"No services currently exists for key" on restoring History

[edenman]

I'm using Flow with a custom Dispatcher that supports showing multiple keys/screens at the same time (in my case, an underlying screen and modal(s) on top). When my Dispatcher is restoring History from a stopped state, I figure out which keys/screens need to be inflated, and then I call this helper method:

  private fun inflateNewView(screen: Screen, traversal: Traversal): View {
    val context = traversal.createContext(screen, activity)
    val layoutResId = screen.layoutResId()!!
    val inflated = LayoutInflater.from(context).inflate(layoutResId, screenContainer, false)
    inflated.tag = layoutResId
    val incomingState = traversal.getState(screen)
    incomingState.restore(inflated)
    return inflated
  }

However, it looks like PendingTraversal only sets up a context for the top of the History, so when I try to inflate one of the non-top screens, it blows up:

Caused by: java.lang.IllegalStateException: No services currently exists for key StayScreen(placeID=LaTaqueria)
      at flow.KeyManager.findServices(KeyManager.java:72)
      at flow.Traversal.createContext(Traversal.java:44)
      at mypackage.FlowDispatcher.inflateNewView(FlowDispatcher.kt:295)
      at mypackage.FlowDispatcher.doMainScreenTransition(FlowDispatcher.kt:170)
      at mypackage.FlowDispatcher.dispatch(FlowDispatcher.kt:140)
      at flow.Flow$PendingTraversal.bootstrap(Flow.java:364)
      at flow.Flow$2.doExecute(Flow.java:139)
      at flow.Flow$PendingTraversal.execute(Flow.java:381)
      at flow.Flow.move(Flow.java:270)
      at flow.Flow.setDispatcher(Flow.java:137)
      at flow.InternalLifecycleIntegration.onActivityCreated(InternalLifecycleIntegration.java:141)

I think the fix is probably just to pre-create contexts for the entire History, but I don't know if that should be in bootstrap or dispatch. Or am I just doing this custom Dispatcher wrong?

[edenman]

Talked to @loganj offline: the sanctioned way to do this is to use MultiKey. Both KeyManager and KeyDispatcher have custom logic to handle MultiKey and do what i'm currently doing manually.