I ve been thinking one of the big advantages of Kotlin over

Question

I ve been thinking one of the big advantages of Kotlin over traditional multiplatform frameworks like Xamarin React Native etc seems to be that it isn t a big idea solution that wants you to marry it till death do us part style In theory you could find out that KMP is not for your team or your project and relatively painlessly move to a classical native mobile approach or even something completely different which is not at all the case for those other frameworks So please correct me if I m wrong but on iOS you just have the framework that gets generated and you could keep that but ditch the KMP toolchain entirely and piecewise replace what s in the framework or leave it as it is and use it as a library for as long as it works But what about Android is there a similar route that can be taken or if you want to use what s in the common code do you have to drag KMP along with you forever

Sam · Answer

My android architecture is app gt aar where the aar is a KMP module If I wanted to dump KMP I would just duplicate the source files reconfigure the gradle file and move on iOS would involve rewriting the Kotlin code in Swift which would be a pain in some cases concurrency Thankfully the languages have a very similar feature set

kpgalligan · Answer

On the android side it s all Kotlin which is probably what you d build your android app in anyway I think the issue would be if you d change libraries if you moved away from KMP Like maybe you d switch off ktor The not a big idea solution is definitely a plus for KMP The other thing I like to talk about is the Android side is pretty much what you d do if you were writing an Android app anyway so moving off KMP for Android is way less work than iOS which needs a rewrite in Swift

Andy Gibel · Answer

having just gone the OTHER way and rewritten thousands of lines of Swift for KMP I can confirm it is a PITA lol Gave me a new understanding of all the DISsimilarities of the languages for all people talk about the similarities

kpgalligan · Answer

I don t tell people they re similar anymore They have syntactic similarities but there s a lot of difference

Andy Gibel · Answer

I never knew how robust the matching mechanism in Swift s `switch` statement for instance

matej · Answer

Thanks for the input guys I know KMP is not yet officially touted as primetime ready and there are some squirrelly parts around concurrency but the more I think about it for an app heavy on business logic and a team with limited resources the positives of having a lot of the most important code implemented and tested just once might actually outweigh the moderate to low risks involved The level of lock in in the other frameworks makes me really apprehensive about using them

Andy Gibel · Answer

This was basically my logic I intend to use it for a production library that is pure business logic For all the issues I ve had the end result is worth it IMO

matej · Answer

< Sam> Thanks I think that s exactly what I was thinking So you have a KMP module as a shared library of sorts and for Android you generate an aar out of that same as you generate a framework for iOS It s ready to consume and if for whatever reason you should decide to move away from KMP you could continue using the aar and framework as a library until you were good and ready to move away from it on your own terms Would that be a correct assumption

matej · Answer

< kpgalligan> gt I think the issue would be if you d change libraries if you moved away from KMP Like maybe you d switch off ktor I m imagining a scenario like the high profile exit of Airbnb from React Native where after a while they figured it s not for them After that point they re stuck with RN in some sense forever until they do a full app rewrite It would be the same for Xamarin It s an all or nothing situation whereas in the case or KMP you could draw a line and tell the iOS developers for example from today we re writing all new code natively for each platform You keep your Xcode project for now you continue consuming our KMP framework which we ll replace piecewise as part of our regular maintenance and refactoring effort but with very little up front effort we can basically consider ourselves a regular native mobile dev shop going forward Sure we need to gradually replace parts of the API of our shared business logic KMP library with platform native implementations if that s what we want but we don t have to do it all at once That s a pretty big selling point to bring up to stakeholders in my view

kpgalligan · Answer

That is one of the big reasons we re focused on KMP The interop story is much better than other options which means you can introduce KMP for smaller features to try it out without writing a lot of bridge logic and you can pull it out incrementally if it s not working out I also tell people you have an out if you re releasing soon and there s something you don t like in the shared code It s pretty easy to just code that part native

kpgalligan · Answer

I don t have a video but slides from an intro talk about KMP I did recently The intro is about why it s different than other options <https speakerdeck com kpgalligan kotlin multiplatform intro slide=21>

kpgalligan · Answer

Oh no there is a video <https vimeo com 371428809>

Andy Gibel · Answer

great into talk < kpgalligan> Is it OK if I borrow some of those slides for an internal talk I basically have your job but at a smaller scale slightly smiling face

kpgalligan · Answer

Sure If you need originals I can send a keynote file

Dmitri Sh · Answer

Same here < kpgalligan> can I borrow Doing a code week project presenting KMP this would really help

Andy Gibel · Answer

Keynote would be amazing Thanks

kpgalligan · Answer

KMP Intro Keynote

Dmitri Sh · Answer

thanks

matej · Answer

< kpgalligan> Wow thank you so much for sharing this it s going to be incredibly useful for internal discussions

mkojadinovic · Answer

Thanks for sharing this < kpgalligan> bow