Challenges in Kotlin Multiplatform Mobile for Mobile Developer

KMM is the future of mobile apps and hopefully, a replacement for flutter/react native apps. As being an advantage of code reusability, kotlin plays a pivotal role that KMM also took this benefit by writing kotlin shared code that would work as a single codebase in building awesome iOS and Android apps. As an Android dev, you would face a few challenges while writing KMM app because of having a shared codebase between iOS and Android app and developers also have to use those items that would be supported in both OS.

So in this talk, I have discussed restrictions, limitations, and challenges we have to keep in mind while writing KMM apps, and as the kotlin syntax is also much similar to iOS syntax that it would also help iOS dev to work on KMM apps.

Transcript

1. Challenges in Kotlin Multiplatform Mobile Discuss challenges that would face by an android dev when building an iOS/Android App. Mostly Photo in this slide are by Unknown Author is licensed under CC BY-NC
2. ALI AZAZ ALAM SR. Android Application developer @VeeOne Health @aliazaz @aliazazalam1 @ali.azaz.alam
3. Background of Mobile Applications
4. Android App Development platforms • Traditionally, Android app development would be done through native languages like Java | Kotlin and UI through XML & Jetpack Compose. • Even though, there are also other ways to achieve an app using cost effective and awesome UI.
5. iOS App Development platforms • iOS application development is a little bit restrictive due to its IDE i.e Xcode. • iOS Apps written traditionally in Objective-C and now dev adopts SwiftUI. • Swift awesome UI and backward code support through Objective-C.
6. Hybrid Applications platforms
7. KMM vs KMP KMM – Deals with mobile platform. KMP - Deals for all platform, including iOS, Android, and Web
8. KMM •Create cross platform app with native code. •Adopted by world’s leading companies, including Philips, Netflix, Leroy Merlin, and VMWare. •Single codebase for the application logic. •In alpha right now
9. CocoaPods Dependency • CocoaPods is a dependency manager for Swift and Objective-C Cocoa projects. • It has over 90 thousand libraries and is used in over 3 million apps. • CocoaPods can help you scale your projects elegantly.
10. Understanding KMM project Structure
11. Contd.. Url: https://tinyurl.com/kmmprojectstructure
12. Actual / Expect – under the hood •Implementation that all OS would do it by themselves. •It is like a lateint modifier, means promise that I would do expect implementation at all OS side. • Expect is like an interface in Kotlin and protocol in Swift.
13. Contd. Shared folder: CommonMain Shared folder: AndroidMain Shared folder: iOSMain
14. Challenges/Limitations while working in KMM and their resolutions.
15. Ktor - Network •In android - use Retrofit/Volley for network calls. •In iOS – use AlamoFire/AFNetworking for network calls. •Because these Api’s are not available in KMM we have to target Ktor for it. •Kotlin Serialization – works with Ktor.
16. Get | Post Request and receiving Shared folder: CommonMain Android folder: MainActivity
17. Ktor – Challenge for iOS •Coroutine is bundled with Ktor to do asynchronous calls. •With coroutine run the app on Main | IO thread. •iOS doesn’t any concept of coroutine or suspend function. •Use callback to deal with coroutine.
18. Receiving request - iOS iOS project: Xcode / ContentView.swift
19. Contd. Url: https://tinyurl.com/kotliniosmapping
20. Contd. Shared folder: CommonMain Shared folder: AndroidMain Shared folder: iOSMain Darwin: iOS, macOS, watchOS, tvOS
21. Contd. Logging network calls Logging code is same that’s why put it on both iOS and android side.
22. Storage •Local Caching is also required when dealing with app that requires data to store for future use, like token, login info, and so on. •In Android – Use Room and In iOS – Core Data, but no one is available in KMM, therefore here is SqlDelight. •There is one storage Api that is now available in KMM i.e Realm.
23. SQL-Delight •Type safe •Work with SQLite, MySql, and PostGresSQL. •It work as a glue between database scheme that you defined and platform specific need.
24. Contd.
25. Contd. ./shared/CommonMain Call Database Helper class.
26. Challenges in defining ViewModel in Shared/CommonMain Shared folder: CommonMain Shared folder: AndroidMain Shared folder: iOSMain
27. ViewModel – CommonMain Implementation
28. ViewModel – Calling at Android side Android folder: MainActivity
29. ViewModel – Calling at iOS side iOS Project: Xcode / Collector.swift
30. Contd. iOS Project: Xcode / LanguageVM.swift
31. Dependency Injection •One object supplies the dependencies of another object. •In Android – Dagger & Hilt and in iOS – Swinject & Manual. •In KMM these of them aren’t available but we have Koin that is compatible with KMP.
32. Koin •A lightweight dependency injection framework. •Declarative library, DSL. •Use modules for declare dependencies. •Use single{..}, singleOf{..} & factory{..}, factoryOf{..}
33. ./Shared/C ommonMa in – Koin.kt Contd.
34. ./Shared/CommonMain – GeneralRepository.kt ---- Inject dependencies AndroidProject/MainApp.kt ---- Initializing Koin Contd.
35. Retrieve dependencies in iOS through Koin.
36. Retrieve dependencies at iOS side.
37. Working App
38. Best Opensource Libraries for KMM
39. Logging Napier logging ./Shared/AndroidMain & iOS Main – Initialization Calling: Kermit logging No initialization required - Implementation Calling:
40. Moko-Resources •KMM library to share resources between both OS. •Resources includes Strings, Plurals, Images, Fonts, Colors, and Files.
41. Contd. AndroidProject / res/MainActivity.xml ./Shared/CommonMain StringLocalization.kt ./Shared/iOSMain StringLocalization.kt
42. Working example:
43. Moko-MVVM • ViewModel - store and manage UI-related data. Interop with Android Architecture Components - on Android it's precisely androidx.lifecycle.ViewModel; • LiveData, MutableLiveData, MediatorLiveData - lifecycle-aware reactive data holders • EventsDispatcher - dispatch events from ViewModel to View with automatic lifecycle control and explicit interface of required events; • DataBinding, ViewBinding, Jetpack Compose, SwiftUI support - integrate to Android & iOS app with commonly used tools; • All Kotlin targets support - core, flow and livedata modules support all Kotlin targets.
44. Best Available Resources for learning KMM
45. Video of this Talk https://tinyurl.com/aliazazgeeklekmm
46. References • Kotlin multiplatform by tutorials by the raywenderlich tutorial team Kevin D.Moore, Carlos Mota & Saeed Taheri • https://github.com/icerockdev • https://github.com/AAkira/Kotlin-Multiplatform-Libraries • https://student.cs.uwaterloo.ca/~cs398/1-syllabus/2-weekly-schedule/lectures/13-kotlin-multiplatform-slides.pdf • https://mmmnnnmmm.com/kotlin-kmm-swift-ios-stateflow.html • https://kotlinlang.org/docs/native-objc-interop.html#mappings • https://ktor.io/docs/getting-started-ktor-client-multiplatform-mobile.html
47. Thanks a lot for attending this session