A Multiplatform Adventure

Kotlin Multiplatform is here to stay! We start to see several products in production that are already migrating part of their code/ implementing new features with KMP. The goal here is simple, develop your application logic once and use it on every platform.

So join me on the next two hours on this multiplatform adventure and let’s create an app for android and iOS.

Transcript

1. A Multiplatform Adventure workshop edition @cafonsomota
2. Android Dev Lead @WITSoftware Founder @GDGCoimbra and co-founder @Kotlin_Knights ✍ Author @rwenderlich and @opinioesonline Podcaster wannabe Loves travel, photography and running @cafonsomota
3. MATERIALS speakerdeck.com/cmota/a-multiplatform-adventure github.com/cmota/kmm-a-multiplatform-adventure cmota.github.io/kmp-codelabs IDE’s required Android Studio Xcode @cafonsomota
4. @cafonsomota install KMM plugin on Android Studio
5. $ git clone https:!//github.com/cmota/kmm-all-together-now.git install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now
6. $ git clone https:!//github.com/cmota/kmm-all-together-now.git AllTogetherNow [kmm-all-together-now/00. Starter Project] install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now open “00. Starter Project”
7. $ git clone https:!//github.com/cmota/kmm-all-together-now.git AllTogetherNow [kmm-all-together-now/00. Starter Project] install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now open “00. Starter Project” wait for gradle to finish
8. xkcd.com/303/
9. > Task :shared:cinteropFirebaseFirestoreIos FAILED 2 actionable tasks: 1 executed, 1 up-to-date xcrun: error: unable to find utility "xcodebuild", not a developer tool or in PATH Exception in thread "main" org.jetbrains.kotlin.konan.MissingXcodeException: An error occurred during an xcrun execution. Make sure that Xcode and its command line tools are properly installed. at org.jetbrains.kotlin.konan.target.CurrentXcode.xcrun(Xcode.kt:77) at org.jetbrains.kotlin.konan.target.CurrentXcode.access$xcrun(Xcode.kt:45) at org.jetbrains.kotlin.konan.target.CurrentXcode$version$2.invoke(Xcode.kt:70) at org.jetbrains.kotlin.konan.target.CurrentXcode$version$2.invoke(Xcode.kt:45) at kotlin.SynchronizedLazyImpl.getValue(LazyJVM.kt:74) AllTogetherNow [kmm-all-together-now/00. Starter Project] install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now open “00. Starter Project” wait for gradle to finish ❌ no Xcode installed
10. !/* If you don't have Xcode installed comment this code block!*/ !/* Search for this comment on build.gradle.kts (:shared) and comment all the references to iOS: * - onPhone * - cocoa pods * - iosMain * - iosTest * - packForXcode * - tasks.getByName(“build”) !*/ AllTogetherNow [kmm-all-together-now/00. Starter Project] install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now open “00. Starter Project” wait for gradle to finish comment iOS related blocks on build.gradle.kts (:shared)
11. BUILD SUCCESSFUL in 11s 44 actionable tasks: 44 executed AllTogetherNow [kmm-all-together-now/00. Starter Project] install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now open “00. Starter Project” wait for gradle to finish ✅ Xcode installed
12. iosApp: pod install install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now open “00. Starter Project” wait for gradle to finish go to iosApp folder on Terminal and execute “pod install”
13. install KMM plugin on Android Studio github.com/cmota/kmm-all-together-now open “00. Starter Project” wait for gradle to finish go to iosApp folder on Terminal and execute “pod install” compile and run the app $ git clone https:!//github.com/cmota/kmm-all-together-now.git AllTogetherNow [kmm-all-together-now/00. Starter Project]
14. @cafonsomota and now we wait… (In KMM defense, well we’ve got the FirebaseFirestore lib as a pod)
15. dev-reactions/crash-in-production.gif
16. A Multiplatform Adventure A bit of theory… @cafonsomota
17. @cafonsomota dev-reactions/commitstrip/unrealist-mobile-dev-dream
18. 2008 2012 2018 2013 2011 2017 2006 2010 2009 2015 * Kotlin Multiplatform *
19. - Smaller team - Small learning curve for web developers - Typically half of the cost needed on native - Less time (working hours) to built (advantages) Cross-platform to test to fix issues (hopefully not framework specific )
20. - Chained to the framework implementation of UI - new updates from the OS will take time to adopt - Performance is not the same - Some native code might need to be written - OS/ device features are dependent on the fw support - Dart (flutter) is not widely used language (for now) - Committed to one framework/ language (disadvantages) Cross-platform
21. what about Kotlin Multiplatform?
22. shares application logic doesn’t share the application UI kotlin multiplatform
23. - Chained to the framework implementation of UI - new updates from the OS will take time to adopt - Performance is not the same - Some native code might need to be written - OS/ device features are dependent on the fw support - Dart (flutter) is not widely used language (for now) - Committed to one framework/ language (disadvantages) Cross-platform
24. - Chained to the framework implementation of UI - new updates from the OS will take time to adopt - Performance is not the same - Some native code might need to be written - OS/ device features are dependent on the fw support - Dart (flutter) is not widely used language (for now) - Committed to one framework/ language Cross-multiplatform UI is developed natively nope, as fast as an update to the SDK and recompile the apps
25. - Chained to the framework implementation of UI - new updates from the OS will take time to adopt - Performance is not the same - Some native code might need to be written - OS/ device features are dependent on the fw support - Dart (flutter) is not widely used language (for now) - Committed to one framework/ language Cross-multiplatform nope, as fast as an update to the SDK and recompile the apps UI is developed natively always arguable, but you’re leaving UI to native, so…
