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![≠ Boilerplate
• Perens are (sometimes) optional
• Semicolons are (mostly) optional
• Types are inferred, thus:
ArrayList<GameTileMotionDescriptor> descriptors = new
ArrayList<GameTileMotionDescriptor>();
VS.
val descriptors = new ArrayBuffer[GameTileMotionDescriptor]
PRESENTATION tackmobile.com](https://image.slidesharecdn.com/scalaforandroid-120516125800-phpapp01/85/Scala-for-android-14-320.jpg)
 {
def unless(b: Boolean): Unit = {
if (!b) block
}
}
implicit def
toUnlessClass[T](block: => T): UnlessClass[T] = {
new UnlessClass[T](block)
}
...
foo unless flag
http://naturalsoftware.blogspot.com/2009/05/ruby-unless-scala.html
PRESENTATION tackmobile.com](https://image.slidesharecdn.com/scalaforandroid-120516125800-phpapp01/85/Scala-for-android-37-320.jpg)
Uploaded byTack Mobile
Scala for android
The document is a presentation about using Scala to build Android apps. It introduces Scala and discusses some of its features like being more functional than Java, using traits instead of inheritance, and its suitability for concurrent programming. It provides an example of converting a sample Java project to Scala. Resources for learning more about Scala and using it with Android are also listed.
More Related Content
Scala for android
- 1. Do More withLess: Building Android Apps with Scala Tony Hillerson • Tack Mobile AnDevCon III @thillerson @tackmobile PRESENTATION ANDEVCON • MAY 14, 2012
- 2. ABOUT ME Tony Hillerson SoftwareArchitect & Partner Mobile design and development company based in Denver, CO. • O’Reilly Screencasts • Computer Nerd @tackmobile • Co-creator of FieldTest tackmobile.com @thillerson tony@tackmobile.com PRESENTATION tackmobile.com
- 3. Why Would IConsider Scala? • Write less boilerplate code • More powerful features than Java • Move towards Functional paradigms PRESENTATION tackmobile.com
- 4. N.B. I AmNot a Scala Expert • You can probably stump me • This talk is about how you can explore what Scala might do for you PRESENTATION tackmobile.com
- 5. My Goals • Introduce you to Scala • Introduce you to Scala with Android • Give you a few good reasons to use Scala • Encourage you to become a Polyglot PRESENTATION tackmobile.com
- 6. Be a Polyglot PRESENTATION tackmobile.com
- 7. “ Learn one new language per year - The Pragmatic Programmers PRESENTATION tackmobile.com
- 8. Seven Languages in Seven Weeks http://pragprog.com/book/ btlang/seven-languages-in- seven-weeks PRESENTATION tackmobile.com
- 9. What is Scala? PRESENTATION ANDEVCON • MAY 14, 2012
- 10. What is Scala? • JVM Language • Take advantage of any Java library • Bridges the divide between OO and Functional spaces PRESENTATION tackmobile.com
- 11. scala-lang.org PRESENTATION tackmobile.com
- 12. REPL • Read Execute Print Loop • Command line: scala • Test code quickly PRESENTATION tackmobile.com
- 13. Strongly, Statically Typed • Compile time type checking • Restrictions on how types can be used together • For comparison: • Javascript - Weakly typed, Dynamic • Ruby - Strongly typed, Dynamic PRESENTATION tackmobile.com
- 14. ≠ Boilerplate • Perens are (sometimes) optional • Semicolons are (mostly) optional • Types are inferred, thus: ArrayList<GameTileMotionDescriptor> descriptors = new ArrayList<GameTileMotionDescriptor>(); VS. val descriptors = new ArrayBuffer[GameTileMotionDescriptor] PRESENTATION tackmobile.com
- 15. More OO thanJava • Everything is an object • Operators are actually methods • For instance, override the “+” method PRESENTATION tackmobile.com
