My presentation for Droidcon London, 2009

1. Android and Scala: is Android ready for a scala invasion? Presented by Akshay Dashrath

2. Which approach?

3. Performance Google Best Practices (http://developer.android.com/guide/practices/design/performance.html) NDK

4. For example…………

5. What's wrong with Java?

6. What about exploring alternative languages?

7. What about exploring alternative languages?

8. Abstraction Performance

9. Scala allows the programmer…… to write Clearer and more concise code

11. Statically typed

12. Supports type inference

13. val file = new File("/sdcard/list.txt")

17. Flexibility of Scala makes……… Its quite possible to develop internal DSL (Domain Specific Languages) Example val name = “scala” name contains “a” rather than name.contains(“a”) Wrappers class ShouldWrapper(s: String) { def should = "should was invoked on " + s } implicit def convert(s: String) = new ShouldWrapper(s) “scala”.should Output = java.lang.String = should was invoked on scala

18. Scala also……… Allows use of Scala as well as Java and Android APIs seamlessly

19. A.scala B.scala A.class B.class AB.dex AB.apk scalac dex zip

20. Scala is also designed with……… Message passing in mind Between threads So is Android Between processes/applications

25. And finally the shortcomings…… Performance on the Dalvik Virtual Machine Quick Sort of 100 integers and search for a string in Scala = 15.2 sec (java = 5.9 sec) Quick Sort method in Scala = 5.32 sec (Java = 1.051 sec) Memory Lack of support Learning curve

26. But Why?......... Boxing/Unboxing Anonymous classes created for closures Recursion? Solution Scala 2.8 DalvikJIT ProGuard

27. Contact akshaydashrath@gmail.com www.akshaydashrath.com

28. Questions