ObservableObject, @ObservedObject and @published

ObservedObject.swift

import SwiftUI

class Counter: ObservableObject {  
  @Published var count: Int
  
  init(_ count: Int) {
    self.count = count
  }
  
  func increment() {
    count = count + 1
  }
}


struct ContentView: View { 
    @ObservedObject var counter = Counter(0)
  
    var body: some View {
      VStack {
        Text(String(counter.count))
        Button("+ 1", action: { counter.increment() })
      }.font(.system(size: 26))
    }
}