Instead of using @color/background directly, use ?attr/colorSurface
so that changes can be made to the theming easier. This also
resolves some more minor issues regarding certain widget's
backgrounds.
Change most of the external layout/drawable code to use
colorControlHighlight instead of selection_color so that control
over which kind of selection color is used is more fine-grained.
Refactor/Rewrite the database system to be based on SQLiteOpenHelper instead of Room, as Room will keep empty columns around even after trying to explicitly delete them.
