下面是一个监控并显示flash运行帧数和内存占用情况的工具类（Flex也适用）。

package
{
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.geom.Rectangle;
    import flash.system.System;
    import flash.text.TextField;
    import flash.text.TextFieldAutoSize;
    import flash.text.TextFormat;
    import flash.utils.getTimer;
    
    public class Fps extends Sprite 
    {
        private var fps:TextField;  
        private var mem:TextField; 
        private var instance:Fps;  
        private var bitmapdata:BitmapData; 
        private var i:int = 0; 
        private var n:int = 10;  
        private var diagramTimer:int;  
        private var tfTimer:int;  
        private var skins:int = -1;  
        private var skinsChanged:int = 0;  
        private static const diagramHeight:uint = 40;  
        private static const diagramWidth:uint = 60;  
        private static const maxMemory:uint = 500000000; 
        public function Fps()
        {
            this.addEventListener(Event.ADDED_TO_STAGE,init);  
        }
        
        public function init(e:Event):void  
        {  
            var bitmap:Bitmap = null;  
            this.removeEventListener(Event.ADDED_TO_STAGE,init);  
            fps = new TextField();  
            mem = new TextField(); 
            if(instance == null) { 
                fps.defaultTextFormat = new TextFormat("Tahoma", 10, 16711680);  
                fps.autoSize = TextFieldAutoSize.LEFT; 
                fps.text = "FPS:" + Number(stage.frameRate).toFixed(2); 
                fps.x = -diagramWidth - 2; 
                addChild(fps); 
                
                mem.defaultTextFormat = new TextFormat("Tahoma", 10, 65280); 
                mem.autoSize = TextFieldAutoSize.LEFT;  
                mem.text = "MEM:" + byteToString(System.totalMemory); 
                mem.x = -diagramWidth - 2;  
                mem.y = fps.y + 10; 
                addChild(mem);  
                bitmapdata = new BitmapData(diagramWidth,diagramHeight,true,255); 
                bitmap = new Bitmap(bitmapdata); 
                bitmap.y = 24; 
                bitmap.x = -diagramWidth; 
                addChildAt(bitmap,0); 
                
                addEventListener(Event.ENTER_FRAME,onEnterFrame); 
                diagramTimer = getTimer(); 
                tfTimer = getTimer();  
            }   
        }  
        private function onEnterFrame(e:Event):void
        {   
            i++; 
            if(i >= n)   {   
                i = 0;  
                fps.text = "FPS: " + Number(1000 * n / (getTimer() - tfTimer)).toFixed(2); 
                tfTimer = getTimer();  
            } 
            var _loc_2:* = 1000 / (getTimer() - diagramTimer);  
            var _loc_3:* = _loc_2 > stage.frameRate ? (1) : (_loc_2 / stage.frameRate); 
            diagramTimer = getTimer(); 
            bitmapdata.scroll(1, 0); 
            bitmapdata.fillRect(new Rectangle(0, 0, 1, bitmapdata.height), 2852126720); 
            bitmapdata.setPixel32(0, diagramHeight * (1 - _loc_3), 4294901760);
            mem.text = "MEM: " + byteToString(System.totalMemory); 
            var ski:int = skins == 0 ? (0) : (skinsChanged / skins); 
            bitmapdata.setPixel32(0, diagramHeight * (1 - ski), 4294967295); 
            var meoryPer:Number = System.totalMemory / maxMemory;  
            bitmapdata.setPixel32(0, diagramHeight * (1 - meoryPer), 4278255360);  
        } 
        
        private function byteToString(byte:uint):String  
        { 
            var byteStr:String = null;  
            if (byte < 1024) 
            {
                byteStr = String(byte) + "b";  94.   }  
            else if (byte < 10240) 
            {    byteStr = Number(byte / 1024).toFixed(2) + "kb"; 
            }  else if (byte < 102400)  
            {  
                byteStr = Number(byte / 1024).toFixed(1) + "kb";  
            } 
            else if (byte < 1048576)    { 
                byteStr = Math.round(byte / 1024) + "kb";  
            }  
            else if (byte < 10485760) 
            { 
                byteStr = Number(byte / 1048576).toFixed(2) + "mb"; 
            } 
            else if (byte < 104857600) 
            { 
                byteStr = Number(byte / 1048576).toFixed(1) + "mb";  
            }  
            else
            {  
                byteStr = Math.round(byte / 1048576) + "mb";  
            } 
            return byteStr;  
        }  
        
    }
}

使用方法：

//增加帧数和内存检测
var fps:Fps = new Fps();
fps.x = 100;
fps.y = 20;
addChild(fps);