Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Challenges of Building Kotlin Multiplatform Lib...
Search
Mohit S
March 25, 2022
Programming
1
450
Challenges of Building Kotlin Multiplatform Libraries
Mohit S
March 25, 2022
Tweet
Share
More Decks by Mohit S
See All by Mohit S
Guide to Improving Compose Performance
heyitsmohit
0
250
Building Shared UIs across Platforms with Compose
heyitsmohit
1
650
Building Multiplatform Apps with Compose
heyitsmohit
2
530
Building StateFlows with Jetpack Compose
heyitsmohit
6
1.9k
Building Android Testing Infrastructure
heyitsmohit
1
510
Migrating to Kotlin State & Shared Flows
heyitsmohit
1
800
Using Square Workflow for Android & iOS
heyitsmohit
1
440
Building Android Infrastructure Teams at Scale
heyitsmohit
3
340
Strategies for Migrating to Jetpack Compose
heyitsmohit
2
580
Other Decks in Programming
See All in Programming
Writing Better Go: Lessons from 10 Code Reviews
konradreiche
3
6.8k
Things You Thought You Didn’t Need To Care About That Have a Big Impact On Your Job
hollycummins
0
260
コード生成なしでモック処理を実現!ovechkin-dm/mockioで学ぶメタプログラミング
qualiarts
0
270
Webサーバーサイド言語としてのRustについて
kouyuume
1
4.9k
CSC509 Lecture 06
javiergs
PRO
0
270
contribution to astral-sh/uv
shunsock
0
540
bootcamp2025_バックエンド研修_WebAPIサーバ作成.pdf
geniee_inc
0
130
Building, Deploying, and Monitoring Ruby Web Applications with Falcon (Kaigi on Rails 2025)
ioquatix
4
2.5k
組込みだけじゃない!TinyGo で始める無料クラウド開発入門
otakakot
2
380
エンジニアインターン「Treasure」とHonoの2年、そして未来へ / Our Journey with Hono Two Years at Treasure and Beyond
carta_engineering
0
430
Software Architecture
hschwentner
6
2.3k
技術的負債の正体を知って向き合う
irof
0
260
Featured
See All Featured
Making Projects Easy
brettharned
120
6.4k
Keith and Marios Guide to Fast Websites
keithpitt
411
23k
Site-Speed That Sticks
csswizardry
13
930
Automating Front-end Workflow
addyosmani
1371
200k
Being A Developer After 40
akosma
91
590k
Making the Leap to Tech Lead
cromwellryan
135
9.6k
[RailsConf 2023 Opening Keynote] The Magic of Rails
eileencodes
31
9.7k
[Rails World 2023 - Day 1 Closing Keynote] - The Magic of Rails
eileencodes
37
2.6k
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
658
61k
Building a Modern Day E-commerce SEO Strategy
aleyda
44
7.8k
Helping Users Find Their Own Way: Creating Modern Search Experiences
danielanewman
30
2.9k
The Language of Interfaces
destraynor
162
25k
Transcript
Mohit Sarveiya Building Kotlin Multiplatform Libraries @heyitsmohit
Building Kotlin Multiplatform Libraries • Setting up KMM project •
CI Challenges • API Design Challenges
Why Kotlin Multiplatform? Android Kotlin/JVM iOS Swift/LLVM Web JS
Why Kotlin Multiplatform? API API API
Why Kotlin Multiplatform? Retrofit Ajax Alamofire
Why Kotlin Multiplatform? Room/SQL Delight Core Data
Why Kotlin Multiplatform? Business Logic Business Logic Business Logic
Why Kotlin Multiplatform? MVP/MVVM/MVI ReactJs VIPER
Why Kotlin Multiplatform? Shared code
Why Kotlin Multiplatform? API Business Logic Analytics Cache
Setting up KMM Project
Use Case Show platform name Hello Android
Hello iOS Use Case 9:41 Show platform name
Greeter Use Case
How to create Multiplatform app
Plugin https: // plugins.jetbrains.com/plugin/14936-kotlin-multiplatform-mobile
Project Setup Shared
Project Setup Shared Android App
Project Setup Shared Android App iOS App XCode Project
Project Setup Shared Android App iOS App
Project Setup Shared Android App iOS App Framework
Project Setup Shared Android App iOS App
Shared Module Structure
Shared Module Shared src commonMain
Shared Module Shared src commonMain androidMain
Shared Module Shared src commonMain androidMain iOSMain
Greeter Use Case
Common Shared Module Android iOS Platform name
Common expect class Platform() { val platform: String }
Common expect class Platform() { val platform: String }
Common expect class Platform() { val platform: String }
Common expect class Platform() { val platform: String } Common
Common Android Android iOS Platform name
Android actual class Platform actual constructor() { actual val platform:
String = ”Android” }
Android actual class Platform actual constructor() { actual val platform:
String = ”Android” }
Android actual class Platform actual constructor() { actual val platform:
String = ”Android” }
Android actual class Platform actual constructor() { actual val platform:
String = ”Android” } Common Android
Common iOS Android iOS Platform name
iOS actual class Platform actual constructor() { actual val platform:
String = “iOS” }
Common Shared Module Android iOS Platform name
Common class Greeter { fun greet(): String { return "Hello
${Platform().platform}!" } }
Common class Greeter { fun greet(): String { return "Hello
${Platform().platform}!" } }
Using Shared Module
Project Setup Shared Android App iOS App
Use Case Show platform name Hello Android
Android App class MainActivity : AppCompatActivity() { }
Android App class MainActivity : AppCompatActivity() { fun onCreate( ...
