UI polishing for PocketMaps: instant search for map file names needed!

There has been quite some progress on developing the OSM based app PocketMaps.

This app has offline features in map display via mapsforge and offline routing via graphhopper.

One thing that disturbs me when downloading map files from within the app is, that there is no filter or instant search when typing the first letters of a map file name. (there is even no feature so far to search for a specific map file name.)

Example:
If you want to download the map file for Uruguay, you have to scroll down the whole list manually to the end.

Question:
Does anyone know a simple source code or library that could be used in PocketMap sourcecode to implement a search-as-you-type filter for those map file names?

(With a general internet search about this topic I had no success.)

See also https://github.com/junjunguo/PocketMaps/issues/56