使ButtonBar的按钮字体显示描边效果

ButtonBar的按钮可以重写一下里面创建按钮的函数，达到修改按钮的效果

override protected function createNavItem(label:String, icon:Class=null):IFlexDisplayObject
{
    var _btn:Button = Button(super.createNavItem(label,icon));
    var _textField:TextField = _btn.mx_internal::getTextField();
    _textField.filters = myGlowFilter;
    return  _btn;
 }
   
   private var _defaltColor:uint=0x000000;
   private var defaultFilters:Array; 
   private function get myGlowFilter():Array
   {
    if( !defaultFilters )
    {
     var defaultGF:GlowFilter = new GlowFilter(_defaltColor,1,2,2,50,1,false,false);
     defaultFilters = new Array();
     defaultFilters.push( defaultGF );
    }
    return defaultFilters;
   }