) { val greeting = Greeter().greet() } }
Android App class MainActivity : AppCompatActivity() { fun onCreate( ...
) { val greeting = Greeter().greet() textView.text = greeting } }
Android App class Greeter { ... } Common Source Build
Use Case Hello Android
Android App class MainActivity : AppCompatActivity() { fun onCreate( ...
) { val greeting = Greeter().greet() textView.text = greeting } }
Hello iOS Use Case 9:41 Show platform name
iOS App class Greeter { ... } Common Source Build
Framework
iOS App import SwiftUI import shared
iOS App import SwiftUI import shared func greet() -> String
{ return Greeting().greeting() }
iOS App import SwiftUI import shared struct ContentView: View {
var body: some View { } }
iOS App import SwiftUI import shared struct ContentView: View {
var body: some View { Text(greet()) } }
Hello iOS Use Case 9:41 Show platform name
Inside Objective-C Framework
iOS Framework class Greeter { ... } Common Source Build
Framework
iOS Framework import SwiftUI import shared func greet() -> String
{ return Greeting().greeting() }
iOS Framework Shared Base Shared Platform Shared Greeting
Shared Base __attribute__((swift_name("KotlinBase"))) @interface SharedBase : NSObject ... @end;
Shared Base __attribute__((swift_name("KotlinBase"))) @interface SharedBase : NSObject ... @end;
iOS actual class Platform actual constructor() { actual val platform:
String = “iOS” }
Mappings https: // kotlinlang.org/docs/native-objc-interop.html#mappings
Shared Platform __ attribute __ ((swift_name(“Platform"))) @interface SharedPlatform : SharedBase
... @end;
Shared Platform __ attribute __ ((swift_name(“Platform"))) @interface SharedPlatform : SharedBase
@property (readonly) NSString *platform @end;
Common class Greeter { fun greet(): String { return "Hello
${Platform().platform}!" } }
Common @interface SharedGreeting : SharedBase - (NSString *)greeting __ attribute
__ ((swift_name("greeting()"))); @end;
Android & iOS Shared Modules
Use Case Hello Android 29
Shared Module Shared src commonMain androidMain iOSMain
Android actual class Platform actual constructor() { actual val platform:
String = “Android ${android.os.Build.VERSION.SDK_INT}" }
Hello iOS 14.4 Use Case 9:41
Shared Module Shared src commonMain androidMain iOSMain
iOS import platform.UIKit.UIDevice actual class Platform actual constructor() { actual
val platform: String = UIDevice.currentDevice.systemName() + " " + UIDevice.currentDevice.systemVersion }
iOS import platform.UIKit.UIDevice actual class Platform actual constructor() { actual
val platform: String = UIDevice.currentDevice.systemName() + " " + UIDevice.currentDevice.systemVersion }
Summary • How to build KMM project • Shared Module
Setup • Inside Shared Framework
CI Challenges
Swift Package Manager
Framework KMM Library
Swift Package Manager KMM Library
Multiplatform Swift Package • Gradle plugin • Generate XCFramework
Multiplatform Swift Package id("com.chromaticnoise.multiplatform-swiftpackage") version "2.0.3"
Multiplatform Swift Package multiplatformSwiftPackage { swiftToolsVersion(“5.5") targetPlatforms { iOS {
v("13") } } }
Multiplatform Swift Package ./gradlew createSwiftPackage
KMM Library XCEFramework
Projects/KMMProject Code ! Issues Pull Requests KMMLibrary.xcframework 1 commit 4c28f942
13 hours ago Package.swift KMMLibrary-1.0.zip README.md
Choose Package Repository Search or enter package repository URL Name
Last Updated Owner Projects(Github) KMMPackage Today 13:00 user
Add Package to Project Choose package and targets Kind Add
to Target KMMLibrary Library TestKMMLibrary Package Product
Steps • Create XCEFramework • Consume using Swift Package Manager
Build Automation
KMM Library bdae142 .. main 50157a .. d89f145 .. f0ddfb
..
bdae142 .. main 50157a .. d89f145 .. f0ddfb ..
KMM Library Jar XCEFramework
KMM Library Jar XCEFramework Artifactory
Artifactory
Build Automation • Setup CI to create artifcats • Use
artifacts from repository like Artifactory
API Design Challenges
Flows
Common fun getData(): Flow<Data>
Android val flow = getData() flow.collect { }
iOS getData( collector: T ## Kotlinx_coroutines_coreFlowCollector, completionHandler: (KotlinUnit?, Error?) ->
Void )
Common class CFlow internal constructor( val origin: Flow ) :
Flow by origin { fun watch(block: (T) -> Unit) { } }
Common class CFlow internal constructor( val origin: Flow ) :
Flow by origin { fun watch(block: (T) -> Unit) { onEach { block(it) } launchIn(CoroutineScope( ... )) } }
Common fun Flow<T>.wrap(): CFlow<T> = CFlow(this)
iOS flow .wrap() .watch { data -> }
Building Kotlin Multiplatform Libraries • Setting up KMM project •
CI Challenges • API Design Challenges
Thank You! www.codingwithmohit.com @heyitsmohit