SOLVED: Updating a Scroll View with a global array

@ben-pomeroy

Nov '20

On my main screen I have a Scroll View which I want to display all of the events that are happening within the app. Currently I have this defined as a global variable as shown below:

struct matchEvent: Identifiable{
    var id = UUID()

    var time: String
    var event: String
    var player: String
}

var matchEvents = [matchEvent]()

func addEvent(time: String, event: String, player: String){
    matchEvents.append(matchEvent(time: time, event: event, player: player))
}

The function addEvent() is called from inside different methods of other classes around the app, hence why I made it global. How do I get the app to update the scroll view when the array matchEvents is updated? I have put my ScrollView code below.

struct eventList: View{
    var body: some View{
        ScrollView(.horizontal){
            HStack(matchEvents){
                ForEach(matchEvents){event in
                    Button(event.event){
                        print("Clicked")
                    }
                }
            }
        }
    }
}

Any help would be appreciated

@delawaremathguy

Nov '20

hi Ben,

i would encapsulate the matchEvents array and the addEvent method in an object (a class) that conforms to the ObservableObject protocol, say something like this

class EventManager: ObservableObject {
  @Published var matchEvents = [matchEvent]()

  func addEvent(time: String, event: String, player: String) {
    matchEvents.append(matchEvent(time: time, event: event, player: player))
  }
}

create a global instance of this class, perhaps var globalEventManager = EventManager(), and then in any View that you want to respond to changes in the array, create a local reference to this variable that is marked with @ObservedObject. so your eventList view would be this:

struct eventList: View{
    @ObservedObject var eventManager = globalEventManager
    var body: some View{
        ScrollView(.horizontal){
            HStack { // <<-- HStack alone here, without the ()?
                ForEach(eventManager.matchEvents){event in
                    Button(event.event){
                        print("Clicked")
                    }
                }
            }
        }
    }
}

i think that's OK. hope that helps,

DMG

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