SurfaceView sView;
        ISurfaceHolder surfaceHolder;

 protected override void OnCreate(Bundle bundle)
        {

            base.OnCreate(bundle);
            RequestWindowFeature(WindowFeatures.NoTitle);
            Window.SetFlags(WindowManagerFlags.Fullscreen, WindowManagerFlags.Fullscreen);
            SetContentView(Resource.Layout.layoutCameraMain);
            // Create your application here
            ////获取ip地址
            ipname = this.Intent.GetStringExtra("ipname");
            //获取屏幕分辨率
            DisplayMetrics dm = new DisplayMetrics();
            Display display = WindowManager.DefaultDisplay;
            display.GetMetrics(dm);
            //screenWidth = dm.WidthPixels;
            //screenHeight = dm.HeightPixels;

            screenWidth = display.Width;
            screenHeight = display.Height;
            sView = FindViewById<SurfaceView>(Resource.Id.sView);//获取界面中的surface
            surfaceHolder = sView.Holder;//获得SurfaceView的SurfaceHolder;

            ISurfaceHolderCallback ish = new SurfaceHolderCallBack(this);
            surfaceHolder.AddCallback(ish);
            // 设置该SurfaceView自己不维护缓冲 
            surfaceHolder.SetType(SurfaceType.PushBuffers);
 }

private void InintCamera()
        {
            if (!isPreview)
            {
                camera = Camera.Open();
            }
            if (camera != null && !isPreview)
            {
                try
                {
                    Camera.Parameters parameters = camera.GetParameters();
                    parameters.SetPreviewSize(screenWidth, screenHeight);//设置大小
                    //parameters.setPreviewFpsRange(20, 30);                    // 每秒显示20~30帧 
                    parameters.PictureFormat = Android.Graphics.ImageFormatType.Nv21;/// 设置图片格式  
                    parameters.SetPictureSize(screenWidth, screenHeight);
                    //parameters.Set("orientation", "portrait");
                    //parameters.SetRotation(90);//旋转90度
                    parameters.PreviewFrameRate = 30;    // 每秒显示30帧 
                    camera.SetPreviewDisplay(surfaceHolder); // 通过SurfaceView显示取景画
                    camera.SetDisplayOrientation(90);//旋转90度
                    //camera.SetPreviewCallback(new StreamIt(ipname, camera));
                    camera.SetParameters(parameters);
                    camera.StartPreview();                                   // 开始预览    

                    camera.AutoFocus(null);                                  // 自动对焦
                }
                catch (Exception e)
                {
                    string error = e.StackTrace;
                }
            }
        }
        class MyThread : Java.Lang.Thread
        {

        }
        /// <summary>
        /// 试映回掉
        /// </summary>
        class StreamIt : Camera.IPreviewCallback
        {
            string ipname;
            Camera camera;
            public StreamIt(string ipname, Camera camera)
                : base()
            {
                this.camera = camera;
                this.ipname = ipname;
            }
            public void OnPreviewFrame(byte[] data, Camera camera)
            {
                Camera.Size size = camera.GetParameters().PreviewSize;
                try
                {
                    //调用image.compressToJpeg（）将YUV格式图像数据data转为jpg格式
                    Android.Graphics.YuvImage image = new Android.Graphics.YuvImage(data, Android.Graphics.ImageFormatType.Nv21, size.Width, size.Height, null);
                    if (image != null)
                    {
                        MemoryStream mstream = new MemoryStream();
                        image.CompressToJpeg(new Android.Graphics.Rect(0, 0, size.Width, size.Height), 80, mstream);
                        mstream.Flush();
                        //启用线程把图片发送出去

                    }
                }
                catch (Exception ex)
                {
                    Log.Error("转换图片时出错", ex.Message);
                }
                //throw new NotImplementedException();
            }

            public void Dispose()
            {
                throw new NotImplementedException();
            }

            public IntPtr Handle
            {
                get { return camera.Handle; }
            }
        }
        /// <summary>
        /// 定义SurfaceHolder回掉
        /// </summary>

        public class SurfaceHolderCallBack : ISurfaceHolderCallback
        {
            ActivityCameraMain _main;
            public SurfaceHolderCallBack(ActivityCameraMain main)
                : base()
            {
                _main = main;
            }
            public void SurfaceChanged(ISurfaceHolder holder, Android.Graphics.Format format, int width, int height)
            {
                //throw new NotImplementedException();
            }

            public void SurfaceCreated(ISurfaceHolder holder)
            {
                //throw new NotImplementedException();
                _main.InintCamera();
            }

            public void SurfaceDestroyed(ISurfaceHolder holder)
            {
                //throw new NotImplementedException();
                if (_main.camera != null)
                {
                    if (_main.isPreview)
                    {
                        _main.camera.StopPreview();
                        _main.camera.Release();
                        _main.camera = null;
                    }
                    //System.exit(0);
                }

            }
            void IDisposable.Dispose()
            {
                ;
            }

            IntPtr IJavaObject.Handle
            {
                get { return ((View)_main.sView).Handle; }
            }
        }