Flex:在PANEL的title上加一个button[转]

//转自：http://www.cnblogs.com/GFantasy/archive/2010/03/05/1678917.html
package{
    import mx.containers.Panel;
    import mx.controls.Button;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.display.DisplayObject;
    import mx.effects.Resize;
    import mx.controls.Alert;
    import mx.controls.Label;
 
    [Event(name="restore")]
    [Event(name="maximize")]
 
    public class FlexPanel extends Panel{
        private var state:int = 0;
             
        private var restoreBtn: Button;
        private var minBtn: Button;
        private var closeBtn: Button;
        
        [Embed("../assets/minICON.png")] // 这里我自定义了按钮外观
        private var minIcon:Class;
        [Embed("../assets/minOverICON.png")]
        private var minOverIcon:Class;
        
        [Embed("../assets/restoreICON.png")]
        private var restoreIcon:Class;
        [Embed("../assets/restoreOverICON.png")]
        private var restoreOverIcon:Class;
        
        [Embed("../assets/closeICON.png")]
        private var closeIcon:Class;
        [Embed("../assets/closeOverICON.png")]
        private var closeOverIcon:Class;
        
        private var resize: Resize;    
        private var effectTime: Number = 400;
          
        private static var _instance: FlexPanel;
        
        public function FlexPanel(){
            super();
            _instance = this; 
        }
        
        public override function initialize():void{
            super.initialize();
            this.maxHeight = this.height;
            initEffect();
        }
        
        private function setState(state:int):void{
            this.state=state;
            if (state==0){
                this.dispatchEvent(new Event('restore'));
            } else {
                this.dispatchEvent(new Event('maximize'));
            }
        }
        /* ************************************************* */
        protected override function createChildren(): void {
            super.createChildren();
           
            this.titleBar.addEventListener(MouseEvent.MOUSE_DOWN, doDrag);
            this.titleBar.addEventListener(MouseEvent.MOUSE_UP, doDrop);
           
            restoreBtn = new Button();
            restoreBtn.addEventListener("click",doRestore);       
            restoreBtn.setStyle("overIcon",restoreOverIcon);
            restoreBtn.setStyle("downIcon",restoreIcon);
            restoreBtn.setStyle("upIcon",restoreIcon);       
            restoreBtn.visible=false;
            rawChildren.addChild(restoreBtn); 
           
            minBtn = new Button();
            minBtn.addEventListener("click",doMin);
            minBtn.setStyle("overIcon",minOverIcon);
            minBtn.setStyle("downIcon",minIcon);
            minBtn.setStyle("upIcon",minIcon);
            minBtn.visible = true;
            rawChildren.addChild(minBtn);
           
            closeBtn = new Button();
            closeBtn.addEventListener("click",doClose);
            closeBtn.setStyle("overIcon",closeOverIcon);
            closeBtn.setStyle("downIcon",closeIcon);
            closeBtn.setStyle("upIcon",closeIcon);
            closeBtn.visible = true;
            rawChildren.addChild(closeBtn);       
           
        }
        /* ************************************************** */
        protected override function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void{
            super.updateDisplayList(unscaledWidth, unscaledHeight);           
        }
        
        private function doMin(event:Event):void{
            setState(1);
            minBtn.visible= false;
            restoreBtn.visible= true;
            minEffect();
            //Alert.show(this.verticalScrollBar.toString());
        }
         
        private function doRestore(event:Event) :void{
            setState(0);
            minBtn.visible= true;
            restoreBtn.visible= false;
            restoreEffect();
        }
        
        private function doClose(event:Event) :void{
            this.visible = false;
            this.parent.removeChild(this);
        }
        
        private function doDrag(event:Event):void{
            this.startDrag();       
        }
        
        private function doDrop(event:Event):void{
            this.stopDrag();       
        }
        /* ********************************************************************************* */
        protected override function layoutChrome(unscaledWidth: Number, unscaledHeight:Number):void {
            super.layoutChrome(unscaledWidth, unscaledHeight);
           
            var margin:int = 0;
            var pixelsFromTop:int = 6;
            var pixelsFromRight:int = 12;
            var buttonWidth:int = 18;
            var buttonHeight:int = 17;
            var distance:int = 7;
            var x:Number = this.width - buttonWidth*2 - distance - pixelsFromRight;
            var y:Number = pixelsFromTop;
           
            restoreBtn.setActualSize(buttonWidth, buttonHeight);
            restoreBtn.move(x,y);
           
            minBtn.setActualSize(buttonWidth, buttonHeight);
            minBtn.move(x,y);
           
            closeBtn.setActualSize(buttonWidth, buttonHeight);
            closeBtn.move(this.width - buttonWidth - pixelsFromRight,y);
           
        }
        /* ********************************************************************************* */
        private function initEffect():void{       
            resize = new Resize(_instance);
            resize.heightTo = this.titleBar.height;
            resize.duration = effectTime;
        }
        
        private function minEffect():void{
            resize.heightTo = this.titleBar.height;
            resize.end();
            resize.play();
        }
        
        private function restoreEffect():void{
            resize.heightTo = this.maxHeight;
            resize.end();
            resize.play();
        }
    }
}