SwiftUI call function on variable change

Question

I am trying to convert a view of my watchOS App to Swift UI. I wanted to port the volume control that can be found in watchKit to SwiftUI with custom controls. In the image

Answer 1

You can use a custom Binding, that calls some code in set. For example from :

extension Binding {
    /// Execute block when value is changed.
    ///
    /// Example:
    ///
    ///     Slider(value: $amount.didSet { print($0) }, in: 0...10)
    func didSet(execute: @escaping (Value) ->Void) -> Binding {
        return Binding(
            get: {
                return self.wrappedValue
            },
            set: {
                self.wrappedValue = $0
                execute($0)
            }
        )
    }
}