RequestContentEditingInput completionHandler 不运行

Question

我有一个应用程序，我需要从 phone 中选择图像并按照用户选择它们的顺序显示它们（我需要按选择顺序排列的 img，而不是 "most recent edited" 这就是我不使用 UIImagePickerController 的原因）

为此，我有一个页面显示最新的 50 张图片，并且可以加载更多图片。

我正在使用下面的代码获取图像路径和方向。

我的问题：CompletionHandler（在 RequestContentEditingInput 中）只会运行 17 次... 我可以看到每个图像都调用了 RequestContentEditingInput（在此 phone 138 次）

我尝试等待，但没有任何反应。

当我的图片少于 17 张时，代码会按预期工作...

我试图在 CompletionHandler 代码中实现一个 SemaphoreSlim 锁来控制我一次只能处理 10 个图像，但最终结果是相同的或根本没有处理图像。

UpdateInfo：似乎是所有未处理的LivePhotos。

有人知道这里发生了什么吗？

有修复的想法吗？

还有其他方法可以获得所有图像路径和方向吗？

或者让用户从 phone 中选择图像并获取用户选择它们的顺序的完全不同的解决方案？

    public class GalleryHelper : IGalleryHelper
    {
        private List<(string, string, string)> _retval;
        private nint _numberofImg = 0;
        private nint _currentImg = 0;

        public List<(string, string, string)> GetAllImgFromGallery()
        {
            _retval = new List<(string, string, string)>();
            _currentImg = 0;
            GetAllImg();
            return _retval;
        }

        private void GetAllImg()
        {
            var fetchOptions = new PHFetchOptions();

            PHFetchResult allPhotos = PHAsset.FetchAssets(PHAssetMediaType.Image, fetchOptions);
            _numberofImg = allPhotos.Count;

            Debug.WriteLine("Total img no + " + _numberofImg);

            for (nint i = 0; i < allPhotos.Count; i++)
            {
                Debug.WriteLine("Starting " + i);
                (allPhotos[i] as PHAsset).RequestContentEditingInput(new PHContentEditingInputRequestOptions(), CompletionHandler);
            }
        }

        private void CompletionHandler(PHContentEditingInput contentEditingInput, NSDictionary requestStatusInfo)
        {
            Debug.WriteLine("Starting CompletionHandler " + (1 + _currentImg));
            var path = contentEditingInput.FullSizeImageUrl.Path;
            if (path != null)
            {
                var orientation = contentEditingInput.FullSizeImageOrientation;

                switch (orientation)
                {
                    case CIImageOrientation.TopLeft:
                        //Standard position
                        _retval.Add((path, null, "0"));
                        break;

                    case CIImageOrientation.LeftBottom:
                        //Rotate 90 degrees clockwise
                        _retval.Add((path, null, "-90"));
                        break;

                    case CIImageOrientation.RightTop:
                        //Rotate 90 degrees counterclockwise
                        _retval.Add((path, null, "90"));
                        break;

                    case CIImageOrientation.BottomRight:
                        //Rotate 180 degrees
                        _retval.Add((path, null, "180"));
                        break;

                    case CIImageOrientation.BottomLeft:
                        //Mirror image rotated 180 degrees
                        _retval.Add((path, null, "180"));
                        break;

                    case CIImageOrientation.TopRight:
                        //Mirror image
                        _retval.Add((path, null, "0"));
                        break;

                    case CIImageOrientation.LeftTop:
                        //Mirror image rotate 90 degrees clockwise
                        _retval.Add((path, null, "-90"));
                        break;

                    case CIImageOrientation.RightBottom:
                        //Mirror image rotate 90 degrees counterclockwise.
                        _retval.Add((path, null, "90"));
                        break;

                    default:
                        _retval.Add((path, null, "0"));
                        break;
                }
            }
            _currentImg++;
            Debug.WriteLine("Images done " + _currentImg);
            MessagingCenter.Send((App)Xamarin.Forms.Application.Current, "ImagesReady", _retval);

        }
    }

从我的调试输出粘贴到运行:

[0:] Total img no + 138
[0:] Starting 0
[0:] Starting 1
(...)
[0:] Starting 137
[0:] Starting CompletionHandler 1
[0:] Images done 1
[0:] Starting CompletionHandler 2
[0:] Images done 2
[0:] Starting CompletionHandler 3
[0:] Images done 3
(...)
[0:] Starting CompletionHandler 15
[0:] Images done 15
[0:] Starting CompletionHandler 16
[0:] Images done 16
[0:] Starting CompletionHandler 17
[0:] Images done 17
Thread started: #17
Thread finished: #15
The thread 0xf has exited with code 0 (0x0).
Thread finished: #3

Answer 1

如果以后有人遇到同样的问题。使用 PHImageManager.DefaultManager.RequestImageData() 而不是 PHAsset.RequestContentEditingInput()，因为如果您要求它处理大量图像，它不会崩溃。

我会这样做：

    var fetchOptions = new PHFetchOptions();
    PHFetchResult allPhotos = PHAsset.FetchAssets(PHAssetMediaType.Image, fetchOptions);
    _numberofImg = allPhotos.Count;
    Debug.WriteLine("Total img no + " + _numberofImg);
    await Task.Yield();
    await Task.Run(() => ImgProcess(allPhotos));
    return true;

private void ImgProcess(PHFetchResult allPhotos)
{
    //await Task.Run(() =>
    //{
        for (nint i = 0; i < allPhotos.Count; i++)
        {
            Debug.WriteLine("Starting " + i);
            var phasset = allPhotos[i] as PHAsset;
            var options = new PHImageRequestOptions()
            {
                Synchronous = true,
                NetworkAccessAllowed = false,
                DeliveryMode = PHImageRequestOptionsDeliveryMode.FastFormat
            };
            PHImageManager.DefaultManager.RequestImageData(phasset, options, ComplManager);
        }
    //});
    //return;
}

即使当图像数量超过 300 张时此解决方案仍然存在问题...

RequestContentEditingInput completionHandler 不运行

RequestContentEditingInput completionHandler do not run

c#

xamarin.ios

xamarin.forms

photosframework

RequestContentEditingInput completionHandler 不 运行

RequestContentEditingInput completionHandler do not run

c#

xamarin.ios

xamarin.forms

photosframework

RequestContentEditingInput completionHandler 不运行