Cache book data

[HuiiBuh]

First of all. I really like your audiobook player and it recently replaced the smart audiobook player with PlayBooks.

Problem:

If you open the player and the player is not cached in RAM you see that he loads the books in the not started category. It looks like the player parses the directory for new books after every startup and does not cache the books he already found.

Solution:

Cache every book you find and display them at startup time. Then run your ebook search and add then new books/remove books which are not longer on the device.

And just a tiny nitpick. I think the material spec uses dark shadows for elevation (In your case the currently playing book overlay)
https://material.io/design/color/dark-theme.html#behavior, but if you prefer it your way go ahead and keep it

[Goodwy]

Thanks for the advice. I was just looking for a solution with dark shadows.

[Goodwy]

Fixed in version 2.0