Kotlin Multiplatform Intro

Introduction to Kotlin Multiplatform, at Oredev.

Transcript

1. Kotlin Multiplatform Intro Kevin Galligan
2. Touchlab
4. What is Kotlin Multiplatform?
5. kot·lin mul·ti·plat·form /ˌkätˈlin məltiˈplatfôrm,ˌkätˈlin məltīˈplatfôrm/ noun noun: kotlin multiplatform 1.optional, natively-integrated, open-source, code sharing platform, based on the popular, modern language kotlin. facilitates non-ui logic availability on many platforms.
6. kot·lin mul·ti·plat·form /ˌkätˈlin məltiˈplatfôrm,ˌkätˈlin məltīˈplatfôrm/ noun noun: kotlin multiplatform 1.optional, natively-integrated, open-source, code sharing platform, based on the popular, modern language kotlin. facilitates non-ui logic availability on many platforms. Oh, and JetBrains!
7. Optional Sharing Low risk. No Big Decisions.
8. Natively Integrated smooth interop
9. open source
10. Code Sharing not “cross platform”
11. popular
12. popular
13. popular
14. modern
15. Not UI well, not necessarily UI
16. -Kevin Galligan “Shared UI is a history of pain and failure. Shared logic is the history of computers.”
17. Many Platforms
18. Common JVM JS Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android Browser Node
19. IDE and Tooling JetBrains makes it
20. Why Kotlin? High Efficiency Low Risk Modern Language/Tools Highly Engaged Community
21. mobile is easy
22. mobile is easy
23. Technically, Though what is it?
24. Common JVM JS Native
25. Common JVM JS Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android Browser Node
26. Common JVM JS Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android Browser Node
27. Common JVM JS Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android Browser Node
28. Common JVM JS Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android Browser Node
29. Common JVM JS Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android Browser Node
30. Common JVM Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android
31. Common JVM Native
32. Common JVM Native
33. Common JVM Native iOS
34. Common JVM iOS
35. Common JVM iOS Framework
36. Common JVM iOS Framework Android
37. Common Android iOS Framework
38. Common Android iOS Framework Android Stuff iOS Stuff
39. Status
40. Q3 Q2 Q4 Q1 Q2 2018 2019 v0.7 v0.8 v0.8.2 v0.9.3 IDE tooling! Coroutines? K/N 1.0, Kotlin 1.3 Gradle 4.10+ Android Studio Compiler plugins! Other samples/libraries Production deployments Paid license/debugger Reactive Library Big Production Apps Webassembly stuff? MT Coroutines!
41. Q3 Q2 Q4 Q1 Q2 2019 2020 v1.3.30 v1.3.40 v1.3.50 v1.3.60? MT Coroutines? Many Threading Libraries Many Threading Blog Posts Increased Production Adoption Improved Tooling Stability Compiler Plugins? Date/Time?
