only scan files when it's necessary

[soundsnow]

open mame4droid
scan games (waiting)
open game (loading)
exit game
scan games (waiting)
open game (loading)
exit game
scan games (waiting)

scan games (waiting)

[soundsnow]

I don't add new games, but it automatically scans all files every time

[soundsnow]

I think there are only three situations where it is worthwhile to scan files

1. Close and reopen the app
2. delete games, saves and states in the built-in file manager (like mameui Delete Game Physical Files)
3. scan games manually (like mameui Reload ROMS)
   @seleuco