Xamarin Studio Android Face Detection

Question

我正在为Android开发Xamarin移动应用程序，我尝试使用Camera2类。 一切看起来都很好，但是这一行在转换类型上出现问题。它说(Java.Lang.Object -> Android.Hardware.Camera2.Params.Face[](这一行适用于Android Studio，但不适用于C#。

这是我在 Xamarin 上使用的代码。除了人脸识别，所有构建的请求都可以正常工作。https://github.com/xamarin/monodroid-samples/tree/master/android5.0/Camera2Basic

Face[] faces  = result.Get(CaptureResult.StatisticsFaces);

public class CameraCaptureListener : CameraCaptureSession.CaptureCallback
{
    public FaceTrainActivityFragment Owner { get; set; }
    public File File { get; set; }
    public override void OnCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result)
    {
        Process(result);
    }
    public override void OnCaptureProgressed(CameraCaptureSession session, CaptureRequest request, CaptureResult partialResult)
    {
        Process(partialResult);
    }
    private void Process(CaptureResult result)
    {
        switch (Owner.mState)
        {
            case FaceTrainActivityFragment.STATE_PREVIEW:
                {
                    if (result.Get(CaptureResult.StatisticsFaces) != null) {
                        //Face[] faces  = result.Get(CaptureResult.StatisticsFaces);
                        //Face[] faces  = (Face[])result.Get(CaptureResult.StatisticsFaces);
                    }
                    break;
                }
        }
    }
}

即使我使用硬强制转换到(Face[](进行编译，它也不允许我进行编译，它给了我相同的Java.Lang.Object错误。

    public void CreateCameraPreviewSession()
    {
        try
        {
            SurfaceTexture texture = mTextureView.SurfaceTexture;
            if (texture == null)
            {
                throw new IllegalStateException("texture is null");
            }
            if (null == mCameraDevice) {
                return;
            }

            // We configure the size of default buffer to be the size of camera preview we want.
            texture.SetDefaultBufferSize(mPreviewSize.Width, mPreviewSize.Height);
            // This is the output Surface we need to start preview.
            Surface surface = new Surface(texture);
            // We set up a CaptureRequest.Builder with the output Surface.
            mPreviewRequestBuilder = mCameraDevice.CreateCaptureRequest(CameraTemplate.Preview);
            mPreviewRequestBuilder.AddTarget(surface);
            // Here, we create a CameraCaptureSession for camera preview.
            List<Surface> surfaces = new List<Surface>();
            surfaces.Add(surface);
            //surfaces.Add(mImageReader.Surface);
            setFaceDetect(mPreviewRequestBuilder, mFaceDetectMode);
            mCameraDevice.CreateCaptureSession(surfaces, new CameraCaptureSessionCallback(this), null);
        }
        catch (CameraAccessException e)
        {
            e.PrintStackTrace();
        }

我在相机状态侦听器中调用创建相机预览会话，就像那样

public class CameraStateListener : CameraDevice.StateCallback
{
    public FaceTrainActivityFragment owner;
    public override void OnOpened(CameraDevice cameraDevice)
    {
        // This method is called when the camera is opened.  We start camera preview here.
        owner.mCameraOpenCloseLock.Release();
        owner.mCameraDevice = cameraDevice;
        owner.CreateCameraPreviewSession();
    }

Answer 1

它说(Java.Lang.Object -> Android.Hardware.Camera.Params.Face[](这一行适用于Android Studio，但不适用于C#。

从您收到的错误来看，您可能使用了错误的命名空间来Face。代替Android.Hardware.Camera.Params.Face，请使用Android.Hardware.Camera2.Params.Face。