Hi some help needed please. I have one Activity but to keep it tidy I outsourced some of the code to...

# android

[Lilly]

Hi some help needed please. I have one Activity but to keep it tidy I outsourced some of the code to another class called EventHandler. Im working with Kotlin + Dagger 2 (not dagger-android) with currently one simple Component which is built in application class. EventHandler needs the activity or at least some views and I will inject it into my activity so its a circular dependency. Is there a better way to do this or to avoid the circular dependency?

[rook]

If I were you, I would try to remove the activity/view dependency from the EventHandler

[Lilly]

@rook Its difficult to avoid because I will start fragments there:

activity.fragment_navhost.findNavController().navigate(destinationId)

As you can see, I need either the activity or the view. I also handling other events here.

[rook]

You can expose that in an interface to the activity and then just pass the destinationId that way

[Lilly]

sorry can you elaborate your thoughts a bit?

[Lilly]

@rook Actually the EventHandler class implements an NavigationEvent interface and some other events

[Lilly]

@rook ok I guess I know what you mean but that will mess up my activity. Thats the reason why I want to outsource the code

[rook]

I can’t see your code, so I can’t say specifically how to change it to go the direction I’m talking about, but I basically would do something like:

interface NavigableView { fun navigate(navigationKey: String) }
interface MyView : NavigableView

class EventHandler() {
  var currentView: NavigableView? = null

  fun navigate(key: String) { currentView.navigate(key) }
}

class MyActivity() : Activity, MyView {
  override fun navigate(navigationKey: String){
    //navigate somewhere
  }
}

[Lilly]

@rook Its still a circular dependency when I have to set currentView in my activity like:

mEventHandler.currentView = this

My Code looks currently like this:

class MainActivity : BaseActivity(), NavigationEvent {
    override fun startFragment(destinationId: Int) {
        this.fragment_navhost.findNavController().navigate(destinationId)
    }

And I just want to move the NavigationEvent implementation to the EventHandler

[rook]

If you expose it via interface and don’t inject the view, you break the circular dependency

[Lilly]

@rook how can I do that?

[rook]

provide the EventHandler to every view, and at the entry point of every view, have it set the currentView on the EventHandler to itself

override fun onStart() {
  eventHandler.currentView = this
}

[Lilly]

@rook but I don't own the view, its in my case fragment_navhost

[Lilly]

@rook I have a more complete implementation in Java. Are you more familiar with Java or Kotlin?

[rook]

I’m plenty comfortable with either

[Lilly]

ok cool. I will give you an example of my code