filesystems - Folder added on Android is not visible via USB

Question

I'm trying to save pictures in a subfolder on Android. Here's a bit of my code:

File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
path = new File(path, "SubDirName");
path.mkdirs();

(I've tried getExternalStorageDirectory instead of getExternalStoragePublicDirectory and the Pictures folder instead of DCIM.)

Any subfolder I add, including its contents, don't show up in Windows Explorer when the device is connected via USB. It does show in the Android File Manager, though.

I've tried broadcasting the ACTION_MEDIA_MOUNTED intent on the new directory's parent. It didn't work.

If I add a file in Windows, it shows up on Android. If I add a file on Android via the File Manager, it shows up in Windows. If I add the file programmatically, it shows up on the Android File Manager, but not in Windows Explorer. And I need to get it from Windows, and I don't want the final user to have to create the folder manually.

What am I doing wrong?

Answer 1

I faced the same issue and rebooting either the Android device or the PC is not a practical solution for users. :)

This issue is through the use of the MTP protocol (I hate this protocol). You have to initiate a rescan of the available files, and you can do this using the MediaScannerConnection class:

// Snippet taken from question
File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
path = new File(path, "SubDirName");
path.mkdirs();

// Initiate a media scan and put the new things into the path array to
// make the scanner aware of the location and the files you want to see
MediaScannerConnection.scanFile(this, new String[] {path.toString()}, null, null);