42. Q3 Q2 Q4 Q1 Q2 2019 2020 v1.3.30 v1.3.40 v1.3.50 v1.3.60? MT Coroutines? Mainstream Date/Time?
43. Is This Ready? that’s more about your team
44. Multithreaded Coroutines need to change my slides
45. Sharing Code
46. Kotlin Embraces “Native” the interop story is really good
47. expect/actual
48. //In common code expect val isMainThread: Boolean
49. //In common code expect val isMainThread: Boolean //In Android/JVM actual val isMainThread: Boolean get() = Looper.getMainLooper() === Looper.myLooper()
50. //In common code expect val isMainThread: Boolean //In Android/JVM actual val isMainThread: Boolean get() = Looper.getMainLooper() === Looper.myLooper() //In iOS/native code actual val isMainThread: Boolean get() = NSThread.isMainThread()
51. //Value expect val isMainThread: Boolean
52. //Value expect val isMainThread: Boolean //Function expect fun myFun():String
53. //Value expect val isMainThread: Boolean //Function expect fun myFun():String //Class expect class MyClass { fun heyo(): String }
54. //Value expect val isMainThread: Boolean //Function expect fun myFun():String //Class expect class MyClass { fun heyo(): String } //Object expect object MyObject { fun heyo(): String }
55. //Value expect val isMainThread: Boolean //Function expect fun myFun():String //Class expect class MyClass { fun heyo(): String } //Object expect object MyObject { fun heyo(): String } //Annotation @Target(AnnotationTarget.FUNCTION, AnnotationTarget.CONSTRUCTOR) @Retention(AnnotationRetention.SOURCE) expect annotation class Throws(vararg val exceptionClasses: KClass<out Throwable>)
56. expect class Sample() { fun checkMe(): Int } expect object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}"
57. actual class Sample { actual fun checkMe() = 44 } actual object Platform { actual val name: String = "Android" }
58. actual class Sample { actual fun checkMe() = 7 } actual object Platform { actual val name: String = "iOS" }
59. actual typealias with great power…
60. /** * Multiplatform AtomicInt implementation */ expect class AtomicInt(initialValue: Int) { fun get(): Int fun set(newValue: Int) fun incrementAndGet(): Int fun decrementAndGet(): Int fun addAndGet(delta: Int): Int fun compareAndSet(expected: Int, new: Int): Boolean }
61. JVM Side?
62. import java.util.concurrent.atomic.AtomicInteger actual typealias AtomicInt = AtomicInteger
63. Actual needs to match because obviously it does
64. import kotlin.native.concurrent.AtomicInt actual class AtomicInt actual constructor(initialValue:Int){ private val atom = AtomicInt(initialValue) actual fun get(): Int = atom.value actual fun set(newValue: Int) { atom.value = newValue } actual fun incrementAndGet(): Int = atom.addAndGet(1) actual fun decrementAndGet(): Int = atom.addAndGet(-1) actual fun addAndGet(delta: Int): Int = atom.addAndGet(delta) actual fun compareAndSet(expected: Int, new: Int): Boolean = atom.compareAndSet(expected, new) }
65. import kotlin.native.concurrent.AtomicInt actual class AtomicInt actual constructor(initialValue:Int){ private val atom = AtomicInt(initialValue) actual fun get(): Int = atom.value actual fun set(newValue: Int) { atom.value = newValue } actual fun incrementAndGet(): Int = atom.addAndGet(1) actual fun decrementAndGet(): Int = atom.addAndGet(-1) actual fun addAndGet(delta: Int): Int = atom.addAndGet(delta) actual fun compareAndSet(expected: Int, new: Int): Boolean = atom.compareAndSet(expected, new) }
66. library talk
67. Prefer Interfaces for “service” objects
68. public interface Settings { public fun clear() public fun remove(key: String) public fun hasKey(key: String): Boolean public fun putInt(key: String, value: Int) public fun getInt(key: String, defaultValue: Int = 0): Int public fun getIntOrNull(key: String): Int? public fun putLong(key: String, value: Long) public fun getLong(key: String, defaultValue: Long = 0): Long public fun getLongOrNull(key: String): Long? //Etc... } from https://github.com/russhwolf/multiplatform-settings
69. expect fun platformSettings():Settings
