Just finished a new POC with Orbit on KMM grounds....

# orbit-mvi

[Guilherme Delgado]

Just finished a new POC with Orbit on KMM grounds. Not yet ready to make it public (SwiftUI time), but I can share a quick feedback about KMM/Android: ❤️ - there you go.
A quick question: I know there’s no SavedStateHandle logic in KMM, but how one can save state when sharing ViewModels? 🤔 Is it even possible?

[appmattus]

really the best is to cache data at a different layer, for example in a database backed by sqldelight or for small amounts of data you could use multiplatform-settings

[appmattus]

i did originally play with multiplatform saved state but to be honest the way state saving works on iOS didn't sit well with me - i was looking at it from a process death point of view but the lifecycle of the data is longer than that of SavedStateHandle

[Guilherme Delgado]

do you have any sample I could look into?

[Guilherme Delgado]

what I like about SavedStateHandle is the “auto setup/restore” it offers, I was thinking trying using multiplatform-settings, but that means I have to manually save the state every reduce operation 🤔 makes sense? Then in the container init I check if I have something cached, on override fun onCleared() I call .clear()
problems:
• saving in cache upon any reduce may not be optimal
• how do i clear this cache when user kills the app manually, in other words, how can I distinguish between system kill or user kill (the latter I want a cache cleared)? 🤔

[miqbaldc]

https://github.com/orbit-mvi/orbit-sample-posts-multiplatform cmiiw, this should be the sample for KMM using orbit-mvi

[Guilherme Delgado]

yup but that sample doesn’t have state restore logic, or am I wrong?

[Guilherme Delgado]

@appmattus actually theres a way to solve problem 2

how do i clear this cache when user kills the app manually, in other words, how can I distinguish between system kill or user kill (the latter I want a cache cleared)?

a very very 🔨 time one 😅 , clearing cache if splash launches 😬

<intent-filter>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

it works but i don’t like it very much…

[appmattus]

and then comes the problem of the functionality working the same on iOS 🤣🤣🤣

[Guilherme Delgado]

ahah yeah, god damn it

[appmattus]

The way the state saving works at the moment is every change is sent through the savedstatehandle but I believe that manages persistence in a sane way for you

[Guilherme Delgado]

yup i actually like the way orbit handles this (without VM shared)

[appmattus]

No not really and no sample to look at either. I was mainly messing around in pure swift code to understand how things worked there rather than having anything usable - this was before the swift generation plugin existed though so I was struggling to see how I'd get anything into Multiplatform code

[Guilherme Delgado]

do you think we could have a shared VM with the “core” logic, let’s say, and then on each plat. we extend that VM to implement state restore?

[Guilherme Delgado]

I was imagining the VM also observing the state flow

[Guilherme Delgado]

dunno 🤔

[appmattus]

In theory yes, my concern is the amount of boilerplate someone would have to write…

What we had thought about was a platform independent wrapper around savedstatehandle that you'd have to provide to the container.

I'm sure the problem is solvable so really it's a problem of time. I wanted to better publish what we do have working for KMM first before tackling this problem or we won't get anything out of the door.

[Guilherme Delgado]

Yup that sounds a good idea

[appmattus]

It's hacktoberfest so rather selfishly I've been spending time on some of my other open source projects otherwise they get no love

[Guilherme Delgado]

yes I totally get you 😉

[Guilherme Delgado]

I’m very happy with the state of orbit, thanks for your work guys

[miqbaldc]

do you think we could have a shared VM with the “core” logic, let’s say, and then on each plat.

afaik https://danielebaroncelli.medium.com/ shares a lot related to use a shared VM

[Guilherme Delgado]

Thanks for your input @miqbaldc, that articles series are very good

[Guilherme Delgado]

in its example: https://github.com/dbaroncelli/D-KMP-sample/blob/main/shared/src/commonMain/kotlin/eu/baroncelli/dkmpsample/shared/viewmodel/StateManager.kt
I could be wrong, but I get the feeling this class tries to implement an MVI logic

[Guilherme Delgado]

I did not found state restore, maybe I’ve missed it.

[appmattus]

yes, in Daniele's articles he talks about MVI being the natural architecture for KMM although he's gone a lot further in modelling the navigation as part of the app state whereas in Orbit we leave that to the platform - as far as i can tell there is no attempt to store the state for restoration