Allow app data to be included in encrypted android backup

[MrElliwood]

Expected Behavior

When backing up apps using the backup feature provided by the OS, app data should be included if the backup is encrypted.

Current Behavior

When backing up apps using the backup feature provided by the OS, app data does not get backed up.

Possible Solution

The backup provider SeedVault describes this issue in their FAQ, and links to a possible solution. Changing this behaviour should be a small change in https://github.com/arduia/ProExpense/blob/3d97c9a9f56be8c8c80f29e0e067df3e9f7086c5/app/src/main/AndroidManifest.xml#L19 and adding /res/xml/backup.xml to define the wanted behaviour. See here for the details

• https://github.com/seedvault-app/seedvault/wiki/FAQ#why-do-some-apps-not-allow-to-get-backed-up
• https://github.com/grote/Transportr/commit/4dc38f429f75909a088d8bd8a5b3b5ddd8030f71

Context

I've got my own server with a nextcloud installation where I save encrypted backups of my apps. The data of the apps that get backed up is secure because everything is encrypted. This means that I should be able to safely include the ProExpense data, and i wouldn't have to worry about doing manual backups of my data (and app settings).

Your Environment

• Google Pixel 5, running on GrapheneOS (Android 11)
• Using the integrated SeedVault 11-1.1 for backups

[arduia]

Thanks @MrElliwood for your contribution. Let me take some time to consider it should be in the app or not.

[MrElliwood]

Another thing that's worth mentioning is the change in behaviour oft the backup feature once Android 12 is released. The android:allowBackup="false" does no longer disable device to device transfers. It only disables cloud backup. For more details see here: https://developer.android.com/about/versions/12/backup-restore