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State & Binding

June 02, 2026 • 1 min read

SwiftUI redraws when state changes. @State holds a view's private data; @Binding lets a child view read and write a parent's state.

@State

struct CounterView: View {
    @State private var count = 0
    var body: some View {
        Button("Count: \(count)") { count += 1 }
    }
}

@Binding

struct ToggleRow: View {
    @Binding var isOn: Bool
    var body: some View { Toggle("Enabled", isOn: $isOn) }
}
// parent passes $someState to it

The \$ prefix creates a binding to a state value.

Common mistake: @State is for simple, view-local data. For shared/complex data use ObservableObject (next topics).

Summary

@State drives a view's own UI; @Binding shares mutable state with child views via the \$ prefix.