Architecting a Kotlin multiplatform project

Transcript

1. FELIPE LIMA / OCT 4TH, 2018 / KOTLINCONF Architecting a Kotlin JVM and JS multiplatform project
2. FELIPE LIMA / OCT 4TH, 2018 / KOTLINCONF Architecting a Kotlin JVM and JS multiplatform project
3. INTRODUCTION
4. • Yet another cross platform framework? • Not all of them are created equal • Several options: React Native, Flutter, Xamarin, PhoneGap, Titanium, Cordova, etc. • Quite unlike all other options • Ideal for business logic code sharing How it works
6. Kotlin Multiplatform ≠ React Native TO MAKE IT CLEAR
7. Kotlin Multiplatform > C/C++ TO MAKE IT CLEAR
8. Common JVM Kotlin/Native Javascript Android
9. Common Kotlin/Native kotlinc kotlin2js
10. Common Kotlin/Native JVM kotlinc Android kotlin2js
11. Common Kotlin/Native Dynamic lib iOS Executable JVM kotlinc Android kotlin2js
12. A Common Kotlin/Native Dynamic lib iOS Executable JVM kotlinc Android kotlin2js Javascript
13. apply plugin: 'kotlin-platform-common' Gradle plugins
14. apply plugin: ‘kotlin-platform-android' Gradle plugins
15. apply plugin: ‘kotlin-platform-jvm’ Gradle plugins
16. apply plugin: ‘kotlin-platform-js’ Gradle plugins
17. apply plugin: ‘konan’ Gradle plugins
18. apply plugin: ‘org.jetbrains.kotlin.frontend’ Gradle plugins
19. dependencies { expectedBy project(':common') } Declaring dependencies
20. KEY CONCEPTS
21. L expect Shared module actual Platform module
22. expect class Order { val id: Int val userId: Int val amount: Decimal val feePercent: Decimal val price: Decimal val coinPair: CoinPair val status: OrderStatus val type: OrderType } Common
23. actual data class Order( actual val id: Int, actual val userId: Int, actual val amount: Decimal, actual val feePercent: Decimal, actual val price: Decimal, actual val coinPair: CoinPair, actual val status: OrderStatus, actual val type: OrderType, val createdAt: DateTime = DateTime.now(), val updatedAt: DateTime = DateTime.now() ) JVM
24. expect class Decimal Common
25. actual typealias Decimal = BigDecimal JVM
26. actual typealias Decimal = Double JS
27. expect fun currentTimeMs(): Long Common
28. actual fun currentTimeMs(): Long { return System.currentTimeMillis() } JVM
29. actual fun currentTimeMs(): Long { memScoped { val now = alloc<timeval>() gettimeofday(now.ptr, null) return (now.tv_sec.toLong() * 1000) + (now.tv_usec.toLong() / 1000) } } Kotlin/Native
30. • Simpler implementation (no factory classes or dep. injection) • Interfaces cannot have constructors • All implementations are known at compile time • More flexibility • Top level and extension functions are supported Why not interfaces?
31. • Cannot reference any platform specific code • Can only have Kotlin code • Can only depend on other Kotlin common modules or libraries Common module LIMITATIONS AND CAVEATS
32. DEEP DIVE
33. Story time
38. Console APU PPU CPU Mapper Audio buffer Video buffer Audio device Video device
39. Console APU PPU CPU Mapper Audio buffer Video buffer Audio device Video device
40. PPU Bitmap OpenGL ES GLSurfaceView
41. expect class Bitmap constructor( width: Int, height: Int ) { fun setPixel(x: Int, y: Int, value: Int) }
42. package android.graphics; public final class Bitmap implements Parcelable { // ... }
43. typealias AndroidBitmap = android.graphics.Bitmap actual class Bitmap actual constructor(width: Int, height: Int) { private val delegate: AndroidBitmap = AndroidBitmap.createBitmap(width, height, RGB_565) actual fun setPixel(x: Int, y: Int, value: Int) { delegate.setPixel(x, y, value) } }
44. actual typealias Bitmap = android.graphics.Bitmap
45. PPU IntArray OpenGL ES GLSurfaceView
46. internal class PPU( internal var buffer: IntArray = IntArray(IMG_WIDTH * IMG_HEIGHT) // ... }
47. KEY TAKE AWAYS
48. • Support is still experimental, expect rough edges and breaking changes • Very exciting technology • Benefits from a large and quickly growing Kotlin community • Expect the usual top notch tooling support by Jetbrains • You can start trying it out using it right now Key take aways
49. • Makes no assumptions about your system architecture • Not a framework, just a platform • Has the potential to turn into an entire ecosystem • Probably will require bigger organizational changes Key take aways
50. THANK YOU!