SwiftUI `@State` and `@Binding`

Concept

• @State declares a view’s own mutable state. When its value changes, the view automatically updates.
• @Binding lets a child view reference and modify a state value that’s owned by a parent view.

Example

struct ParentView: View {
    @State private var isOn: Bool = false
    var body: some View {
        ChildView(isOn: $isOn)
    }
}
 
struct ChildView: View {
    @Binding var isOn: Bool
    var body: some View {
        Toggle("Switch", isOn: $isOn)
    }
}

Sources

• Apple SwiftUI - State
• Apple SwiftUI - Binding