Xamarin Android R打开文件错误“ IsFileInPublicLocation”

如何解决Xamarin Android R打开文件错误“ IsFileInPublicLocation”

在Android 11中，尝试下载文件并使用默认应用程序将其打开。

该代码在Android版本9和10中有效，并且正确询问用户要使用哪个应用打开文件。

我正在使用xamarin Essentials打开文件

userword == word

同时尝试使用此代码通过电子邮件发送文件时，也会收到完全相同的错误

word = 'python'
rightguesses = []
wrongguesses = []
guesscount = 0

while guesscount < 10:
    print("Here is the current board:")
    for char in word:
        if char in rightguesses:
            print(char,end='')
        else:
            print("_",end='')
    print("\n")
    print("guess a letter")
    guess = input()
    if guess in word:
        rightguesses.append(guess)
        guesscount += 1
        print(guesscount)
    elif guess not in word and guess not in wrongguesses:
        wrongguesses.append(guess)
        print("Incorrect guess")
        guesscount += 1
    elif guess in wrongguesses or guess in rightguesses:
        print("You've already guessed that")
        continue

错误

var filePath = Path.Combine(FileSystem.AppDataDirectory,$"{result.Replace(" ","")}.pdf");
using (FileStream linkFile = new FileStream(filePath,FileMode.Create,FileAccess.ReadWrite))
{
    await pdfDoc.CopyToAsync(linkFile);
}
if (File.Exists(filePath))
{
    await Launcher.OpenAsync(new OpenFileRequest
    {
        File = new ReadOnlyFile(filePath)
    });
}

我尝试使用到公共目录的硬编码路径以及文件路径的其他帮助程序，所有这些都具有相同的错误

var file = new ReadOnlyFile(filePath);
var emailAttach = new EmailAttachment(file);
email.Attachments.Add(emailAttach);
await Email.ComposeAsync(email);

*编辑

修改后的代码

Object reference not set to an instance of an object.


  at Xamarin.Essentials.FileProvider.IsFileInPublicLocation (System.String filename) [0x0000d] in d:\a\1\s\Xamarin.Essentials\Types\FileProvider.android.cs:92 
  at Xamarin.Essentials.Platform.GetShareableFileUri (System.String filename) [0x00000] in d:\a\1\s\Xamarin.Essentials\Platform\Platform.android.cs:105 
  at Xamarin.Essentials.Launcher.PlatformOpenAsync (Xamarin.Essentials.OpenFileRequest request) [0x00000] in d:\a\1\s\Xamarin.Essentials\Launcher\Launcher.android.cs:41 
  at Xamarin.Essentials.Launcher.OpenAsync (Xamarin.Essentials.OpenFileRequest request) [0x00000] in d:\a\1\s\Xamarin.Essentials\Launcher\Launcher.shared.cs:43 
  at AppName.Views.JobDetails.GeneratePDF () [0x0034d] in C:\Users\User\source\repos\AppName\AppName\AppName\Views\JobDetails.xaml.cs:416 

发生错误

string fileDir = @"/storage/emulated/0/Android/data/com.*CompanyName*.*AppName*/files/";

string fileDir = Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData);
(And various other special folders)

string fileDir = FileSystem.CacheDirectory

和

var readOnlyFile = new ReadOnlyFile(filePath);
var openFileReq = new OpenFileRequest();
openFileReq.File = readOnlyFile;
await Launcher.OpenAsync(openFileReq);