22.1 State Properties

The most basic form of state is the state property. State properties are used exclusively to store state that is local to a view layout such as whether a toggle button is enabled, the text being entered into a text field or the current selection in a Picker view. State properties are used for storing simple data types such as a String or an Int value and are declared using the @State property wrapper, for example:

struct ContentView: View {

 

    @State private var wifiEnabled = true

    @State private var userName = ""

 

    var body: some View {

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Note that since state values are local to the enclosing view they should be declared as private properties.

Every change to a state property value is a signal to SwiftUI that the view hierarchy within which the property is declared needs to be re-rendered. This involves rapidly recreating and displaying all...