26. - Chained to the framework implementation of UI - new updates from the OS will take time to adopt - Performance is not the same - Some native code might need to be written - OS/ device features are dependent on the fw support - Dart (flutter) is not widely used language (for now) - Committed to one framework/ language Cross-multiplatform nope, as fast as an update to the SDK and recompile the apps yes, the UI UI is developed natively always arguable, but you’re leaving UI to native, so…
27. - Chained to the framework implementation of UI - new updates from the OS will take time to adopt - Performance is not the same - Some native code might need to be written - OS/ device features are dependent on the fw support - Dart (flutter) is not widely used language (for now) - Committed to one framework/ language Cross-multiplatform nope, as fast as an update to the SDK and recompile the apps yes, the UI UI is developed natively you have direct access to them; although if on shared module it might give you extra effort always arguable, but you’re leaving UI to native, so…
28. - Chained to the framework implementation of UI - new updates from the OS will take time to adopt - Performance is not the same - Some native code might need to be written - OS/ device features are dependent on the fw support - Dart (flutter) is not widely used language (for now) - Committed to one framework/ language Cross-multiplatform nope, as fast as an update to the SDK and recompile the apps yes, the UI UI is developed natively kotlin, is one of the most trending languages nowadays, with strong community support always arguable, but you’re leaving UI to native, so… you have direct access to them; although if on shared module it might give you extra effort
29. (advantages) - Language features - Kotlin first! - Low risk - You decide what’s worth to share across platforms - Interoperability - Consistency across platforms - Strong investment from JetBrains and community support Kotlin Multiplatform server web native android desktop jvmMain jsMain androidMain iosMain macosX64Main linuxX64Main mingwX64Main
30. - It’s in alpha - Although we keep seeing new projects in production - Space was announced during Kotlin Conf 19 (web, desktop and mobile) (apps in production) Kotlin Multiplatform Space Adapted from: KotlinConf 2019: Opening Keynote by Andrey Breslav Full KMP Cash App Shares: business logic Yandex Maps Shares: business logic, wrappers for C++ libraries PlanGrid Planboard Workspace Shares: business logic, sync logic, mgmnt offline data Shares: business logic, networking, offline caching lyrs Shares: business logic
31. - Open source - Concise, safe, interoperable, tool-friendly - Supported/ used by Google for Android Development - It’s more than “just for Android” - Small learning curve involved - Easily to go from JavaScript/ Swift into Kotlin and back Kotlin
32. var variable = 42 variable = 1 let value = 42 var variable = 42 variable = 1 val value = 42 *adapted from http://nilhcem.com/swift-is-like-kotlin/ (variables and constants) Kotlin vs Swift Kotlin Swift
33. fun greet(name: String, day: String): String { return "Hello $name, today is $day." } greet(“World”, “Thursday”) *updated from http://nilhcem.com/swift-is-like-kotlin/ func greet(_ name: String,_ day: String) -> String { return "Hello \(name), today is \(day)." } greet(“World”, “Thursday”) Kotlin Swift (functions) Kotlin vs Swift
34. K otlin multiplatform using kotlin in projects that target more than one platform
35. network network network parser parser parser model model model presentation presentation presentation model parser network view presentation view view view presentation presentation presentation desktop web iOS android
36. business logic business logic business logic model parser network presentation model parser network presentation model parser network presentation model parser network presentation business logic view view view view desktop web iOS android
37. android iOS web desktop model parser network presentation common view view view view java/kotlin objective-c/ swift (kotlin) JS supported in jvm
38. dev-reactions/it-works.gif
39. but how can different platforms expect to communicate?
40. declared at common module expect declared at android module actual declared at iOS module declared at …
41. we want a platform-specific value for the device name
45. dev-reactions/god-mode.gif
48. - User interface - RecyclerView and more (Android) - UITableViewController and more (iOS) - Multiple network request - Parse response objects - Store on local database - Use system preferences - Migrate code to Multiplatform Project structure
49. android iOS Room CoreData Retrofit Alamofire GSON/ Moshi JSONSerialization MVP, MVVM, MVI MVVM, ELM RxJava RxSwift Tests Tests Activity UIViewController RecyclerView UITableView
50. Room CoreData Retrofit Alamofire GSON/ Moshi JSONSerialization MVP, MVVM, MVI MVVM, ELM RxJava RxSwift Tests Tests Activity UIViewController RecyclerView UITableView android iOS
51. Room CoreData Retrofit Alamofire GSON/ Moshi JSONSerialization MVP, MVVM, MVI MVVM, ELM RxJava RxSwift Tests Tests Activity UIViewController RecyclerView UITableView android iOS Activity UIViewController RecyclerView UITableView unnecessary duplication
52. SQLDelight ktor kotlinx.serialization MVP kotlinx.coroutines kotlin.test android iOS Activity UIViewController RecyclerView UITableView
53. multiplatform ktor SQLDelight model kotlinx.serialization SendMessages GetConferences SQLDriver dispatcher view presenter Settings Firebase presenter
54. @cafonsomota cmota.github.io/kmp-codelabs/ cmota.github.io/kmp-codelabs
55. @cafonsomota > Configure project :shared Kotlin Multiplatform Projects are an Alpha feature. cmota.github.io/kmp-codelabs
56. speakerdeck.com/cmota/a-multiplatform-adventure github.com/cmota/kmm-a-multiplatform-adventure cmota.github.io/kmp-codelabs @cafonsomota