How to create an InstanceKeeper

[manosbatsis]

In our multiplatform's Android module we create an InstanceKeeper singleton for DI (kodein) as follows:

import androidx.lifecycle.ViewModelStore
import com.arkivanov.essenty.instancekeeper.InstanceKeeper
//...

bind<InstanceKeeper>() with singleton { InstanceKeeper(ViewModelStore()) }

My questions are:

1. Is it actually necessary to explicitly create and reuse such an instance?
2. If true, what is the equivalent line for my desktop (jvm) module?

[arkivanov]

It depends on how you use the InstanceKeeper. Typically it is used to survive configuration changes on Android, and yet use it in common code. So the answers are:

1. On Android, it's better to create InstanceKeeper using a ViewModelStore from an Activity or a Fragment. So InstanceKeeper shouldn't be a singleton, it's supposed to be destroyed when the activity/fragment is finished.
2. On other platforms, the InstanceKeeper should be usually scoped to a screen. You can create and pass InstanceKeeperDispatcher there.

[arkivanov]

Also, navigation libraries can manage InstanceKeeper for you. E.g. Decompose automatically provides an instance of InstanceKeeper for every screen.

[manosbatsis]

Thanks, we also use decompose, will do some refactoring to pickup InstanceKeeper from there

[arkivanov]

In this case please check out the doc - https://arkivanov.github.io/Decompose/component/instance-retaining/