Downloaded files get deleted automatically

Question

In my app, there are a few files that users can download. The files get downloaded via the android download manager. But, since a few weeks now, hundreds of users have been complaining that their files automatically keep deleting every 8-12 days, without them even uninstalling the app. (There might be many more users who haven't bothered to complain about the same.)

Now, there could be a number of user-specific reasons why that would happen on a few devices. But considering the huge number of users, it seems that I might have been doing something wrong.

Why would the system/download manager delete the files automatically? Is there a way to inform the system or the download manager to not delete certain files? Or should I just settle with renaming the files after downloading, so as to unlink them from the download manager, and hope that the problem gets solved with just that?

Edit:

Here's the code that I use to download the files:

DownloadManager.Request request = new DownloadManager.Request(Uri.parse(trackLink));
request.setTitle(trackTitle);
request.setDestinationInExternalPublicDir("Tracks", trackTitle + ".mp3");
request.setVisibleInDownloadsUi(false);
DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
manager.enqueue(request);

Answer 1

There is a bigger problem starting in Android Q where value set by setVisibleInDownloadsUi is ignored and it is false by default. The files will be deleted after a week. You can test it by: download file, change date in calendar by 2 months for example, call this in terminal:

adb shell cmd jobscheduler run -f com.android.providers.downloads -100

It starts job from DownloadIdleService where old and forbidden files are deleted. You can see in logcat (set no filter) that DownloadManager try to delete your files.

To prevent from that you can:

• download files to Environment#getExternalStoragePublicDirectory(String) with Environment#DIRECTORY_DOWNLOADS) - this is the only path starting in Android Q where downloads are visible and should not be deleted
• change file name after downloading (in DownloadedReceiver for example)

Answer 2

I also came across this issue. Looking at the source for DownloadIdleService it appears that if the download are set to not be visible in the UI they're deleted after 7 days as they're considered "stale". Here's the javadoc fromDownloadIdleService:

/**
 * Remove stale downloads that third-party apps probably forgot about. We
 * only consider non-visible downloads that haven't been touched in over a
 * week.
 */

https://android.googlesource.com/platform/packages/providers/DownloadProvider/+/master/src/com/android/providers/downloads/DownloadIdleService.java#110