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Which programming languages can I use on Android Dalvik?
Mostly, Android applications are written in Java. But i heard that its also possible to use Scala or some other languages. And I also read that it's possible to include native C/C++ code.
Is there a refernce/list available that shows which languages can be used?
Scala is supported. See example.
Support for other languages is problematic:
7) Something like the dx tool can be forced into the phone, so that Java code could in principle continue to generate bytecodes, yet have them be translated into a VM-runnable form. But, at present, Java code cannot be generated on the fly. This means Dalvik cannot run dynamic languages (JRuby, Jython, Groovy). Yet. (Perhaps the dex format needs a detuned variant which can be easily generated from bytecodes.)
Java and C,
C used for low level funtionalities and deveice connectivities
Java used for Framework and Application Level
you may find more information in andorid developers site.
Clojure can be used, but it's slow.
See also: Clojure fork for Android, and a tutorial.
I made good experiences with Scala.
I use the simple build tool (sbt: http://code.google.com/p/simple-build-tool/) with the Android-Plugin (http://github.com/jberkel/android-plugin)
As stated above, many languages are avalible for developing in Android. Java, C, Scala, C++, several scripting languages etc. Thanks to Mono you are also able to develop using C# and the .Net framework. Here you have some speedcomparisions: http://www.youtube.com/watch?v=It8xPqkKxis