Reuso de código com Kotlin Multiplataforma @ KotlinConf Global 2019 - Curitiba

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 além de algumas referências.

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

Referências:
- https://touchlab.co/future-cross-platform-native/
- https://www.youtube.com/playlist?list=PLQ176FUIyIUY6SKGl3Cj9yeYibBuRr3Hl
- https://www.youtube.com/watch?v=c8IkWGmlcNE
- https://www.youtube.com/watch?v=nw6YTfEyfO0

Transcript

1. Reuso de código com Kotlin Multiplataforma KotlinConf Global 2019 - Curitiba
2. Felipe Costa Engenheiro de software sênior @ 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 Empoderar os brasileiros para realizarem seus sonhos, reinventando o modelo de consumo.
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 que 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 que Kotlin Multiplataforma?
17. Compartilhamento opcional Baixo risco Sem Grandes decisões
18. 100% Nativo Interoperabilidade suave Cidadão de primeira classe
19. Compartilhamento de código Não é “cross plataform”
20. Comunidade ativa
21. Boas ferramentas
22. Linguagem moderna
23. Sem a necessidade de UI Regras de negócio
24. Quem está usando?
28. Muitas plataformas
29. Common *.kt
30. plugins { id 'kotlin-multiplatform' version '1.3.61' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
31. plugins { id 'kotlin-multiplatform' version '1.3.61' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
32. plugins { id 'kotlin-multiplatform' version '1.3.61' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
33. plugins { id 'kotlin-multiplatform' version '1.3.61' } repositories { mavenCentral() } kotlin { sourceSets { commonMain { dependencies { implementation kotlin('stdlib-common') } } } } Build.gradle
34. Common *.kt
35. Common *.kt *.class *.jar, *.apk
36. kotlin { jvm() sourceSets { commonMain { /* */ } } } Build.gradle
37. kotlin { jvm() sourceSets { commonMain { /* */ } } } Build.gradle
38. kotlin { jvm() sourceSets { commonMain { /* */ } } } Build.gradle
39. Common *.kt *.class *.jar, *.apk
40. Common *.kt *.class *.jar, *.apk *.js
41. kotlin { jvm() js() sourceSets { commonMain { /* */ } } } Build.gradle
42. kotlin { jvm() js() sourceSets { commonMain { /* */ } } } Build.gradle
43. kotlin { jvm() js() sourceSets { commonMain { /* */ } } } Build.gradle
44. kotlin { jvm() js { browser() nodejs() } sourceSets { commonMain { /* */ } } } Build.gradle
45. kotlin { jvm() js { browser() nodejs() } sourceSets { commonMain { /* */ } } } Build.gradle
46. kotlin { jvm() js { browser() nodejs() } sourceSets { commonMain { /* */ } } } Build.gradle
47. Common *.kt *.class *.jar, *.apk *.js
48. Common *.kt *.class *.jar, *.apk *.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Outros
49. 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
50. 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
51. 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
52. fun hello(): String = "Hello from Kotlin Multiplatform" Common
53. 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
54. 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
55. MacOS Binary .kexe
56. kotlin { jvm() js() macosX64("macos") { binaries { sharedLib("SharedLib") } } sourceSets { commonMain { /* */ } } } Build.gradle
57. kotlin { jvm() js() macosX64("macos") { binaries { sharedLib("SharedLib") } } sourceSets { commonMain { /* */ } } } Build.gradle
58. kotlin { jvm() js() macosX64("macos") { binaries { sharedLib("SharedLib") } } sourceSets { commonMain { /* */ } } } Build.gradle
59. 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 */
60. kotlin { jvm() js() macosX64("macos") { binaries { framework("Framework") } } sourceSets { commonMain { /* */ } } } Build.gradle
61. kotlin { jvm() js() macosX64("macos") { binaries { framework("Framework") } } sourceSets { commonMain { /* */ } } } Build.gradle
62. kotlin { jvm() js() macosX64("macos") { binaries { framework("Framework") } } sourceSets { commonMain { /* */ } } } Build.gradle
63. 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
64. E plataformas específicas?
65. fun hello(): String = "Hello from Kotlin Multiplatform" Common
66. object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
67. object Platform { val name: String = "JVM" } fun hello(): String = "Hello from ${Platform.name}" JVM
68. object Platform { val name: String = "JS" } fun hello(): String = "Hello from ${Platform.name}" JS
69. object Platform { val name: String = "Native" } fun hello(): String = "Hello from ${Platform.name}" Native
70. Common *.kt *.class *.jar, *.apk *.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Outros
71. Common *.kt Kotlin/JVM *.kt, *.java Kotlin/JS *.kt, *.js Kotlin/Native *.kt, *.c *.class *.jar, *.apk *.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Others
73. Expect/Actual
74. expect object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
75. expect object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
76. expect object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
