android storage-access-framework documentfile

What is the "authority" that DocumentsContract.moveDocument() needs?

I have a simple file inside either the apps getExternalFilesDir or a user selected folder. When i create a subfolder and try to move the file from the parent folder into that newly created subfolder moveDocument() fails.

Logcat says

W/DocumentsContract: Failed to move document
java.lang.IllegalArgumentException: Unknown authority 
    at android.content.ContentResolver.call(ContentResolver.java:2412)
    at android.provider.DocumentsContract.moveDocument(DocumentsContract.java:1520)

Both DocumentFiles give an empty string when i try .getUri().getAuthority()

// file and subfolder are under the same parent
DocumentsContract.moveDocument(context.getContentResolver(),
                                    file.getUri(),
                                    subfolder.getParentFile().getUri(),
                                    subfolder.getUri());

Both DocumentFiles exist, i even create files inside that subfolder and that works fine, but i need to move this one from the parent into the sub.

edit:

// if user selected
DocumentFile dir       = DocumentFile.fromTreeUri(context, persistedUri);
// if 'internal'
DocumentFile dir       = DocumentFile.fromFile(getContext().getExternalFilesDir(null));
DocumentFile subfolder = dir.createDirectory(name);
DocumentFile file      = dir.createFile("video/mp4", vidname);

// Uris internal
file:///storage/emulated/0/Android/data/com.foo.bar/files/
file:///storage/emulated/0/Android/data/com.foo.bar/files/vid
file:///storage/emulated/0/Android/data/com.foo.bar/files/1656602728866.mp4

Solution

All Uri values passed to moveDocument() have to be "document" Uri values, either obtained directly from the Storage Access Framework or derived from other Uri values that were (e.g., a particular document in a tree obtained by ACTION_OPEN_DOCUMENT_TREE / ActivityResultContracts.OpenDocumentTree). In particular, moveDocument() only works within a single provider, and only if FLAG_SUPPORTS_MOVE is included.

file: Uri values, whether created directly or via DocumentFile, are ineligible.