Checking state during action execution

[Otacon]

The state of the UIDataStore should be checked right before running the Action and not when trying to enqueue it.
Let's make a simple test:

Activity

class Activity: Activity{ 
    onCreate() { viewModel.onCreate() }
    onStart() { viewModel.onStart() }
    onResume() { viewModel.onResume() }
    ...
}

ViewModel

class MyViewModel: AndroidDataFlow(){
    ...
    fun onCreate() = actionOn<UIState.Empty>{ setState { MyState.Created } }
    fun onStart() = actionOn<MyState.Created>{ setState { MyState.Started } }
    fun onResume() = actionOn<MyState.Started>{ setState { MyState.Resumed } }
    ...
}

When onCreate is called, the actionOn will be enqueued successfully.
Now onStart will be called, but still the first action hasn't been executed yet, so the current state is still UIState.Empty. This will cause the submission of the onStart action to fail with BadOrWrongState event.

With this fix, the order of the actions will be preserved, since the check is done while running the action.

[Otacon]

Not sure if this is the correct way of sending a UIEvent.BadOrWrongState internally

[arnaudgiuliani]

yeah, perhaps we can register the state class when we make an action. In case of simple action, no need of particular class. In actionOn case, we need it

[erikhuizinga]

I'm sorry, I have no time to review this PR this or next week.

[arnaudgiuliani]

I'm sorry, I have no time to review this PR this or next week.

no worry, sorry for disturbing 👍

[arnaudgiuliani]

I'm closing this PR as I've made a fix in new engine. Let's keep in touch.