Reuso de código com Kotlin Multiplataforma

Essa palestra visa apresentar o conceito de multiplataforma do Kotlin, com suas vantagens e desvantagens, e como esse conceito é diferente de soluções cross-platform no que tange a reuso de código entre plataformas. Por fim, será mostrado a aplicação desse conceito em um simples chat feito com kotlin para web, android e iOS.

Exemplos de Kotlin Multiplatform:
- https://github.com/felipehjcosta/hello-world-multiplatform
- https://github.com/felipehjcosta/marvel-client
- https://github.com/felipehjcosta/chat-app

Referências:
- https://touchlab.co/future-cross-platform-native/
- https://www.youtube.com/watch?v=c8IkWGmlcNE
- https://www.youtube.com/watch?v=Dul17VSiejo
- https://www.youtube.com/watch?v=nw6YTfEyfO0
- https://www.youtube.com/watch?v=pcwIs749KSE
- https://medium.com/xebia-france/understanding-the-basics-of-multiplatform-projects-in-kotlin-1-3-1221689b3084

Transcript

1. Reuso de código com Kotlin Multiplataforma
2. Felipe Costa Engenheiro de software Senior @ OLX Profissional de software apaixonado. Atuo como desenvolvedor, principalmente, para dispositivos móveis desde 2011 e fazendo- o principalmente em Kotlin desde 2016.
3. Nosso Propósito Aproximamos Brasileiros para transformar itens em felicidade.
4. Kotlin @ OLX 0 Python Javascript Java C PHP Kotlin Objective-C Perl
5. Kotlin @ OLX 0 Android Autenticação Experimentação inserção Busca Recomendação
6. Karol & MVP de um chat multiplataforma
7. Por quê reutilizar código entre plataformas?
8. DRY
9. Mitigação de risco
10. Paridade de funcionalidades
11. Soluções
12. Entrada Processo Saída Tipo de App Linguagem nativa: Kotlin & Swift & JS Outra linguagem Cross-Compilação Inclui Runtime (Interpretador, VM, Bibliotecas) Código nativo Linguagem nativa: Javascript Nativo Web Nativo Web
13. Entrada Processo Saída Tipo de app Linguagem nativa Outra linguagem: Javascript Cross-Compilação Inclui Runtime (Interpretador, VM, Bibliotecas) Código nativo + Bundle JS Linguagem nativa Nativo Web React Native
14. Flutter Entrada Processo Saída Tipo de app Linguagem nativa Outra linguagem: Dart Cross-Compilação Inclui Runtime (Interpretador, VM, Bibliotecas) Código nativo Linguagem nativa Nativo Web
15. Kotlin Multiplataforma Entrada Processo Saída Tipo de app Linguagem nativa: Kotlin Outra linguagem Cross-Compilação Inclui Runtime (Interpretador, VM, Bibliotecas) Código nativo Linguagem nativa: Javascript Nativo Web Android iOS Web
