Very nice. Worked okay on my phone. A bit of a lagging from time to time. (HTC Desire HD)

I must say though, that the ad-thingy on the top really dragged the feel of quality of the whole app down very much.
Also, it covered some of the text when the app started.

But very nice work!

I really enjoyed playing with this app! As a suggestion for future versions, I think that if the creatures don't destroy outright when they collide and they have some more movements options, such as flocking and periodical cycles, then the variety of the sound patterns would be much larger. 

Just did an update fixing some bugs including one that caused a crash. Also added a slider that lets you scale the force between the particles, and also reverse it (to get repelling particles). I promised to do really regular updates, but I'm pretty stuck coding some other things that I actually get a living from and I'm also starting a new degree in a couple of days so it might get a little hectic, though I'm still planning some stuff for this one, and the next step is to add some real time audio synthesis.

Great stuff. May I ask what libraries you have used? Particularly for the physics and the audio.

I didn't really use any libraries at all, just Processing. I wrote my own physics (really simple vector stuff, each particle has a velocity vector, and a vector pointing towards each nearby object, and you just add the components and scale with the inverse square law). The audio is just using the Android MediaPlayer class.

Interesting. Did you have any problems getting the audio to work? I must say after reading about the latency in Android devices I was pleasantly surprised at how responsive the sound is in your app. Do you begin buffering the audio when the objects collide, or do you have to do some kind of pre-buffering and just trigger the sound when the objects collide?

Also if you have any general tips or thread/website recommendations for developing an Android app with processing then I'd be immensely grateful. I've been wanting to do something along these lines for a while, and your app has gone a longway to convincing me that it might be worthwhile.

Oh, and one last question - the menu buttons. Did you write them from scratch? Or are there some good base classes that can be exploited? They always seem such a small part of an app, but are surprisingly tricky to get right (especially, from what I read, with Android & Processing)

Many thanks in advance. And well done again on this excellent creation.

can i ask, how do you get the app to not reload every time you rotate the screen?

Joesteve51: I disabled screen rotating (in the manifest I think).

petejonze: Hey, sorry I didn't answer your question, I only now just noticed people have commented on this thread.

"Did you have any problems getting the audio to work? I must say after reading about the latency in Android devices I was pleasantly surprised at how responsive the sound is in your app. Do you begin buffering the audio when the objects collide, or do you have to do some kind of pre-buffering and just trigger the sound when the objects collide?"

I do it very simply. I just load all the samples into SoundPool, and simply 'play' them when objects collide. It's probably not the best way to do it, but it works.They're all pre-buffered in that regard. The latency is probably high, but it's not noticeable since you're not actually playing anything directly.

"Also if you have any general tips or thread/website recommendations for developing an Android app with processing then I'd be immensely grateful. I've been wanting to do something along these lines for a while, and your app has gone a longway to convincing me that it might be worthwhile."

Assuming you know how to use processing, it was really simple for me. I know there is now a really good Eclipse plug-in that essentially turns it into a processing editor, so you can just as you would in processing. There is almost nothing different in the way you code your app for Android, it's still just like writing a normal processing sketch (which is probably what makes it cool). I did it by exporting the Java project from Processing and then loading it in Eclipse.

"Oh, and one last question - the menu buttons. Did you write them from scratch? Or are there some good base classes that can be exploited? They always seem such a small part of an app, but are surprisingly tricky to get right (especially, from what I read, with Android & Processing)"

The menu buttons I wrote myself, although the sliders are taken from the processing tutorial and adapted to multitouch using my own multitouch handler, which you can find here:

http://forum.processing.org/topic/multitouch-solution-long-code

Good luck, Android Processing rules!
Also check out my new app, maybe, this one is an actual low latency real time synthesizer using Processing and PureData:
https://play.google.com/store/apps/details?id=com.bv.synth&hl=en

As I said before, you should put an instruction in your manifest saying that the app should only run in landscape mode.

<activity android:name="xxxxxx.xxx.xx.x.yourApp"
              android:screenOrientation="landscape">

Yeah, I took some phones off the compatibility list because some people reported crashes. It was my first ever app so I'm the only one to blame really.