//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();

        }

    }

}