- 16. Functional Language • Functions are first class citizens • High order functions: Functions that operate on functions • Avoids mutable state • Could get pretty academic • Scala bridges the gap between OO and Functional PRESENTATION tackmobile.com
- 17. A Javascript Function vardoSomething = function(data) { doSomethingElseWithData(data); } PRESENTATION tackmobile.com
- 18. A Scala Function defdoSomething(data:A):B = { doSomethingElseWithData(data) } PRESENTATION tackmobile.com
- 19. Concurrent • Optional immutable state • Actors - Higher concept than Threads/ Thread Pools PRESENTATION tackmobile.com
- 20. Example Conversion Project PRESENTATION ANDEVCON • MAY 14, 2012
- 21. Slider Puzzle PRESENTATION tackmobile.com
- 22. Experiment: Convert fromJava to Scala • Android • https://github.com/thillerson/Android-Slider-Puzzle • Scala • https://github.com/thillerson/scala-android-slider-puzzle • Mixed results. • I have a lot to learn about Scala PRESENTATION tackmobile.com
- 23. Mike Burns • Thoughtbot • Android and Scala at Android Open • http://robots.thoughtbot.com/post/ 5836463058/scala-a-better-java-for-android • Ohlaunch - https://github.com/mike-burns/ ohlaunch PRESENTATION tackmobile.com
- 24. Scala with Android PRESENTATION ANDEVCON • MAY 14, 2012
- 25. SBT • Build tool (use for Java too) • https://github.com/harrah/xsbt/wiki/ Getting-Started-Welcome PRESENTATION tackmobile.com
- 26. android-plugin • https://github.com/jberkel/android-plugin/ wiki/getting-started • ADB/DDMS Integration • Build and Release PRESENTATION tackmobile.com
- 27. But I NeedMy Eclipse! • http://www.assembla.com/wiki/show/scala- ide/Developing_for_Android PRESENTATION tackmobile.com
- 28. Scala’s Features and Idioms PRESENTATION ANDEVCON • MAY 14, 2012
- 29. vals and vars • var - A variable definition. Required to be initialized when in a function • val - A value definition. Once set, cannot be changed • Basically a “final” • Important consideration for concurrent programming PRESENTATION tackmobile.com
- 30. Methods • Declaration conventions • Suffix notation • Infix notation PRESENTATION tackmobile.com
- 31. Looping • for ( item <- items ) • ranges PRESENTATION tackmobile.com
- 32. Scala Collections • Scala really shines on collections • A good introduction to functional power PRESENTATION tackmobile.com
- 33. Anonymous Function Syntax • ( args ) => ReturnType • ( x:Int ) => x * x PRESENTATION tackmobile.com
- 34. Inheritance in Java • Single Inheritance • Restricting! PRESENTATION tackmobile.com
- 35. Inheritance in C++ • Multiple Inheritance • Mind Blown PRESENTATION tackmobile.com
- 36. Traits • Mixin pattern • Abstract/Interface + implementation PRESENTATION tackmobile.com
- 37. Extending the Language class UnlessClass[T](block: => T) { def unless(b: Boolean): Unit = { if (!b) block } } implicit def toUnlessClass[T](block: => T): UnlessClass[T] = { new UnlessClass[T](block) } ... foo unless flag http://naturalsoftware.blogspot.com/2009/05/ruby-unless-scala.html PRESENTATION tackmobile.com
- 38. Resources PRESENTATION ANDEVCON • MAY 14, 2012
- 39. Books on Scala • http://www.scala-lang.org/node/959 PRESENTATION tackmobile.com
- 40. Positronic • Framework for Android in Scala • Makes use of Actors • http://rst.github.com/tutorial.html PRESENTATION tackmobile.com
- 41. Assembla • http://www.assembla.com/wiki/show/scala- ide/Developing_for_Android PRESENTATION tackmobile.com
- 42. Seven Languages in Seven Weeks http://pragprog.com/book/ btlang/seven-languages-in- seven-weeks PRESENTATION tackmobile.com
- 43. Recap • Scala is perfect for Android • Consider expanding your mind • Be a Polyglot PRESENTATION tackmobile.com
- 44. Thank You @thillerson @tackmobile PRESENTATION ANDEVCON • MAY 14, 2012