differences between @Binding and @ObservedObject

In this example, we'll create a simple app with a counter. Tapping a button in the child view will increment the counter, and the updated counter value will be shown in both the parent and child views.

import SwiftUI

struct ContentView: View {
    @State private var counter: Int = 0
    
    var body: some View {
        VStack {
            Text("Counter in Parent: \(counter)")
            ChildView(counter: $counter)
        }
    }
}

struct ChildView: View {
    @Binding var counter: Int
    
    var body: some View {
        Button("Increment Counter") {
            counter += 1
        }
    }
}

In this example, we'll use @ObservedObject to manage the state of a custom data model. The child view will display a person's name from the observed object, and a button will change the name.

import SwiftUI

class Person: ObservableObject {
    @Published var name: String = "John"
}

struct ContentView: View {
    @ObservedObject var person = Person()
    
    var body: some View {
        VStack {
            Text("Person's Name: \(person.name)")
            ChildView(person: person)
        }
    }
}

struct ChildView: View {
    @ObservedObject var person: Person
    
    var body: some View {
        Button("Change Name") {
            person.name = "Alice"
        }
    }
}

 

In this example, the Person class conforms to ObservableObject and uses @Published to automatically notify observers when the name property changes. The ContentView observes changes in the person object using @ObservedObject, and changes to the name made within ChildView are automatically reflected in both views.