SwiftUI SwiftUI State and Data Flow

Question 1

What property wrapper is used to declare local mutable state in a SwiftUI view?

Accepted Answer

@State

Answer

@Binding

Answer

@ObservedObject

Answer

@EnvironmentObject

Question 2

What does `@Binding` do in SwiftUI?

Accepted Answer

Creates a two-way connection to a state owned by another view

Answer

Creates a new state variable

Answer

Observes changes in an ObservableObject

Answer

Reads environment values

Question 3

Which property wrapper connects a view to an external ObservableObject instance?

Accepted Answer

@ObservedObject

Answer

@State

Answer

@Binding

Answer

@Published

Question 4

What protocol must a class conform to in order to be used with `@ObservedObject` or `@StateObject`?

Accepted Answer

ObservableObject

Answer

Identifiable

Answer

Codable

Answer

Equatable

Question 5

When should you use `@StateObject` instead of `@ObservedObject`?

Accepted Answer

When the view owns and creates the object

Answer

When the object is passed from a parent view

Answer

When sharing data across the app

Answer

When the object is a value type

Question 6

What does marking a property with `@Published` inside an ObservableObject do?

Accepted Answer

Automatically notifies subscribers when the property changes

Answer

Makes the property read-only

Answer

Persists the property to UserDefaults

Answer

Marks the property as thread-safe