SwiftUI @StateObject vs @ObservableObject: Memory Management Mastery

Use @StateObject in the view that owns and creates the observable object, and @ObservedObject in child views that receive it as a parameter. This ensures proper ownership and prevents memory issues.

class UserManager: ObservableObject {
    @Published var userName = ""
    @Published var isLoggedIn = false
}

struct ContentView: View {
    @StateObject private var userManager = UserManager()
    
    var body: some View {
        NavigationView {
            VStack {
                UserProfileView(userManager: userManager)
                SettingsView(userManager: userManager)
            }
        }
    }
}

struct UserProfileView: View {
    @ObservedObject var userManager: UserManager
    
    var body: some View {
        TextField("Username", text: $userManager.userName)
    }
}

Why This is a Best Practice

@StateObject creates a strong reference and manages the object's lifecycle, while @ObservedObject assumes the object is managed elsewhere. Mixing these up can cause objects to be deallocated unexpectedly, leading to crashes or data loss during view recreations.

Use @StateObject in the view that owns and creates the observable object, and @ObservedObject in child views that receive it as a parameter. This ensures proper ownership and prevents memory issues.

class UserManager: ObservableObject {
    @Published var userName = ""
    @Published var isLoggedIn = false
}

struct ContentView: View {
    @StateObject private var userManager = UserManager()
    
    var body: some View {
        NavigationView {
            VStack {
                UserProfileView(userManager: userManager)
                SettingsView(userManager: userManager)
            }
        }
    }
}

struct UserProfileView: View {
    @ObservedObject var userManager: UserManager
    
    var body: some View {
        TextField("Username", text: $userManager.userName)
    }
}

Why This is a Best Practice

History

SwiftUI @StateObject vs @ObservableObject: Memory Management Mastery

Why This is a Best Practice