77. kotlin { jvm() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { dependencies { implementation kotlin('stdlib-jdk8') } } } } build.gradle
78. kotlin { jvm() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { dependencies { implementation kotlin('stdlib-jdk8') } } } } build.gradle
79. kotlin { jvm() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { dependencies { implementation kotlin('stdlib-jdk8') } } } } build.gradle
80. actual object Platform { actual val name: String = "JVM" } fun hello(): String = "Hello from JVM" JVM
81. actual object Platform { actual val name: String = "JVM" } fun hello(): String = "Hello from JVM" JVM
82. actual object Platform { actual val name: String = "JVM" } fun hello(): String = "Hello from JVM" JVM
83. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { dependencies { implementation kotlin('stdlib-js') } } } } build.gradle
84. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { dependencies { implementation kotlin('stdlib-js') } } } } build.gradle
85. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { dependencies { implementation kotlin('stdlib-js') } } } } build.gradle
86. actual object Platform { actual val name: String = "JS" } fun hello(): String = "Hello from JS" JS
87. actual object Platform { actual val name: String = "JS" } fun hello(): String = "Hello from JS" JS
88. actual object Platform { actual val name: String = "JS" } fun hello(): String = "Hello from JS" JS
89. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { /* */ } macosMain { } } } build.gradle
90. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { /* */ } macosMain { } } } build.gradle
91. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } jvmMain { /* */ } jsMain { /* */ } macosMain { } } } build.gradle
92. actual object Platform { actual val name: String = "Native" } fun hello(): String = "Hello from Native” Native
93. actual object Platform { actual val name: String = "Native" } fun hello(): String = "Hello from Native” Native
94. actual object Platform { actual val name: String = "Native" } fun hello(): String = "Hello from Native” Native
95. Testes?
96. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } commonTest { /* */ } jvmMain { /* */ } jvmTest { /* */ } jsMain { /* */ } jsTest { /* */ } macosMain { /* */ } macosTest { /* */ } } } build.gradle
97. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } commonTest { /* */ } jvmMain { /* */ } jvmTest { /* */ } jsMain { /* */ } jsTest { /* */ } macosMain { /* */ } macosTest { /* */ } } } build.gradle
98. kotlin { jvm() js() macosX64("macos") sourceSets { commonMain { /* */ } commonTest { /* */ } jvmMain { /* */ } jvmTest { /* */ } jsMain { /* */ } jsTest { /* */ } macosMain { /* */ } macosTest { /* */ } } } build.gradle
99. 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
100. import kotlin.test.Test import kotlin.test.assertTrue class SampleTestsJVM { @Test fun testHello() { assertTrue("JVM" in hello()) } } JVM
101. import kotlin.test.Test import kotlin.test.assertTrue class SampleTestsJS { @Test fun testHello() { assertTrue("JS" in hello()) } } JS
102. import kotlin.test.Test import kotlin.test.assertTrue class SampleTestsNative { @Test fun testHello() { assertTrue("Native" in hello()) } } Native
103. expect class Sample() { fun checkMe(): Int } object Platform { val name: String } fun hello(): String = "Hello from ${Platform.name}" Common
104. import kotlin.test.Test import kotlin.test.assertTrue class SampleTests { @Test fun testMe() { assertTrue(Sample().checkMe() > 0) } } Common
105. Bibliotecas
106. Ktor Kotlinx.Coroutines kotlinx.io kotlinx.serialization sqldelight MPSettings Stately KorLibs Acesso a arquivos Melhor suporte a testes Data Estado de UI
108. MVP de um Chat Multiplataforma
109. Arquitetura Common Client Android iOS Web Server
110. Arquitetura Android iOS Web Server Main Common Message Client ChatViewModel ChatClient
111. Common ChatClient.kt Kotlin/JVM ChatClient.kt Kotlin/JS ChatClient.kt Kotlin/Native ChatClient.kt *.class *.jar, *.apk *.js binário nativo Android/ NDK iOS Mac Linux Windows Webassembly Others
112. 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
113. 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
114. 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
115. 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
116. 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
117. 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
118. 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
119. 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
120. 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
121. 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) { /* */ } } iOS
122. 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) { /* */ } } iOS
123. 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) { /* */ } } iOS
124. Demo
126. Hands-on
127. Desafios
128. Experimental
129. Threads
130. Debug
131. Suporte de testes
132. Tempo de compilação
133. MVP de Chat entregue
135. felipehjcosta felipe.costa@olxbr.com