.

As the user enters the value in text input control and then if he removes the typed characters to make the text input blank, then I print error messag开发者_如何学Ce via StringValidator.

But I want the focus to be set on that text input only until the user enters anything. How can I achieve that ?

Thanks

Like David said, I would just check if the string is empty using the focusOut event. Of course, you still have to add the StringValidator logic to the code..

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication 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.events.FlexEvent;

            protected function focusOutHandler(event:FocusEvent):void
            {
                if (event.target.text == '')
                    event.target.setFocus();
            }

        ]]>
    </fx:Script>

    <s:TextInput id="myTextInput" focusOut="focusOutHandler(event)"/>

</s:WindowedApplication>

Try listening for a FocusEvent.FOCUS_OUT on the text field, then re-focus it if it's blank.