16. Por quê Kotlin Multiplataforma?
17. Compartilhamento opcional Baixo risco Sem Grandes decisões
18. 100% Nativo Interop suave
19. Compartilhamento de código Não é “cross plataforma”
20. Comunidade ativa
21. Boas ferramentas
22. Linguagem moderna
23. Sem UI não necessariamente
24. Muitas plataformas
25. Common *.kt
26. plugins { id 'kotlin-multiplatform' version '1.3.31' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
27. plugins { id 'kotlin-multiplatform' version '1.3.31' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
28. plugins { id 'kotlin-multiplatform' version '1.3.31' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
29. plugins { id 'kotlin-multiplatform' version '1.3.31' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
30. Common *.kt
31. Common *.kt *.class *.jar, *.apk
32. kotlin { jvm() sourceSets { commonMain { /* */ } } } Build.gradle
33. kotlin { jvm() sourceSets { commonMain { /* */ } } } Build.gradle
34. kotlin { jvm() sourceSets { commonMain { /* */ } } } Build.gradle
35. Common *.kt *.class *.jar, *.apk
36. Common *.kt *.class *.jar, *.apk *.js
37. kotlin { jvm() js() sourceSets { commonMain { /* */ } } } Build.gradle
38. kotlin { jvm() js() sourceSets { commonMain { /* */ } } } Build.gradle
39. kotlin { jvm() js() sourceSets { commonMain { /* */ } } } Build.gradle
40. Common *.kt *.class *.jar, *.apk *.js
41. Common *.kt *.class *.jar, *.apk *.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Outros
42. kotlin { jvm() js() // For ARM, should be changed to iosArm32 or iosArm64 // For Linux, should be changed to e.g. linuxX64 // For MacOS, should be changed to e.g. macosX64 // For Windows, should be changed to e.g. mingwX64 macosX64("macos") sourceSets { commonMain { /* */ } } } Build.gradle
43. kotlin { jvm() js() // For ARM, should be changed to iosArm32 or iosArm64 // For Linux, should be changed to e.g. linuxX64 // For MacOS, should be changed to e.g. macosX64 // For Windows, should be changed to e.g. mingwX64 macosX64("macos") sourceSets { commonMain { /* */ } } } Build.gradle
44. kotlin { jvm() js() // For ARM, should be changed to iosArm32 or iosArm64 // For Linux, should be changed to e.g. linuxX64 // For MacOS, should be changed to e.g. macosX64 // For Windows, should be changed to e.g. mingwX64 macosX64("macos") sourceSets { commonMain { /* */ } } } Build.gradle
45. fun hello(): String = "Hello from Kotlin Multiplatform" Common
46. import kotlin.Metadata; import org.jetbrains.annotations.NotNull; @Metadata( mv = {1, 1, 15}, bv = {1, 0, 3}, k = 2, d1 = {"\u0000\b\n\u0000\n\u0002\u0010\u000e\n\u0000\u001a\u0006\u0010\u0000\u001a\u00020\u0001¨\u0006\u0002"}, d2 = {"hello", "", "Platform module com.example.hello-world-multiplatform.jvmMain including [com.example.hello-world-multiplatform.commonMain]"} ) public final class SampleKt { @NotNull public static final String hello() { return "Hello from Kotlin Multiplatform"; } } JVM
47. if (typeof kotlin === 'undefined') { throw new Error("Error loading module 'hello-world-multiplatform'. Its dependency 'kotlin' was not found. Please, check whether 'kotlin' is loaded prior to 'hello-world-multiplatform'."); } this['hello-world-multiplatform'] = function (_, Kotlin) { 'use strict'; function hello() { return 'Hello from Kotlin Multiplatform'; } var package$sample = _.sample || (_.sample = {}); package$sample.hello = hello; Kotlin.defineModule('hello-world-multiplatform', _); return _; }(typeof this['hello-world-multiplatform'] === 'undefined' ? {} : this['hello-world-multiplatform'], kotlin); JS
48. MacOS Binary .kexe
49. kotlin { jvm() js() macosX64("macos") { binaries { sharedLib("sharedLib") } } sourceSets { commonMain { /* */ } } } Build.gradle
50. kotlin { jvm() js() macosX64("macos") { binaries { sharedLib("sharedLib") } } sourceSets { commonMain { /* */ } } } Build.gradle
51. kotlin { jvm() js() macosX64("macos") { binaries { sharedLib("sharedLib") } } sourceSets { commonMain { /* */ } } } Build.gradle
52. MacOS Dynamic Library #ifndef KONAN_LIBSHAREDLIB_H #define KONAN_LIBSHAREDLIB_H #ifdef __cplusplus extern "C" { #endif /* typedefes */ typedef struct { /* Service functions. */ /* ... */ /* User functions. */ struct { struct { struct { const char* (*hello)(); } sample; } root; } kotlin; } libsharedLib_ExportedSymbols; extern libsharedLib_ExportedSymbols* libsharedLib_symbols(void); #ifdef __cplusplus } /* extern "C" */ #endif #endif /* KONAN_LIBSHAREDLIB_H */
53. kotlin { jvm() js() macosX64("macos") { binaries { framework("framework") } } sourceSets { commonMain { /* */ } } } Build.gradle
