SAF - Invalid Uri error when copying file from private app folder to authorized SAF folder

Question

My Android has to copy a file from private app folder to a SAF location that was previously granted permissions and authorized. The code is:

static boolean copyDocumentFileToTargetFolderWithNewName(Activity activity, String docUri,String targetFolderUri,String newName)
{
    deleteIfExisting(activity,Uri.parse(targetFolderUri),newName);
    ContentResolver resolver = activity.getContentResolver();
    boolean result=false;
    Log.d("copy",docUri+" "+targetFolderUri+" "+newName);
    Log.d("doc exists",String.valueOf(fileExists(activity,docUri)));  //error here
    try {
        DocumentsContract.copyDocument(resolver,Uri.parse(docUri),Uri.parse(targetFolderUri));//or error here
        DocumentsContract.renameDocument(resolver,Uri.parse(docUri),newName);
        result=true;
    } catch (FileNotFoundException e) {
        result=false;
    }

    return result;
}

and

static public boolean fileExists(Activity activity,String fileUriString)
{
    ContentResolver contentResolver;
    contentResolver = activity.getContentResolver();
    String parentFolderUriString=StringUtils.fromLastSlashLeft(fileUriString);
    String fileName=StringUtils.fromLastSlashRight(fileUriString);
    Uri parentFolderUri=Uri.parse(parentFolderUriString);
    boolean exists;
    DocumentFile docFile=DocumentFile.fromTreeUri(activity,parentFolderUri).findFile(fileName); //error here
    exists= (null!=docFile);
    return exists;
}

(with some self-explanatory string utility calls)

Here the result from the Log.d() line

D/copy: file:///storage/emulated/0/Android/data/com.myappname.app/folder/subfolder/file.txt content://com.android.providers.downloads.documents/tree/raw%3A%2Fstorage%2Femulated%2F0%2FDownload%2FSAFfolder/newname.txt

I get

java.lang.IllegalArgumentException: Invalid URI: file:///storage/emulated/0/Android/data/com.myappname.app/folder/subfolder/file.txt

at

DocumentFile docFile=DocumentFile.fromTreeUri(activity,parentFolderUri).findFile(fileName);

in the second method

or, when Log.d() is commented,

java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Bundle android.content.ContentProviderClient.call(java.lang.String, java.lang.String, android.os.Bundle)' on a null object reference

at this line:

DocumentsContract.copyDocument(resolver,Uri.parse(docUri),Uri.parse(targetFolderUri));

in the first method. What's wrong with my code? Aren't private folder uris authorized? How to authorize them?

Answer 1

What's wrong with my code?

Neither docUri nor parentFolderUri is a document Uri. They are Uri values that you created using Uri.fromFile() or something. You can tell because they have the file scheme.

With regards to your immediate crash, fromTreeUri() requires a document Uri. Use fromFile() for file Uri values.

Once you get past that, I expect that you will crash in your copyDocument() call. That's what I originally thought the problem was, until I re-read your question. You are trying to copy a non-document Uri (docUri), and the JavaDocs for copyDocument() state that the first parameter needs to be a document Uri:

document with Document#FLAG_SUPPORTS_COPY This value must never be null.

When DocumentsContract refers to a Uri as a "document", it means a Uri obtained through DocumentsContract itself. That would include a Uri obtained through ACTION_OPEN_DOCUMENT or a Uri obtained through a tree DocumentFile. However, that will not cover:

• A Uri created by Uri.fromFile()
• A Uri from FileProvider.getUriForFile()
• A Uri created by Uri.parse() from an http or https URL
• Etc.

Aren't private folder uris authorized?

It is not a question of "authorization". fromTreeUri() expects a document Uri. copyDocument() expects a document Uri. You cannot use them with non-document Uri values, that's all.