Kotlin Multiplatform

The New Cross-Platform Kid in Town

Wajahat Karim

wajahatkarim.com

WajahatKarim

šŸ”„ Google Dev Expert (GDE) in Android .
šŸ“± Android Dev. šŸ’» Open Source Contributor .
Ā  šŸ“ Technical Writer . šŸŽ¤ Public Speaker

2006

2018

Cross-platform

(advantages)

- Faster learning curve

- Smaller team size

- Half of the cost compared to fully native

- Less number of working hours to build

Cross-platform

(disadvantages)

- Tightly dependent on the native framework implementation

- Performance is often affected due to bridging / conversion

- Some native code needs to be written

- New updates from OS will take time to written in cross-platform

Cross-platform

(how it works)

https://wajahatkarim.com/2019/11/how-is-flutter-different-from-native-web-view-and-other-cross-platform-frameworks/

The conversion happens here

kotlin

multiplatform

shares application logic

does not share application UI or native stuff

Cross-platform

(disadvantages)

- Tightly dependent on the native framework implementation

Ā 

- Performance is often affected due to bridging / conversion

Ā 

- Some native code needs to be written

Ā 

- New updates from OS will take time to written in cross-platform

Cross-multiplatform

(disadvantages)

- Tightly dependent on the native framework implementation

Ā 

- Performance is often affected due to bridging / conversion

Ā 

- Some native code needs to be written

Ā 

- New updates from OS will take time to written in cross-platform

Every platform specific thing like for Android / iOS etc is developed natively.

Since its native implementation, so no impact on performance.

Every platform specific thing like for Android / iOS etc is developed natively.

Yes, the UI and other platform-specific code like runtime permissions, hardware APIs etc.

Kotlin Multiplatform

(advantages)

- Kotlin is one of the most trending languages with strong community support

Ā 

- Low risk as you decide what's worth to share across platforms

Ā 

- Consistency across platforms

Ā 

- Supports Android, iOS, Web, Desktop (Mac, Linux, Windows) and more coming.

Android

iOS

Web/Desktop

Android

iOS

Web/Desktop

UI

UI

UI

xml / kotlin

objective-c / swift

html / javascript

Android

iOS

Web/Desktop

UI

UI

UI

presenter / VM

presenter / VM

presenter / VM

model

model

model

parser

parser

parser

network / db

network / db

network / db

business logic

business logic

business logic

xml / kotlin

objective-c / swift

html / javascript

Android

iOS

Web/Desktop

UI

UI

UI

presenter / VM

model

parser

network / db

business logic

common / shared

xml / kotlin

swift / swift UI

javascript / kotlin JS

but how can different platforms can communicate?

https://medium.com/@xxfast/going-fully-multiplatform-1-migrating-your-android-project-to-kotlin-multiplatform-8fc38763307

expect

actual

declared class or method at common/shared module

declared at Android module for Android implementation

declared at iOS module for iOS implementation

declared at js module for Web/Javascript implementation

declared at ...

commonMain

commonMain

Targets: Android, iOS, and Web

- define actual on Android

- define actual on iOS

- define actual on Web

Platform-specific code

Platform-specific code

https://www.cafonsomota.xyz/talks/2020-12-14-droidcon-apac-a-multiplatform-adventure/2020-12-14-droidcon-apac-a-multiplatform-adventure/

Kotlin Multiplatform

(conclusion)

- Strong community

Ā 

- Many big companies are using Kotlin

Ā 

- Jetbrains and Google are pushing Kotlin in

Ā 

- Fantastic support at Slack https://kotlinlang.slack.com

Ā 

- Zero repetition to develop your features business logic

Ā 

- One tech stack for all your targets.

Resources

(articles, links and sample projects)

https://github.com/JetBrains/compose-jb

Ā 

https://github.com/touchlab/KaMPKit

Ā 

https://github.com/joreilly

Ā 

https://kotlinlang.org/lp/mobile/

Ā 

https://kotlinlang.slack.com

Ā 

https://github.com/terrakok/kmm-awesome

Jetpack Desktop Samples

Kotlin Multiplatform Kit

A fantastic GDE working on Kotlin Multiplatform

Official documentation on Kotlin Multiplatform

Slack channel for Kotlin Multiplatform

List of different examples and libraries on Kotlin Multiplatform

Carlos Mota

Codelabs

Special thanks for helping me create these slides

https://cmota.github.io/kmp-codelabs

cafonsomota

Thank You for Listening!

WajahatKarim

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wajahatkarim.com

Kotlin Multiplatform - New Kid in Town

By Wajahat Karim

Kotlin Multiplatform - New Kid in Town

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