Flex中如何监测摄像头Camera对象活动以及状态事件与信息

flex中文案例:http://blog.minidx.com/2009/03/05/2228.html

<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" 
        layout="horizontal" 
        verticalAlign="middle" 
        backgroundColor="white"> 
  
    <mx:Script> 
        <![CDATA[ 
            import mx.controls.Alert; 
            import mx.utils.StringUtil; 
  
            private function videoDisplay_creationComplete():void { 
                var camera:Camera = Camera.getCamera(); 
                if (camera) { 
                    videoDisplay.attachCamera(camera); 
                    camera.addEventListener(ActivityEvent.ACTIVITY, camera_activity); 
                    camera.addEventListener(StatusEvent.STATUS, camera_status); 
                } else { 
                    Alert.show("You don't seem to have a camera."); 
                } 
            } 
  
            private function camera_activity(evt:ActivityEvent):void { 
                var str:String = "[{0}] activating:{1}\n"; 
                textArea.text += StringUtil.substitute(str, 
                                    evt.type, 
                                    evt.activating); 
            } 
  
            private function camera_status(evt:StatusEvent):void { 
                var str:String = "[{0}] code:'{1}', level:'{2}'\n"; 
                textArea.text += StringUtil.substitute(str, 
                                    evt.type, 
                                    evt.code, 
                                    evt.level); 
                switch (evt.code) { 
                    case "Camera.Muted": 
                        Alert.show("User denied access to camera."); 
                        break; 
                    case "Camera.Unmuted": 
                        Alert.show("User allowed access to camera."); 
                        break; 
                } 
            } 
        ]]> 
    </mx:Script> 
  
    <mx:VideoDisplay id="videoDisplay" 
            creationComplete="videoDisplay_creationComplete();" 
            width="160" 
            height="120" /> 
  
    <mx:TextArea id="textArea" 
            editable="false" 
            width="100%" 
            height="{videoDisplay.height}" 
            wordWrap="false" 
            verticalScrollPolicy="on" /> 
  
</mx:Application>