Enhancement: option to store database on /sdcard

[tom709]

Would it be possible to modify ShoppingList such that the user can choose to store the database on /sdcard instead of in internal memory? Google has deprecated "adb backup", so it will stop working in future versions of Android. When that happens, it will be impossible for a user to create backups of data that an app stores in internal memory. In order not to risk losing data, it will be necessary to store it under /sdcard where it can be accessed by a backup solution.

[clach04]

I think stebeh@440ebc0 by @stebeh may resolve this.

[clach04]

Unclear if #63 is related?