uno-platform - GetFileFromApplicationUriAsync、CopyAsync、AsStreamForRead 未在 Uno 平台中实现。解决方法？

Question

我尝试使用以下方法，但它们在 Uno (Android) 中都显示为未实现。我能做什么？

是否有任何 Xamarin.Essentials 替代品？

或其他NuGet 包？

或者我应该在每个平台上使用本地实现吗？

是否有可能直接在 Uno 中实现？

var pdfFile = StorageFile.GetFileFromApplicationUriAsync(..);
pdfFile.CopyAsync(..);
(await pdfFile.OpenReadAsync()).AsStreamForRead(); // AsStreamForRead() not implemented

我使用的是 Uno.UI v1.45.0。

Answer 1

作为大卫·奥利弗 pointed out in his answer ,

Uno hasn't implemented most of the Windows.StorageFile APIs, as for the most part there are alternatives available in System.IO, which will work cross-platform.

所以...

1. 要从应用程序包中打开文件，我们可以将其构建操作设置为Embedded Resource 而不是Content。我们可以使用以下代码代替 StorageFile.GetFileFromApplicationUriAsync() 方法:

   public Stream GetStreamFromResourceFile(string filename, Type callingType = null)
   {
       var assembly = (callingType ?? GetType()).Assembly;
       string foundResourceName = assembly.GetManifestResourceNames().FirstOrDefault(r => r.EndsWith(filename, StringComparison.InvariantCultureIgnoreCase));
       if (foundResourceName == null)
           throw new FileNotFoundException("File was not found in application resources. Ensure that the filename is correct and its build action is set to 'Embedded Resource'.", filename);
       return assembly.GetManifestResourceStream(foundResourceName);
   }
   

2. 复制一个文件

   await pdfFile.CopyAsync(..);
   

   我们改为:

   await pdfFile.CopyToAsync(newFile);
   

3. 并获取流以供阅读

   (await pdfFile.OpenReadAsync()).AsStreamForRead();
   

   我们使用:

   File.OpenRead(pdfFile);
   

所以最后我们有:

        string filename = "File.pdf";
        var pdfFile = GetStreamFromResourceFile(filename, GetType());
        string newFilePath = Path.Combine(ApplicationData.Current.LocalFolder.Path, filename);
        using (var newFile = File.Create(newFilePath))
        {
            await pdfFile.CopyToAsync(newFile);
        }

        var fileStream = File.OpenRead(newFilePath);