54. kotlin { jvm() js() macosX64("macos") { binaries { framework("framework") } } sourceSets { commonMain { /* */ } } } Build.gradle
55. kotlin { jvm() js() macosX64("macos") { binaries { framework("framework") } } sourceSets { commonMain { /* */ } } } Build.gradle
56. MacOS Framework #import <Foundation/Foundation.h> NS_ASSUME_NONNULL_BEGIN @interface KotlinBase : NSObject - (instancetype)init __attribute__((unavailable)); + (instancetype)new __attribute__((unavailable)); + (void)initialize __attribute__((objc_requires_super)); @end; @interface KotlinBase (KotlinBaseCopying) <NSCopying> @end; /* More types */ __attribute__((objc_subclassing_restricted)) __attribute__((swift_name("SampleKt"))) @interface FrameworkSampleKt : KotlinBase + (NSString *)hello __attribute__((swift_name("hello()"))); @end; NS_ASSUME_NONNULL_END
57. fun hello(): String = "Hello from Kotlin Multiplatform" Common
58. object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
59. object Platform { val name: String = "JVM" } fun hello(): String = "Hello from ${Platform.name}" JVM
60. object Platform { val name: String = "JS" } fun hello(): String = "Hello from ${Platform.name}" JS
61. object Platform { val name: String = "Native" } fun hello(): String = "Hello from ${Platform.name}" Native
62. Common *.kt *.class *.jar, *.apk *.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Outros
63. Common *.kt Kotlin/JVM *.kt, *.java Kotlin/JS *.kt, *.js Kotlin/Native *.kt *.class *.jar, *.apk *.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Others
64. expect object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
65. expect object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
66. expect object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
67. kotlin { jvm() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { dependencies { implementation kotlin('stdlib-jdk8') } } } } build.gradle
68. kotlin { jvm() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { dependencies { implementation kotlin('stdlib-jdk8') } } } } build.gradle
69. kotlin { jvm() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { dependencies { implementation kotlin('stdlib-jdk8') } } } } build.gradle
70. actual object Platform { actual val name: String = "JVM" } fun hello(): String = "Hello from JVM" JVM
71. actual object Platform { actual val name: String = "JVM" } fun hello(): String = "Hello from JVM" JVM
72. actual object Platform { actual val name: String = "JVM" } fun hello(): String = "Hello from JVM" JVM
73. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { dependencies { implementation kotlin('stdlib-js') } } } } build.gradle
74. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { dependencies { implementation kotlin('stdlib-js') } } } } build.gradle
75. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { dependencies { implementation kotlin('stdlib-js') } } } } build.gradle
76. actual object Platform { actual val name: String = "JS" } fun hello(): String = "Hello from JS" JS
77. actual object Platform { actual val name: String = "JS" } fun hello(): String = "Hello from JS" JS
78. actual object Platform { actual val name: String = "JS" } fun hello(): String = "Hello from JS" JS
79. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { /* */ } macosMain { } } } build.gradle
80. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { /* */ } macosMain { } } } build.gradle
81. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { /* */ } macosMain { } } } build.gradle
82. actual object Platform { actual val name: String = "Native" } fun hello(): String = "Hello from Native” Native
83. actual object Platform { actual val name: String = "Native" } fun hello(): String = "Hello from Native” Native
84. actual object Platform { actual val name: String = "Native" } fun hello(): String = "Hello from Native” Native
85. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } commonTest { /* */ } jvmMain { /* */ } jvmTest { /* */ } jsMain { /* */ } jsTest { /* */ } macosMain { /* */ } macosTest { /* */ } } } build.gradle
86. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } commonTest { /* */ } jvmMain { /* */ } jvmTest { /* */ } jsMain { /* */ } jsTest { /* */ } macosMain { /* */ } macosTest { /* */ } } } build.gradle
87. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } commonTest { /* */ } jvmMain { /* */ } jvmTest { /* */ } jsMain { /* */ } jsTest { /* */ } macosMain { /* */ } macosTest { /* */ } } } build.gradle
88. kotlin { /* */ sourceSets { /* */ commonTest { dependencies { implementation kotlin('test-common') implementation kotlin('test-annotations-common') } } jvmTest { dependencies { implementation kotlin('test') implementation kotlin('test-junit') } } jsTest { dependencies { implementation kotlin('test-js') } } macosTest { } } } build.gradle
