iOS 14.0+
You can use the onChange(of:perform:)
modifier, like so:
struct ContentView: View {
@State private var isLightOn = false
var body: some View {
Toggle("Light", isOn: $isLightOn)
.onChange(of: isLightOn) { value in
if value {
print("Light is now on!")
} else {
print("Light is now off.")
}
}
}
}
iOS 13.0+
The following as an extension of Binding
, so you can execute a closure whenever the value changes.
extension Binding {
/// When the `Binding`'s `wrappedValue` changes, the given closure is executed.
/// - Parameter closure: Chunk of code to execute whenever the value changes.
/// - Returns: New `Binding`.
func onUpdate(_ closure: @escaping () -> Void) -> Binding<Value> {
Binding(get: {
wrappedValue
}, set: { newValue in
wrappedValue = newValue
closure()
})
}
}
Used like so for example:
struct ContentView: View {
@State private var isLightOn = false
var body: some View {
Toggle("Light", isOn: $isLightOn.onUpdate(printInfo))
}
private func printInfo() {
if isLightOn {
print("Light is now on!")
} else {
print("Light is now off.")
}
}
}
This example doesn’t need to use a separate function. You only need a closure.