70. object ServiceRegistry { var sessionizeApi:SessionizeApi by ThreadLocalDelegate() var analyticsApi: AnalyticsApi by FrozenDelegate() var notificationsApi:NotificationsApi by FrozenDelegate() var dbDriver: SqlDriver by FrozenDelegate() var cd: CoroutineDispatcher by FrozenDelegate() var appSettings: Settings by FrozenDelegate() var concurrent: Concurrent by FrozenDelegate() var timeZone: String by FrozenDelegate() //Etc… from https://github.com/touchlab/DroidconKotlin/
71. Just an Interface no expect/actual required
72. class TestSettings:Settings { private val map = frozenHashMap<String, Any?>() override fun clear() { map.clear() } override fun getBoolean(key: String, defaultValue: Boolean): Bo return if(map.containsKey(key)){ map[key] as Boolean }else{ defaultValue } } //Etc… from https://github.com/touchlab/DroidconKotlin/
73. object ServiceRegistry { var sessionizeApi:SessionizeApi by ThreadLocalDelegate() var analyticsApi: AnalyticsApi by FrozenDelegate() var notificationsApi:NotificationsApi by FrozenDelegate() var dbDriver: SqlDriver by FrozenDelegate() var cd: CoroutineDispatcher by FrozenDelegate() var appSettings: Settings by FrozenDelegate() var concurrent: Concurrent by FrozenDelegate() var timeZone: String by FrozenDelegate() //Etc… from https://github.com/touchlab/DroidconKotlin/
74. koin multiplatform
75. interface AnalyticsApi { fun logEvent(name: String, params: Map<String, Any>) }
76. class AnalyticsApiImpl(val firebaseAnalytics: FirebaseAnalytics) : AnalyticsApi { override fun logEvent(name: String, params: Map<String, Any>) { val bundle = Bundle() params.keys.forEach { key -> when (val obj = params[key]) { is String -> bundle.putString(key, obj) is Int -> bundle.putInt(key, obj) else -> { throw IllegalArgumentException(“…”) } } } firebaseAnalytics.logEvent(name, bundle) } }
77. class AnalyticsApiMock : AnalyticsApi { var logCalled = false override fun logEvent(name: String, params: Map<String, Any>) { logCalled = true } }
78. class FirebaseAnalyticsApi: AnalyticsApi{ func logEvent(name: String, params: [String : Any]) { Analytics.logEvent(name, parameters: params) } }
79. serviceRegistry.doInitLambdas(staticFileLoader: loadAsset, clLogCallback: csLog, softExceptionCallback: softExceptionCallback) serviceRegistry.doInitServiceRegistry(sqlDriver: …, coroutineDispatcher: UI(), settings: FunctionsKt.defaultSettings(), concurrent: MainConcurrent(), sessionizeApi: SessionizeApiImpl(), analyticsApi: …, notificationsApi: NotificationsApiImpl(), timeZone: timeZone) AppContext().doInitAppContext(networkRepo: NetworkRepo(), fileRepo: FileRepo(), serviceRegistry: serviceRegistry, dbHelper: SessionizeDbHelper(), notificationsModel: NotificationsModel())
80. Function args! swift friendly
81. fun initLambdas( staticFileLoader: (filePrefix: String, fileType: String) -> String?, clLogCallback: (s: String) -> Unit, softExceptionCallback: (e:Throwable, message:String) - >Unit)
82. func loadAsset(filePrefix:String, fileType:String) -> String?{ do{ let bundleFile = Bundle.main.path(forResource: filePrefix, ofType: fileType) return try String(contentsOfFile: bundleFile!) } catch { return nil } }
83. Hard(er) to test tests are Kotlin exe
84. go.touchlab.co/dcktsrc
85. go.touchlab.co/dcktsrc
86. So no expect/actual? um…
87. Minimize expect/actual Droidcon App: 9 functions, 2 classes
88. Minimize expect/actual? Firestore SDK: 100+ ‘expect’ instances
89. Getting Started
90. Droidcon is OK there’s a lot going on, though
91. JetBrains Doc kotlinlang.org/docs/reference/building-mpp-with-gradle.html
92. “5 minutes” go.touchlab.co/kmp5
93. Kotlin Slack https://kotlinlang.org/community/
94. KMP evaluation kit
95. KaMP-Kit go.touchlab.co/KaMP-Kit
96. Concurrency it’s complicated (with native)
97. Two Rules mutable = 1 thread/immutable = many threads
98. Frozen new state of state
99. public fun <T> T.freeze(): T {...}
100. public fun <T> T.freeze(): T {...}
101. JetBrains Links • https://github.com/JetBrains/kotlin-native/blob/ master/IMMUTABILITY.md • https://github.com/JetBrains/kotlin-native/blob/ master/CONCURRENCY.md • https://www.youtube.com/watch?v=nw6YTfEyfO0
102. go.touchlab.co/knthreads
103. Kotlinconf
104. Thanks! @kpgalligan touchlab.co
105. Thanks! @kpgalligan touchlab.co Join the team !