Download as PDF, PPTX
Uploaded byBrian Hsu
Programming Android Application in Scala.
The document discusses using Scala to develop Android applications. Scala allows satisfying three desires at once: REPL, scripting, and compiling. It supports traits for mixin composition, functional programming, static typing with duck typing. SBT is introduced as a build tool for Scala/Android projects that does not require configuration and supports continuous compilation with an Android plugin. Live demos show installing SBT/SBT-Android and creating a sample Scala/Android project. Some limitations of Scala with Android like accessing static protected Java fields are also mentioned.
More Related Content
Similar to Programming Android Application in Scala.
Programming Android Application in Scala.
- 1. Programming Android Applicationin Scala BrianHsu / OSDC.2010
- 2.
- 3.
- 4.
- 5.
- 6.
- 7. 僕我 了最 寫 ！喜 Android 歡 女 全我 都要 是讓 是萌 女手 僕上 燃程 ！機 的式
- 8.
- 9.
- 10.
- 11.
- 12. 寫作 Dynamic Scripting Language
- 13.
- 14.
- 15.
- 16.
- 17.
- 18. def boom puts "Hello World" end puts " 一個小小的 typo" booom 執行期爆炸
- 19.
- 20.
- 22.
- 23.
- 24. A Postfunctional Programming Language onJava Virtual Machine
- 25. Compile to JVM .classByte Code
- 26. 理論上 Full Java Interoperability
- 27.
- 28.
- 29.
- 30.
- 31.
- 32.
- 33.
- 35.
- 36.
- 37.
- 38.
- 39.
- 40.
- 41. Procedure Object Oriented Functional
- 42.
- 43.
- 44.
- 45.
- 46.
- 47.
- 48.
- 49.
- 50.
- 51. 真、 Duck Typing(Ruby)
- 52. 偽‧ Duck Typing(Scala)
- 53.
- 54.
- 55. 僕我 用 了最 Scala ！喜 歡 女 寫 全我 都要 是萌 是讓 女手 燃程 僕上 ！機 的式
- 56.
- 57. Scala compared toJava Scala adds Scala removes + a pure object system - static members + operator overloading - primitive types + closures - break, continue + mixin composition with traits - special treatment of interfaces + existential types - wildcards + abstract types - raw types + pattern matching - enums Modeled in libraries: assert, enums, properties, events, actors, using, queries, …
- 58. Scala cheat sheet(1): Definitions Scala method definitions: Java method definition: def fun(x: Int): Int = { int fun(int x) { result return result } } def fun = result (no parameterless methods) Scala variable definitions: Java variable definitions: var x: Int = expression int x = expression val x: String = expression final String x = expression
- 59. Scala cheat sheet(2): Expressions Scala method calls: Java method call: obj.meth(arg) obj.meth(arg) obj meth arg (no operator overloading) Scala choice expressions: Java choice expressions, stmts: if (cond) expr1 else expr2 cond ? expr1 : expr2 if (cond) return expr1; else return expr2; expr match { case pat1 => expr1 switch (expr) { .... case pat1 : return expr1; case patn => exprn ... } case patn : return exprn ; } // statement only
- 60. Scala cheat sheet(3): Objects and Classes Scala Class and Object Java Class with statics class Sample { class Sample(x: Int, val p: Int) { private final int x; def instMeth(y: Int) = x + y public final int p; } Sample(int x, int p) { this.x = x; object Sample { this.p = p; def staticMeth(x: Int, y: Int) = } x*y int instMeth(int y) { } return x + y; } static int staticMeth(int x, int y) { return x * y; } }
- 61. Scala cheat sheet(4): Traits Java Interface Scala Trait trait T { interface T { int abstractMth(String x) def abstractMth(x: String): Int } def concreteMth(x: String) = x + field (no concrete methods) var field = “!” (no fields) } Java extension + implementation: Scala mixin composition: class C extends Super implements T class C extends Super with T
- 62.
- 63. Android Application 開發流程
- 64.
- 65. $ android createproject -p … $ vim ..... $ ant install
- 66.
- 67.
- 68.
- 69.
- 70.
- 71.
- 72. 以 Scala 為 HostLanguage
- 73.
- 74.
- 75.
- 76.
- 77.
- 78.
- 79.
- 80.
- 81.
- 82.
- 83. Install SBT/SBT-Android ● Install SBT ● http://code.google.com/p/simple-build-tool/ ● Download SBT-Android ● $ git clone http://github.com/brianhsu/sbt-android.git ● Install SBT-Android ● $ cd sbt-android ● $ sbt publish-local
- 84. Create Android/Scala Project ● Create SBT project ● $ mkdir AndroidTest ● $ cd AndroidTest ● $ sbt ● Edit project/build/MyProject.scala ● Edit project/plugins/Plugins.scala ● $ sbt update
- 85.
- 86. Build Scala/Android Project ● $ sbt action ● $ sbt install ● $ sbt android-compile ● $ sbt proguard ● $ sbt zipalign ● $ ...
- 87.
- 88.
- 89.
- 90.
- 91.
- 92.
- 93. Scala 的限制與臭蟲 ● 限制 ● Cannot acess static protected Java field. – 對不起， Google Maps API 用到了。 ● 臭蟲 ● Static Java Inner class 造成 classfile borken / Missing dependency missing dependcy – Google Maps API 踩到地雷了 ● Cyclic dependcy – Google Data API 中計了 – 以於 Scala 2.8 main trunk 中修正 ● 解決方式 ● 用 Java 寫個 Wrapper 唄
- 94.