Android 11 (R) file path access

Question

According to the docs file path access is granted in Android R:

Starting in Android 11, apps that have the READ_EXTERNAL_STORAGE permission can read a device's media files using direct file paths and native libraries. This new capability allows your app to work more smoothly with third-party media libraries.

The problem is that I can't get the file path from MediaStore, so how are we supposed to read a file path that we can't access/retrieve? Is there a way, I'm not aware of, that we can get the file path from MediaStore?

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Furthermore, the docs say the following:

All Files Access

Some apps have a core use case that requires broad file access, such as file management or backup & restore operations. They can get All Files Access by doing the following:

1. Declare the MANAGE_EXTERNAL_STORAGE permission.
2. Direct users to a system settings page where they can enable the Allow access to manage all files option for your app.

This permission grants the following:

• Read access and write access to all files within shared storage.
• Access to the contents of the MediaStore.Files table.

But I do not need all file access, I only want the user to select a video from MediaStore and pass the file path to FFmpeg(it requires a file path). I know that I can no longer use the _data column to retrieve a file path.

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Please note:

• I know a Uri is returned from MediaStore and does not point to a file.
• I know that I can copy the file to my application directory and pass that to FFmpeg, but I could do that before Android R.
• I can not pass FileDescriptor to FFmpeg and I can not use /proc/self/fd/ (I get /proc/7828/fd/70: Permission denied when selecting a file from the SD Card), have a look at this issue.

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So what am I supposed to do, am I missing something? What was meant with can read a device's media files using direct file paths and native libraries?

Answer 1

After asking a question on issuetracker, I've come to the following conclusions:

• On Android R, the File restrictions that were added in Android Q is removed. So we can once again access File objects.

• If you are targeting Android 10 > and you want to access/use file paths, you will have to add/keep the following in your manifest:

  android:requestLegacyExternalStorage="true"
  

  This is to ensure that file paths are working on Android 10(Q). On Android R this attribute will be ignored.

• Don't use DATA column for inserting or updating into Media Store, use DISPLAY_NAME and RELATIVE_PATH, here is an example:

  ContentValues valuesvideos;
  valuesvideos = new ContentValues();
  valuesvideos.put(MediaStore.Video.Media.RELATIVE_PATH, "Movies/" + "YourFolder");
  valuesvideos.put(MediaStore.Video.Media.TITLE, "SomeName");
  valuesvideos.put(MediaStore.Video.Media.DISPLAY_NAME, "SomeName");
  valuesvideos.put(MediaStore.Video.Media.MIME_TYPE, "video/mp4");
  valuesvideos.put(MediaStore.Video.Media.DATE_ADDED, System.currentTimeMillis() / 1000);
  valuesvideos.put(MediaStore.Video.Media.DATE_TAKEN, System.currentTimeMillis());
  valuesvideos.put(MediaStore.Video.Media.IS_PENDING, 1);
  ContentResolver resolver = getContentResolver();
  Uri collection = MediaStore.Video.Media.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY);
  Uri uriSavedVideo = resolver.insert(collection, valuesvideos);
  

• You can no longer use the ACTION_OPEN_DOCUMENT_TREE or the ACTION_OPEN_DOCUMENT intent action to request that the user select individual files from Android/data/,Android/obb/and all sub-directories.

• It is recommended to only use File objects when you need to perform "seeking", like when using FFmpeg, for example.
• You can only use the data column to access files that are on the disk. You should handle I/O Exceptions accordingly.

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If you want to access a File or want a file path from a Uri that was returned from MediaStore, I've created a library that handles all the exceptions you might get. This includes all files on the disk, internal and removable disk. When selecting a File from Dropbox, for example, the File will be copied to your applications directory where you have full access, the copied file path will then be returned.

Answer 2

For getting path, i'm coping file with fileDescriptor to new path & i use that path.

Finding File Name:

private static String copyFileAndGetPath(Context context, Uri realUri, String id) {
    final String selection = "_id=?";
    final String[] selectionArgs = new String[]{id};
    String path = null;
    Cursor cursor = null;
    try {
        final String[] projection = {"_data", "_display_name"};
        cursor = context.getContentResolver().query(realUri, projection, selection, selectionArgs,
                null);
        cursor.moveToFirst();
        final String fileName = cursor.getString(cursor.getColumnIndexOrThrow("_display_name"));
        File file = new File(context.getCacheDir(), fileName);

        FileUtils.saveAnswerFileFromUri(realUri, file, context);
        path = file.getAbsolutePath();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return path;
}

Copy With File Descriptor:

fun saveAnswerFileFromUri(uri: Uri, destFile: File?, context: Context) {
    try {
        val pfd: ParcelFileDescriptor =
            context.contentResolver.openFileDescriptor(uri, "r")!!
        if (pfd != null) {
            val fd: FileDescriptor = pfd.getFileDescriptor()
            val fileInputStream: InputStream = FileInputStream(fd)
            val fileOutputStream: OutputStream = FileOutputStream(destFile)
            val buffer = ByteArray(1024)
            var length: Int
            while (fileInputStream.read(buffer).also { length = it } > 0) {
                fileOutputStream.write(buffer, 0, length)
            }

            fileOutputStream.flush()
            fileInputStream.close()
            fileOutputStream.close()
            pfd.close()
        }
    } catch (e: IOException) {
        Timber.w(e)
    }

}