Scala On Android

An overview of the current state of affairs when developing Android apps with Scala, and examine why contrary to popular belief it is ready for prime time. We will discover some of the tools and more useful libraries, and explore how Scala on Android helps circumvent most of the limitations of Java and the Android SDK

Transcript

1. SCALA ON ANDROID The current state of affairs
3. WHO ARE WE? Fede Fernández Scala Software Engineer at 47 Degrees @fede_fdz Javi Pacheco Scala Software Engineer at 47 Degrees @javielinux
4. BUILD TOOLS
5. Android SDK Plugin https://github.com/pfn/android-sdk-plugin addSbtPlugin("com.hanhuy.sbt" % "android-sdk-plugin" % "1.5.9")
6. Android SDK Plugin Active Android build cycle Extra features Supports AAR, JAR and APK artifact types
7. Scala byte code size reduced ~ (2.8M) Size Matters
8. Proguard and Multidex Problem: 65k Methods and Scala library size
9. Proguard and Multidex Problem: 65k Methods and Scala library size Solution 1: Proguard to remove unused methods
10. Proguard and Multidex Problem: 65k Methods and Scala library size Solution 1: Proguard to remove unused methods Solution 2: Multidex to deal with method limit
11. Typed Resources class MainActivity extends AppCompatActivity with TypedFindView { lazy val text: TextView = findView(TR.textView) override def onCreate(bundle: Bundle) = { super.onCreate(bundle) setContentView(R.layout.my_activity) text.setText("Hi!") } }
12. SBT Console > compile …. …. [success] Total time: 6 s, completed 20-nov-2015 9:52:48
13. SBT Console > test …. …. [info] 69 examples, 0 failure, 0 error [info] Passed: Total 159, Failed 0, Errors 0, Passed 159 [success] Total time: 30 s, completed 20-nov-2015 9:59:48
14. SBT Console > android:run …. [info] Generating dex, incremental=false, multidex=true [info] dex method count: 79628 [info] Packaged: scala-sample-debug-unaligned.apk (7,08MB) [info] Debug package does not need signing: scala-sample-debug-unaligned.apk [info] zipaligned: scala-sample-debug.apk [info] Installing to Nexus 4 (047d6953d08fa35b)... [info] [scala-sample-debug.apk] Install finished: 7,09MB in 26,69s. 271,86KB/s [info] Running on Nexus 4 (047d6953d08fa35b)... [info] Starting: Intent { cmp=com.fortysevendeg.scala/com.fortysevendeg.scala.launcher.Activity } [success] Total time: 97 s, completed 20-nov-2015 9:52:48
15. SBT Console > devices [info] Serial Model Battery % Android Version [info] ---------------------- ---------------- ------------- -------------- [info] * oquoe2avnooz1my5 Nexus 4 76% 5.1.1 API 22 [info] 192.168.57.101:5555 Google Nexus S - 4.1.1 95% 4.1.1 API 16 > device oquoe2avnooz1my5 [info] default device: oquoe2avnooz1my5
16. android.Plugin.androidBuild // Specifying the Android target Sdk version platformTarget in Android := "android-22" // Application Name name := """scala-android-sample""" // Application Version version := "1.0.0" // Scala version scalaVersion := "2.11.7" SBT Configuration
17. // Override the run task with the android:run run <<= run in Android proguardScala in Android := true useProguard in Android := true proguardOptions in Android ++= Seq( "-ignorewarnings", "-keep class scala.Dynamic") SBT Configuration
18. libraryDependencies ++= Seq( aar("com.android.support" % "appcompat-v7" % "23.0.1"), aar("com.android.support" % "recyclerview-v7" % "23.0.1"), "com.google.android" % "android" % "4.1.1.4" % "test", "org.specs2" %% "specs2-core" % "3.6.5" % "test", "org.specs2" %% "specs2-mock" % "3.6.5" % "test") // Repositories for dependencies resolvers ++= Seq(Resolver.mavenLocal, DefaultMavenRepository, Resolver.typesafeRepo("releases"), Resolver.defaultLocal, "Scalaz Bintray Repo" at "http://dl.bintray.com/scalaz/releases" ) SBT Configuration
20. Google says: If you have been using Eclipse with ADT, be aware that Android Studio is now the official IDE for Android
21. Libraries MACROID SCALOID
22. Scaloid Features Easy to use & Compatible with your legacy code UI Layout without XML Asynchronous task processing More … [ https://github.com/pocorall/scaloid ]
23. Scaloid //plain vanilla scala val button = new Button(context) button.setText("Greet") button.setOnClickListener(new OnClickListener() { def onClick(v: View) = { Toast.makeText(context, "Hello!", Toast.LENGTH_SHORT).show() } }) layout.addView(button)
24. Scaloid //with Scaloid SButton("Greet", toast("Hello!"))
25. Macroid Features DSL focused to GUI Intensive use of Macros Brings the Functional Programming on Ui More … [ http://macroid.github.io ]
26. Macroid - Layouts getUi { l[LinearLayout]( w[Button], w[TextView] <~ text(“Hi!”) ) } <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent"> <Button android:layout_width="match_parent" android:layout_height="wrap_content" /> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Hi!"/> </LinearLayout>
27. but ... Awesome
28. XML Layouts 100% compatible with Macroid Works Great! Mandatory for some features in Android Design Libs
29. Android Contexts Can be derived from Application, Activities and Services Give access to Resources, Device Status… Singletons and life cycle attached Needed for a broad range of operations!
30. class MyActivity extends AppCompatActivity with Contexts[Activity] { override def onCreate(bundle: Bundle) = { ToastOps.showMessage("Implicits are awesome!") } } object ToastOps { def showMessage(msg: String)(implicit c: ContextWrapper) = Toast.makeText(c.bestAvailable, msg, Toast.LENG_SHORT).show() } Macroid - Using implicits
32. Macroid - Tweaks Add styles and behaviours to your widgets textView <~ text("Hi") textView <~ text("Hi") <~ show def textAndShow(str: String): Tweak[TextView] = text(str) + show textView <~ textAndShow("Hi")
33. Macroid - Custom Tweaks Create your own tweaks def myTweak(str: String) = Tweak[TextView] { tv => tv.setText(str) tv.setTypeface(tv.getTypeface(), Typeface.BOLD) } textView <~ myTweak("My Bold Text")
34. Slide sponsored by https://github.com/47deg/macroid-extras macroid-extras Lib
35. Macroid - Snails textView <~~ fadeIn textView <~~ fadeIn <~~ fadeOut editText <~ text("foo") <~~ fadeIn <~ enable Add animations to your views
36. Macroid - Transformers val imagesOnly = Transformer { case i: ImageView ⇒ i <~ show case x: View ⇒ x <~ hide } rootLayout <~ imagesOnly Scala pattern matching to alter layouts in a flexible way
37. Scala on Android Developer A day in the life of a
38. Compile and Run Slower (Scala Compiler + Proguard) Better Build Tool Easier to extend Tip: Take your time to setup your SBT
39. specs2 & scalacheck Android SDK and Genymotion Friendly CI & Codacy Tests and debug
40. The power of Scala
41. Scala Days Official App https://github.com/47deg/scala-days-android
42. Scala Api Demos https://github.com/47deg/scala-android
43. Translate Bubble https://github.com/47deg/translate-bubble-android
44. Other Projects https://github.com/47deg/scala-android-training Scala on Android Training https://github.com/47deg/functional-views-android Functional Views on Android
45. QUESTIONS?
46. THANK YOU