Kotlin Multiplatform in Production

Kotlin Multiplatform is steadily making its way into production applications. We (Touchlab) are working with a bunch of orgs to make that happen. This talk kind of wanders through a whole bunch of tangentially related topics. It also has a bunch of links.

Transcript

1. Kotlin Multiplatform in Production Kevin Galligan
2. Touchlab
4. Kotlin Multiplatform in Production hmm
5. What are KMP/KMM?
6. Kotlin Multiplatform (KMP)
7. Common JVM JS Native
8. It’s the interop generally very good
9. Common JVM JS Native
10. Common JVM JS Native iOS Mac Linux Windows Android/NDK Wasm Others… Java-6 Java-8 Android Browser Node Typescript(?)
11. Kotlin Multiplatform Mobile (KMM)
12. 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)
14. Why KMP/KMM?
15. 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.
16. 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!
17. Shared Native Code not “cross platform”
18. Android is Kotlin half of it isn’t “cross platform”
19. Not (necessarily) UI Compose and Swift UI compatible!
20. Low Risk bigger orgs worry about such
21. Production!
22. Who’s shipping? Cash (Square), Plangrid, Careem, Quizlet, Down Dog, Target, VMWare, Wayfair, Clue, Skip the Dishes
23. mParticle shipping a library generator
24. Covid-related App still in “need to know” status
25. Getting Started
26. https://kotlinlang.org/lp/mobile/
27. github.com/touchlab/KaMPKit
28. Production? seems intro to me…
29. Tooling
30. Intellij the safe choice
31. Android Studio Plugin!
32. Xcode Plugin
33. All use lldb deep in the weeds, but…
35. Crash Reporting CrashKiOS
38. github.com/touchlab/CrashKiOS
39. Package Managers (here be dragons)
40. JS Stuff npm? Typescript?
41. Libraries
42. Check out KaMP KIt mostly what we’re using in prod
43. What’s missing? bad news section
44. 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 }
45. Great Time To Start! still lots of stuff to make
46. Integrating
47. “Selling” KMP/KMM not everybody loves it
48. Start with Empathy “Javascript can do everything!”
49. Find Allies iOS build config is difficult
50. Modifying an iOS any prod build is tough recruit the experts
51. 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”
52. Pick Something Nobody Likes few love core data
53. “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
54. Actually Integrating what I thought this talk would be about
55. Common Android iOS Framework Android Stuff iOS Stuff
56. Greenfield Common Android iOS Framework Android Stuff iOS Stuff
57. Ship Binary Common Android iOS Framework Android Stuff iOS Stuff
58. Kotlin Xcode Plugin intro to Kotlin for iOS devs
59. Why not both? Common Android iOS Framework Android Stuff iOS Stuff
60. Big Topic every team is different
62. Assorted Info and “Bad News”
63. Concurrency it’s different, but changing
64. Two Rules one thread == mutable many threads == immutable (frozen)
65. That is Changing realistically 2nd half of next year
66. Your Code Won’t Change (much) unless you do a lot of concurrency management
67. 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
68. You must learn it or wait till late 2021
69. Kotlinx Coroutines two libraries
70. Ktor and iOS https://medium.com/@kpgalligan/ktor-and-kotlin-native-fb5c06cb920a
71. Simple Answer Kotlin 1.4.* and MT coroutines
72. Single Xcode Framework this is a big one
73. DB KT Framework iOS Stuff Contacts Products Analytics stdlib
74. DB KT Contacts iOS Stuff Contacts Products Analytics stdlib KT Products KT Analytics KT stdlib
75. DB KT Contacts/ Products iOS Stuff Contacts Products Analytics stdlib KT Analytics
76. 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
77. Binary Size generally OK, but complicated
78. Simple Logic 150k DL/500k DI
79. KaMP Kit ~1m DL/~4m DI
80. just kotlin vs swift
82. KT SW
83. KT SW KT-objc
84. KT SW KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc KT KT-objc SW SW SW SW SW SW SW SW SW SW SW SW SW
86. What to do? mark them internal
87. KT SW KT KT KT KT KT KT KT KT KT KT-objc KT KT-objc KT KT-objc SW SW SW SW SW SW SW SW SW SW SW SW SW
88. DB KT Framework iOS Stuff Contacts Products Analytics stdlib
89. DB KT Framework iOS Stuff Contacts Products Analytics stdlib iOS Adapter
90. Size Best Practice a work in progress
91. TL;DR ~1m DL/~4m DI
92. Direct Swift Interop maybe 2021
93. Still Early Apopter-ish alpha in 1.4
94. What’s coming? 2021
95. • 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)
96. Join the Kotlin Slack kotlinlang.org/community/
97. Thanks! @kpgalligan touchlab.co
98. Thanks! @kpgalligan touchlab.co Join the team !