89. import kotlin.test.Test import kotlin.test.assertTrue class SampleTestsJVM { @Test fun testHello() { assertTrue("JVM" in hello()) } } JVM
90. import kotlin.test.Test import kotlin.test.assertTrue class SampleTestsJS { @Test fun testHello() { assertTrue("JS" in hello()) } } JS
91. import kotlin.test.Test import kotlin.test.assertTrue class SampleTestsNative { @Test fun testHello() { assertTrue("Native" in hello()) } } Native
92. expect class Sample() { fun checkMe(): Int } object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
93. import kotlin.test.Test import kotlin.test.assertTrue class SampleTests { @Test fun testMe() { assertTrue(Sample().checkMe() > 0) } } Common
94. Bibliotecas
95. Ktor Kotlinx.Coroutines kotlinx.io kotlinx.serialization sqldelight MPSettings Stately KorLibs Acesso a arquivos Melhor suporte a testes Data Estado de UI
96. MVP de um Chat Multiplataforma
97. Arquitetura Common Client Android iOS Web Server
98. Arquitetura Android iOS Web Server Main Common Message Client ChatViewModel ChatClient
99. Common ChatClient.kt Kotlin/JVM ChatClient.kt Kotlin/JS ChatClient.kt Kotlin/Native ChatClient.kt ChatClient.class ChatClient.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Outros
100. internal expect open class ChatClient(url: String) { open fun start() open fun send(message: Message) open fun receive(receiveBlock: (Message) -> Unit) open fun onFailure(throwableBlock: (Throwable) -> Unit) } Common
101. internal expect open class ChatClient(url: String) { open fun start() open fun send(message: Message) open fun receive(receiveBlock: (Message) -> Unit) open fun onFailure(throwableBlock: (Throwable) -> Unit) } Common
102. internal expect open class ChatClient(url: String) { open fun start() open fun send(message: Message) open fun receive(receiveBlock: (Message) -> Unit) open fun onFailure(throwableBlock: (Throwable) -> Unit) } Common
103. internal actual open class ChatClient actual constructor(val url: String) : WebSocketListener() { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } override fun onMessage(webSocket: WebSocket, text: String) { /* */ } override fun onFailure(webSocket: WebSocket, t: Throwable, response: Response?) { /* */ } } Android
104. internal actual open class ChatClient actual constructor(val url: String) : WebSocketListener() { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } override fun onMessage(webSocket: WebSocket, text: String) { /* */ } override fun onFailure(webSocket: WebSocket, t: Throwable, response: Response?) { /* */ } } Android
105. internal actual open class ChatClient actual constructor(val url: String) : WebSocketListener() { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } override fun onMessage(webSocket: WebSocket, text: String) { /* */ } override fun onFailure(webSocket: WebSocket, t: Throwable, response: Response?) { /* */ } } Android
106. internal actual open class ChatClient actual constructor(val url: String) { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } } JS
107. internal actual open class ChatClient actual constructor(val url: String) { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } } JS
108. internal actual open class ChatClient actual constructor(val url: String) { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } } JS
109. internal actual open class ChatClient actual constructor(val url: String) { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } inner class WebSocketDelegate : NSObject(), SRWebSocketDelegateProtocol { override fun webSocket(webSocket: SRWebSocket?, didReceiveMessage: Any?) { /* */ } } } iOS
110. internal actual open class ChatClient actual constructor(val url: String) { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } inner class WebSocketDelegate : NSObject(), SRWebSocketDelegateProtocol { override fun webSocket(webSocket: SRWebSocket?, didReceiveMessage: Any?) { /* */ } } } iOS
111. internal actual open class ChatClient actual constructor(val url: String) { actual open fun start() { /* */ } actual open fun send(message: Message) { /* */ } actual open fun receive(receiveBlock: (Message) -> Unit) { /* */ } actual open fun onFailure(throwableBlock: (Throwable) -> Unit) { /* */ } inner class WebSocketDelegate : NSObject(), SRWebSocketDelegateProtocol { override fun webSocket(webSocket: SRWebSocket?, didReceiveMessage: Any?) { /* */ } } } iOS
112. Demo
114. Desafios
115. Experimental
116. Threads
117. Debug
118. Tempo de compilação
119. MVP de Chat entregue
121. felipehjcosta felipe.costa@olxbr.com