Google drive rest API, Download files from root folder only

Question

I am trying to download files in the root directory only. Currently I am not specifying any folders as I do not know how to so it downloads the most recent files that are in other folders that aren't the root. All I would like are the files in the root. The code that is getting the files and the download URLs is below:

public static void startDownload() throws IOException, ParseException {

    Drive serv = getDriveService();

    FileList result = serv.files().list().setMaxResults(10).execute(); //there are 10 files in the root folder     

    List<File> listA = result.getItems();

    if (listA == null || listA.isEmpty()) {
        System.out.println("No files found.");
    } else {
        System.out.println("Files:"+lista.size());
        for (File file : listA) {
            System.out.printf("%s (%s)\n", file.getTitle(), file.getDownloadUrl());
            downloadFile(serv, file);
        }
    }
}

I would like to download all files in the root file only and not in any other folders. Any help would be appreciated.

Answer 1

There are a number of considerations.

Your line 3 needs to be

String q = "trashed = false and 'root' in parents and mimeType != 'application/vnd.google-apps.folder' "

FileList result = serv.files().list().setFields("*").setQ(q).setMaxResults(10).execute();

You need to be aware that this will return a maximum of 10 results, but even more so, you need to be aware that there is no minimum number of results. This means that if you have 11 files, you might get 10 in the first iteration and 1 in the 2nd. However, you could also get 1 and 10, or 3 and 6 and 2, or 0 and 0 and 1 and 10. You need to keep fetching results until the value of getNextPageToken() == null. So your line

if (listA == null || listA.isEmpty()) {

should be something like

if (result.getNextPageToken() == null) {

I realise that you've copy/pasted from the official documentation, but sadly that documentation is wrong.

Answer 2

You need to use the Q parameter to search

q string A query for filtering the file results. See the "Search for Files" guide for supported syntax.

Sending something like the following will return everything that is not a folder with the parent of root.

mimeType != 'application/vnd.google-apps.folder' and 'root' in parents