Embedding programming has never been easier after the introduction of modern mobile APIs like Android SDK and iOS SDK. Nevertheless for realtime applications new areas for potential bottlenecks may arise as those extra layers add more complexity to your application.
A clear example may happen with the Dalvik GC (Garbage Collector), which coupled with a realtime 2D/3D Engine generating many objects for each frame, will (for sure) showcase frame drops when the GC hits in. This is hard to solve as Java makes really easy to create new objects that encapsulate your required functionality but hides from you how and when the memory will be collected. Hey! it creates objects everywhere, for iterators, enums, sorting alogrithms…I personally think Dalvik needs some improvement in memory management areas but meanwhile we just need to avoid those problems and minimize them as possible.
Dont create objects! No, seriously, don’t create new objects in your game loop. Use object pools as much as possible. This is an area ShadingZen engine is improving and is one of the reasons you should always create new actors using the “spawn” method.
Don’t call your own methods, use the objects properties within the objects code and use methods to access functionality from outside. Also avoid using getters and setters, but pack functionality in just one method call instead of using the getted property from outside. For example if you want to make an actor explode you may need to compute explosion velocity and actor final destination from outside. Instead create a “makeExplode” method for that and compute everything within the object code. Dalvik makes calling methods slow.
If you are using OpenGL ES avoid changing states, pack drawing calls sharing the same state and run them at once.
DDMS is your friend. I know how much you hate its awkward interface but you need it, profile often!
Check this paper as it contains basic guidelines to avoid performance bottlenecks in your realtime applications: http://dl.google.com/io/2009/pres/WritingRealTimeGamesforAndroid.pdf
Performance is an area the next version 1.0-beta2 of ShadingZen is receiving much love.