Common
JVM JS Native
iOS Mac
Linux Windows
Android/NDK Wasm
Others…
Java-6 Java-8
Android
Browser
Node
Typescript(?)
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Kotlin Multiplatform Mobile
(KMM)
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KMM
•is mostly a branding designation (it’s still KMP)
•has a dedicated website and docs to help get started
•has an Android Studio plugin built just for mobile (ish)
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Why KMP/KMM?
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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.
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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!
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Shared Native Code
not “cross platform”
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Android is Kotlin
half of it isn’t “cross platform”
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Not (necessarily) UI
Compose and Swift UI compatible!
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Low Risk
bigger orgs worry about such
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Production!
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Who’s shipping?
Cash (Square), Plangrid, Careem,
Quizlet, Down Dog, Target,
VMWare, Wayfair, Clue, Skip the
Dishes
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mParticle
shipping a library generator
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Covid-related App
still in “need to know” status
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Getting Started
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https://kotlinlang.org/lp/mobile/
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github.com/touchlab/KaMPKit
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Production?
seems intro to me…
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Tooling
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Intellij
the safe choice
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Android Studio Plugin!
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Xcode Plugin
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All use lldb
deep in the weeds, but…
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Crash Reporting
CrashKiOS
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No content
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No content
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github.com/touchlab/CrashKiOS
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Package Managers
(here be dragons)
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JS Stuff
npm? Typescript?
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Libraries
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Check out KaMP KIt
mostly what we’re using in prod
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What’s missing?
bad news section
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expect class Date {
fun toLongMillis(): Long
}
expect class DateFormatHelper(format: String) {
fun toConferenceDate(s: String): Date
fun toLocalDate(s: String): Date
fun formatConferenceTZ(d: Date): String
fun formatLocalTZ(d: Date): String
}
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Great Time To Start!
still lots of stuff to make
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Integrating
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“Selling” KMP/KMM
not everybody loves it
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Start with Empathy
“Javascript can do everything!”
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Find Allies
iOS build config is difficult
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Modifying an iOS any prod build is tough
recruit the experts
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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!
not “cross platform”
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Pick Something Nobody Likes
few love core data
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“Selling” KMP/KMM Links
• Starter Kit: Kotlin Multiplatform (KMP) for iOS Developers
https://go.touchlab.co/kmpsell
• Introduce your team to KMM
https://kotlinlang.org/docs/mobile/introduce-your-team-to-
kmm.html
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Actually Integrating
what I thought this talk would be about
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Common
Android iOS
Framework
Android
Stuff
iOS
Stuff
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Greenfield
Common
Android iOS
Framework
Android
Stuff
iOS
Stuff
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Ship Binary
Common
Android iOS
Framework
Android
Stuff
iOS
Stuff
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Kotlin Xcode Plugin
intro to Kotlin for iOS devs
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Why not both?
Common
Android iOS
Framework
Android
Stuff
iOS
Stuff
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Big Topic
every team is different
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No content
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Assorted Info and “Bad News”
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Concurrency
it’s different, but changing
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Two Rules
one thread == mutable
many threads == immutable (frozen)
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That is Changing
realistically 2nd half of next year
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Your Code Won’t Change (much)
unless you do a lot of concurrency management
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Concurrency Links
• KMM Concurrency Overview
https://kotlinlang.org/docs/mobile/concurrency-overview.html
• Kotlin/Native Concurrency Handson
https://play.kotlinlang.org/hands-on/
Kotlin%20Native%20Concurrency/00_Introduction
• Thoughts on the changes
https://medium.com/@kpgalligan/kotlin-native-concurrency-
changes-bbb1a5147e6
• More deep dive video
https://www.youtube.com/watch?v=oxQ6e1VeH4M
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You must learn it
or wait till late 2021
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Kotlinx Coroutines
two libraries
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Ktor and iOS
https://medium.com/@kpgalligan/ktor-and-kotlin-native-fb5c06cb920a
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Simple Answer
Kotlin 1.4.* and MT coroutines
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Single Xcode Framework
this is a big one
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DB
KT
Framework
iOS
Stuff
Contacts
Products
Analytics
stdlib
Single Framework Links
• Multiple Kotlin Frameworks in an Application
https://touchlab.co/multiple-kotlin-frameworks-in-application/
• Kotlin team tickets
https://youtrack.jetbrains.com/issue/KT-42247
https://youtrack.jetbrains.com/issue/KT-42250
• Compiler Plugins
• Super-solid IDE and tooling support
• Post-alpha (GA maybe?)
• Proper WASM :)
• New memory model
• Way more library support (date format, file, mock, etc)
• Compose for iOS? (probably not, but at some point)