Flex中如何让TextInput被选中文本保持选中状态而不管控件是否获得焦点的例子

下面是完整代码(或点击这里察看)：

下面是main.mxml：

<?xml version="1.0" encoding="utf-8"?> 
<!-- http://blog.flexexamples.com/2009/04/30/always-displaying-the-selected-text-in-a-textinput-in-flex/ --> 
<mx:Application name="TextInput_getTextField_alwaysShowSelection_test" 
        xmlns:mx="http://www.adobe.com/2006/mxml" 
        layout="vertical" 
        verticalAlign="middle" 
        backgroundColor="white"> 
  
    <mx:Script> 
        <![CDATA[ 
            import mx.core.UITextField; 
            import mx.controls.TextInput; 
  
            private function init(evt:Event):void { 
                var ti:TextInput = evt.currentTarget as TextInput; 
                var tf:UITextField = ti.mx_internal::getTextField(); 
                tf.alwaysShowSelection = true; 
            } 
        ]]> 
    </mx:Script> 
  
    <mx:TextInput id="textInput" 
            text="The quick brown fox jumps over the lazy dog." 
            selectionBeginIndex="4" selectionEndIndex="9" 
            initialize="init(event);" /> 
    <mx:Button label="Submit" /> 
  
</mx:Application>