用as3调用摄像头

用as3调用摄像头，代码如下：

package {
    import flash.display.Sprite;
    import flash.text.*;
    import flash.media.Camera;
    import flash.events.StatusEvent;
    import flash.events.ActivityEvent;
    import flash.media.Video;

    public class CameraEx extends Sprite
    {
        private var label:TextField;
        private var camera:Camera;
        
        public function CameraEx()
        {
            label=addLabel("CameraEx");
            
            camera=Camera.getCamera();
            
            if(camera!=null){
                camera.addEventListener(StatusEvent.STATUS,statusHandler);
                camera.addEventListener(ActivityEvent.ACTIVITY,activityHandler);
                
                var video:Video=new Video(200,200);
                video.attachCamera(camera);
                addChild(video);
                video.x=20;
                video.y=20;
            }
            else{
                label.text="不能使用";
            }
        }
        
        private function statusHandler(evt:StatusEvent):void{
            if(camera.muted) label.text="不能使用";
        }
        
        private function activityHandler(evt:ActivityEvent):void{
            if(evt.activating){
                label.text="检测开始";
            }
            else{
                label.text="检测停止";
            }
        }
        
        private function addLabel(text:String):TextField{
            var label:TextField=new TextField();
            label.autoSize=TextFieldAutoSize.LEFT;
            label.text=text;
            addChild(label);
            return label;
        }
    }
}