Kotlinx.serialization: How can I use kotlinx.serialization instead on Android Parcelable in cross-platform projects?

[alexandr2levin]

I realised that Kotlin's @Parcelize annotation won't work for me as part of my class that need to be Parcelable stored in non-android modules.

   - common (contains classes that needs to be Parcelable)
   - desktop-editor
   - android-app

I think that I can annotate classes in common module and then serialize them to byte[] in android-app module to store them inside Bundle just like Parcelable do.

So, how can I manage this?

[pdvrieze]

You can use the protobuf format to do this. As an alternative you could use the multiplatform support to handle the differences with a common codebase.

[sandwwraith]

You can also use CBOR. It can be more convenient, since you don't need to mark up your class with @SerialId.

However, it's a good idea for FR to provide @Serializable - based implementation of Parcelable to be able to save on Android serializable classes from common code.

[JakeWharton]

Are you serializing in the desktop module? If not, you should be able to just create a dummy annotation in common and typealias it to Parcelize in the android module.

[sandwwraith]

Parcelize plugin requires making class implements Parcelable by hand, as far as I remember

[JakeWharton]

Sure, but that interface can also be typealiased back to the real thing and made empty in the desktop module.

[alexandr2levin]

@JakeWharton on desktop I serialize data as json. Nice Idea btw, but I will try to use CBOR

[thebehera]

Wouldn't using CBOR/JSON/protobuf (assuming there is a library involved) format incur more memory/CPU at runtime as well as boilerplate compared to using @Parcelize that generates the code at build time?

Also I'm kind of curious, how would we also annotate the same model with @Entity to ensure we can use it in a Room database? That way we can define a single model that can be used between several platforms and we wont have to include boilerplate to convert between models (pojo to json/protobuf/CBOR/SQL)

[thebehera]

@JakeWharton do you have an example of that anywhere?

[JakeWharton]

No, but just do the same thing I outlined above with typealiases

[JakeWharton]

Partial actual-ing of common expect annotations just shipped in 1.2.60-eap-44 (aka RC) meaning you no longer need to actual platform-specific annotations on platforms for which they don't make sense which makes this slightly easier.

[dzastinas]

So how can i use kotlinx serialized data class in android-app module to store data inside the Bundle?

[pdvrieze]

@dzastinas You would need to write a format that writes the data to a parcel (probably not to a bundle). I'm not aware of one already existing, but it isn't too hard.

[AhmedMourad0]

@dzastinas I've just published a lib that does just that: https://github.com/AhmedMourad0/bundlizer

[AhmedMourad0]

@pdvrieze Can you elaborate please, why not a Bundle?