Hey guys, I’m trying to migrate RxJava code dealing with Android SharedPreferences to Kotlin Flow. How correct migration should look like?

private val keyChangesObservable: Observable<String>

  init {
    keyChangesObservable = io.reactivex.Observable.create(ObservableOnSubscribe<String> { emitter ->
      val listener = SharedPreferences.OnSharedPreferenceChangeListener { _, key -> emitter.onNext(key) }
      emitter.setCancellable { prefs.unregisterOnSharedPreferenceChangeListener(listener) }
      prefs.registerOnSharedPreferenceChangeListener(listener)
    }).share()
  }

Here you go: https://github.com/LouisCAD/Splitties/blob/c395dcbf9d19fceae67a520215c2ab96fd138390/modules/preferences/src/androidMain/kotlin/splitties/preferences/Changes.kt#L14

Quick Question at Louis, is

runCatching{ offer(event)}

picking up any exception thrown all the way down the Flow stream. Or just catching the operation of offering the event to some EventQueue. What would be the difference of using send(...)?

runCatching in this case would just swallow exception

That’s right but what exception? Any Exception all the way down the stream? It does not look like so. It looks like is just to guard against possible ClosedChannel exceptions but nothing else, is that it?

yes, it’s probably against closedchannel exception

🤔

It should be safe, but I'm not sure and I've been bitten by this throwing unexpectedly in others use cases using Channels in the past, so I'm guarding myself against this bad design until kotlinx.coroutines provides an alternative. I opened an issue for that a while ago: https://github.com/Kotlin/kotlinx.coroutines/issues/974