如何从 Uri xamarin android 获取实际路径

我想从 Uri 获取实际路径，当我使用意图选择文件时，它将返回 URI，但下面的代码行无法将 URI 转换为字符串路径

打开文件选择器

public static void PickFile(Activity context)
{
    Intent intent = new Intent(Intent.ActionGetContent);
    intent.SetType("*/*");
    context.StartActivityForResult(intent, PICKFILE_RESULT_CODE);
}

获取结果

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
    if(requestCode == PICKFILE_RESULT_CODE)
    {
        string filepath = GetRealPathFromURI(MainActivity.act, data.Data);
    } 
}

public static string GetRealPathFromURI(Activity act, Android.Net.Uri contentURI)
{
    try
    {
        ICursor cursor = act.ContentResolver.Query(contentURI, null, null, null, null);
        cursor.MoveToFirst();
        string documentId = cursor.GetString(0);
        documentId = documentId.Split(':')[1];
        cursor.Close();

        cursor = act.ContentResolver.Query(
        MediaStore.Images.Media.ExternalContentUri,
        null, MediaStore.Images.Media.InterfaceConsts.Id + " = ? ", new[] { documentId }, null);
        cursor.MoveToFirst();
        string path = cursor.GetString(cursor.GetColumnIndex(MediaStore.Images.Media.InterfaceConsts.Data));
        cursor.Close();

        return path;
    }
    catch(Exception e)
    {
        Log.Debug("TAG_DATA",e.ToString());
        return "";
    }
}

Error

System.IndexOutOfRangeException：索引超出范围 大批。

谁能向我解释一下，我在这段代码中做的事情有什么问题。

如何从 Uri xamarin android 获取实际路径

我注意到你正在使用MediaStore.Images.Media.ExternalContentUriproperty，你想要的是获取Gallery Image的真实路径吗？

如果你想实现这个功能，你可以阅读我的回答：获取图库图像的路径？ https://stackoverflow.com/questions/45692514/get-path-of-gallery-image-xamarin/45725693#45725693

private string GetRealPathFromURI(Android.Net.Uri uri)
{
    string doc_id = "";
    using (var c1 = ContentResolver.Query(uri, null, null, null, null))
    {
        c1.MoveToFirst();
        string document_id = c1.GetString(0);
        doc_id = document_id.Substring(document_id.LastIndexOf(":") + 1);
    }

    string path = null;

    // The projection contains the columns we want to return in our query.
    string selection = Android.Provider.MediaStore.Images.Media.InterfaceConsts.Id + " =? ";
    using (var cursor = ContentResolver.Query(Android.Provider.MediaStore.Images.Media.ExternalContentUri, null, selection, new string[] { doc_id }, null))
    {
        if (cursor == null) return path;
        var columnIndex = cursor.GetColumnIndexOrThrow(Android.Provider.MediaStore.Images.Media.InterfaceConsts.Data);
        cursor.MoveToFirst();
        path = cursor.GetString(columnIndex);
    }
    return path;
}

Update :

这是一个解决方案：

private string GetActualPathFromFile(Android.Net.Uri uri)
{
    bool isKitKat = Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Kitkat;

    if (isKitKat && DocumentsContract.IsDocumentUri(this, uri))
    {
        // ExternalStorageProvider
        if (isExternalStorageDocument(uri))
        {
            string docId = DocumentsContract.GetDocumentId(uri);

            char[] chars = { ':' };
            string[] split = docId.Split(chars);
            string type = split[0];

            if ("primary".Equals(type, StringComparison.OrdinalIgnoreCase))
            {
                return Android.OS.Environment.ExternalStorageDirectory + "/" + split[1];
            }
        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri))
        {
            string id = DocumentsContract.GetDocumentId(uri);

            Android.Net.Uri contentUri = ContentUris.WithAppendedId(
                            Android.Net.Uri.Parse("content://downloads/public_downloads"), long.Parse(id));

            //System.Diagnostics.Debug.WriteLine(contentUri.ToString());

            return getDataColumn(this, contentUri, null, null);
        }
        // MediaProvider
        else if (isMediaDocument(uri))
        {
            String docId = DocumentsContract.GetDocumentId(uri);

            char[] chars = { ':' };
            String[] split = docId.Split(chars);

            String type = split[0];

            Android.Net.Uri contentUri = null;
            if ("image".Equals(type))
            {
                contentUri = MediaStore.Images.Media.ExternalContentUri;
            }
            else if ("video".Equals(type))
            {
                contentUri = MediaStore.Video.Media.ExternalContentUri;
            }
            else if ("audio".Equals(type))
            {
                contentUri = MediaStore.Audio.Media.ExternalContentUri;
            }

            String selection = "_id=?";
            String[] selectionArgs = new String[] 
            {
                split[1]
            };

            return getDataColumn(this, contentUri, selection, selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".Equals(uri.Scheme, StringComparison.OrdinalIgnoreCase))
    {

        // Return the remote address
        if (isGooglePhotosUri(uri))
            return uri.LastPathSegment;

        return getDataColumn(this, uri, null, null);
    }
    // File
    else if ("file".Equals(uri.Scheme, StringComparison.OrdinalIgnoreCase))
    {
        return uri.Path;
    }

    return null;
}

public static String getDataColumn(Context context, Android.Net.Uri uri, String selection, String[] selectionArgs)
{
    ICursor cursor = null;
    String column = "_data";
    String[] projection = 
    {
        column
    };

    try
    {
        cursor = context.ContentResolver.Query(uri, projection, selection, selectionArgs, null);
        if (cursor != null && cursor.MoveToFirst())
        {
            int index = cursor.GetColumnIndexOrThrow(column);
            return cursor.GetString(index);
        }
    }
    finally
    {
        if (cursor != null)
            cursor.Close();
    }
    return null;
}

//Whether the Uri authority is ExternalStorageProvider.
public static bool isExternalStorageDocument(Android.Net.Uri uri)
{
    return "com.android.externalstorage.documents".Equals(uri.Authority);
}

//Whether the Uri authority is DownloadsProvider.
public static bool isDownloadsDocument(Android.Net.Uri uri)
{
    return "com.android.providers.downloads.documents".Equals(uri.Authority);
}

//Whether the Uri authority is MediaProvider.
public static bool isMediaDocument(Android.Net.Uri uri)
{
    return "com.android.providers.media.documents".Equals(uri.Authority);
}

//Whether the Uri authority is Google Photos.
public static bool isGooglePhotosUri(Android.Net.Uri uri)
{
    return "com.google.android.apps.photos.content".Equals(uri.Authority);
}

获取实际路径OnActivityResult :

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
    base.OnActivityResult(requestCode, resultCode, data);
    if (requestCode == 0)
    {
        var uri = data.Data;
        string path = GetActualPathFromFile(uri);
        System.Diagnostics.Debug.WriteLine("Image path == " + path);

    }
}