如何在 Xamarin.iOS 中获取照片的字节 []

Question

我正在 Xamarin.iOS 中开发摄影软件。 我正在使用 PHPhoto 类。

当我拍照时，我试图将其发送到网络。 我打算用字节 [] 发送它们。 我在哪里可以获取 DidFinishCapture 方法中的照片数据？ 当我开始调试启动时，我看到 PHPhotoLibrary.SharedPhotoLibrary.PerformChanges() 会自动将照片保存到照片库中。

如何按字节[]检索照片？ 我在 PhotoData 中找不到它。

我以为 LivePhotoCompanionMovieUrl 中有保存照片的路径，但这始终为空。

    public partial class PhotoCaptureDelegate : AVCapturePhotoCaptureDelegate
    {
        public override void DidFinishCapture(AVCapturePhotoOutput captureOutput, 
                                              AVCaptureResolvedPhotoSettings resolvedSettings, 
                                              NSError error)
        {
            PHPhotoLibrary.RequestAuthorization(status =>
            {
                if (status == PHAuthorizationStatus.Authorized)
                {
                    PHPhotoLibrary.SharedPhotoLibrary.PerformChanges(() =>
                    {
                        var creationRequest = PHAssetCreationRequest.CreationRequestForAsset();
                        creationRequest.AddResource(PHAssetResourceType.Photo, PhotoData, null);

                        var url = LivePhotoCompanionMovieUrl;
                        if (url != null)
                        {
                            var livePhotoCompanionMovieFileResourceOptions = new PAssetResourceCreationOptions
                            {
                                ShouldMoveFile = true
                            };
                            creationRequest.AddResource(PHAssetResourceType.PairedVideo, url, livePhotoCompanionMovieFileResourceOptions);
                        }
                    }, (success, err) =>
                    {
                        if (err != null)
                            Debug.WriteLine($"Error occurered while saving photo to photo library: {error.LocalizedDescription}");
                    });
                }
            });
        }
    }
}

Answer 1

如果要将照片转换为字节数组，可以使用Nuget的插件 Media.Plugin 来选择或拍照。

await CrossMedia.Current.Initialize();
    
    if (!CrossMedia.Current.IsCameraAvailable || !CrossMedia.Current.IsTakePhotoSupported)
    {
        DisplayAlert("No Camera", ":( No camera available.", "OK");
        return;
    }

    var file = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions
    {
        SaveToAlbum = true,
        Name = "test.jpg"
    });

    if (file == null)
        return;

然后先将其转换为Stream ，然后再将其转换为字节数组。

 Stream stream = file.GetStream();

public byte[] GetImageStreamAsBytes(Stream input)
{
  var buffer = new byte[16*1024];
  using (MemoryStream ms = new MemoryStream())
  {
    int read;
    while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
    {
                ms.Write(buffer, 0, read);
    }
      return ms.ToArray();
   }
}

现在你可以得到如下的字节数组

var imgDate = GetImageStreamAsBytes(stream);

更新

你可以使用 UIImagePickerController

 UIImagePickerController imagePicker;

并在需要拍照时调用以下几行

      imagePicker = new UIImagePickerController
        {
            SourceType = UIImagePickerControllerSourceType.Camera,
            MediaTypes = UIImagePickerController.AvailableMediaTypes(UIImagePickerControllerSourceType.Camera)
        };

        // Set event handlers
        imagePicker.FinishedPickingMedia += ImagePicker_FinishedPickingMedia; ;
        imagePicker.Canceled += ImagePicker_Canceled; ;

        // Present UIImagePickerController;
        this.PresentViewController(imagePicker, true, null);

        private void ImagePicker_Canceled(object sender, EventArgs e)
        {
            imagePicker.DismissModalViewController(true);
        }

        private void ImagePicker_FinishedPickingMedia(object sender, UIImagePickerMediaPickedEventArgs args)
        {
            UIImage image = args.EditedImage ?? args.OriginalImage;

            if (image != null)
            {
                // Convert UIImage to .NET Stream object
                NSData data;
                if (args.ReferenceUrl.PathExtension.Equals("PNG") || args.ReferenceUrl.PathExtension.Equals("png"))
                {
                    data = image.AsPNG();
                }
                else
                {
                    data = image.AsJPEG(1);
                }

                Stream stream = data.AsStream();

              
            }
            else
            {
               
            }
            imagePicker.DismissModalViewController(true);
        }

public byte[] GetImageStreamAsBytes(Stream input)
{
  var buffer = new byte[16*1024];
  using (MemoryStream ms = new MemoryStream())
  {
    int read;
    while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
    {
                ms.Write(buffer, 0, read);
    }
      return ms.ToArray();
   }
}

现在你可以得到如下的字节数组

var imgDate = GetImageStreamAsBytes(stream);