And found out that you use Vector instead of ArrayList.

Also, you should avoid redundancy and repetitive calculations.

For example in draw():

               

                if (sound)
               
               

                      image(no_sound, win_x, win_height + win_y - Math.round(50 * ratio), Math.round(50 * ratio), Math.round(50 * ratio));
               
               

                else
               
               

                      image(sound_im, win_x, win_height + win_y - Math.round(50 * ratio), Math.round(50 * ratio), Math.round(50 * ratio));
               

You make your program recalculates  round(50 * ratio) many times.

Why not cache it in a variable and reuse it?

final int rounded = round(ratio*50);

if (sound)  image(no_sound, win_x, win_height + win_y - rounded, rounded, rounded);
else        image(sound_im, win_x, win_height + win_y - rounded, rounded, rounded);

thanks, some good points there! (And also sorry for what a mess the code is, I at least cleaned up the repo since).

I was using Vector in Java, like, ever, never actually bothered with checking the complexity (Just expected it to be sorta derived from C++). Thanks for the info 

Also there were some redundant calculations apart the one you have mentioned (the "ratio" is moreover set based on resolution, so I actually have to compute it once), I've cleared what I found.

But in general the performance improvement is not observable. There are two main puzzles there for me:

I can not use PImage::resize(), cause on Android it throws following (works in Java, though):

and that means that image must be scaled every time it is used ... that's bad, but dunno how to work around it (I need like 50 different sizes for each images, so pre-building them is not really an option). I Goggled the problem and found no other solution.

Other thing that puzzles me is that I have in general roughly 3 MB of resources and nothing is being loaded more than once and neither copied, but the app takes like 30 MB of RAM when running.