相关疑难解决方法(0)

在我使用 Xamarin Forms 的 Android 10.0 (Q) 应用程序中，我已在清单中正确设置

<?xml version="1.0" encoding="utf-8"?>
<manifest **** />
    <application *** ></application>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
</manifest>

我已通过代码授予权限

var permission = ActivityCompat.CheckSelfPermission(MainActivity.Instance, Manifest.Permission.WriteExternalStorage);

if (permission != Permission.Granted)
{
    ActivityCompat.RequestPermissions(
      MainActivity.Instance, 
      new[] 
      { 
         Manifest.Permission.WriteExternalStorage, 
         Manifest.Permission.ReadExternalStorage 
      }, 1);
}

然而，当我尝试在我的文档或图片文件夹中创建一个文件时，我收到一个权限被拒绝错误：Java.IO.FileNotFoundException: '/storage/emulated/0/Documents/file.txt: open failed: EACCES (Permission denied)' 我错过了什么？

var folder= Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDocuments);
folder.Mkdirs();

var filePath = Path.Combine(folder.AbsolutePath, filename);

// I get a permissions error here 
using (var stream = new Java.IO.FileOutputStream(filePath))
{
     await …

我尝试了“text/csv”甚至“application/vnd.ms-excel”，但 Excel 不会显示在选择列表中。很多其他应用程序也可以。

void shareCsv(Uri uri, Context context) {
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_SEND);
    intent.setType("text/csv");
    intent.putExtra(Intent.EXTRA_STREAM, uri);
    intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

    context.startActivity(intent);
}

同样，在 Mac 上更新到 VS 8.9.1 后，我在尝试编译我的 Android 项目时遇到此错误：

    /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Tooling.targets(5,5): Error XARSD7023: System.IO.DirectoryNotFoundException: Could not find a part of the path '/Users/giulioserra/Library/Android/sdk'.
  at System.IO.Enumeration.FileSystemEnumerator`1[TResult].CreateDirectoryHandle (System.String path, System.Boolean ignoreNotFound) [0x00032] in <36514b14425c4337b446653c547aa9c3>:0 
  at System.IO.Enumeration.FileSystemEnumerator`1[TResult]..ctor (System.String directory, System.IO.EnumerationOptions options) [0x00048] in <36514b14425c4337b446653c547aa9c3>:0 
  at System.IO.Enumeration.FileSystemEnumerable`1+DelegateEnumerator[TResult]..ctor (System.IO.Enumeration.FileSystemEnumerable`1[TResult] enumerable) [0x00000] in <36514b14425c4337b446653c547aa9c3>:0 
  at System.IO.Enumeration.FileSystemEnumerable`1[TResult]..ctor (System.String directory, System.IO.Enumeration.FileSystemEnumerable`1+FindTransform[TResult] transform, System.IO.EnumerationOptions options) [0x00042] in <36514b14425c4337b446653c547aa9c3>:0 
  at System.IO.Enumeration.FileSystemEnumerableFactory.UserDirectories (System.String directory, System.String expression, System.IO.EnumerationOptions options) [0x00014] in /Users/builder/jenkins/workspace/build-package-osx-mono/2020-02/external/bockbuild/builds/mono-x64/external/corefx/src/System.IO.FileSystem/src/System/IO/Enumeration/FileSystemEnumerableFactory.cs:104 
  at System.IO.Directory.InternalEnumeratePaths (System.String path, System.String searchPattern, System.IO.SearchTarget searchTarget, System.IO.EnumerationOptions options) [0x00045] in …