How to detect a tap gesture location in SwiftUI?

Question

(For SwiftUI, not vanilla UIKit) Very simple example code to, say, display red boxes on a gray background:

struct ContentView : View {     @State var points:[CGPoint] = [CGPoint(x:0,y:0), CGPoint(x:50,y:50)]     var body: some View {         return ZStack {             Color.gray                 .tapAction {                    // TODO: add an entry to self.points of the location of the tap                 }             ForEach(self.points.identified(by: \.debugDescription)) {                 point in                 Color.red                     .frame(width:50, height:50, alignment: .center)                     .offset(CGSize(width: point.x, height: point.y))             }         }     } } 

I'm assuming instead of tapAction, I need to have a TapGesture or something? But even there I don't see any way to get information on the location of the tap. How would I go about this?

Answer 1

Well, after some tinkering around and thanks to this answer to a different question of mine, I've figured out a way to do it using a UIViewRepresentable (but by all means, let me know if there's an easier way!) This code works for me!

struct ContentView : View {     @State var points:[CGPoint] = [CGPoint(x:0,y:0), CGPoint(x:50,y:50)]     var body: some View {         return ZStack(alignment: .topLeading) {             Background {                    // tappedCallback                    location in                     self.points.append(location)                 }                 .background(Color.white)             ForEach(self.points.identified(by: \.debugDescription)) {                 point in                 Color.red                     .frame(width:50, height:50, alignment: .center)                     .offset(CGSize(width: point.x, height: point.y))             }         }     } }  struct Background:UIViewRepresentable {     var tappedCallback: ((CGPoint) -> Void)      func makeUIView(context: UIViewRepresentableContext<Background>) -> UIView {         let v = UIView(frame: .zero)         let gesture = UITapGestureRecognizer(target: context.coordinator,                                              action: #selector(Coordinator.tapped))         v.addGestureRecognizer(gesture)         return v     }      class Coordinator: NSObject {         var tappedCallback: ((CGPoint) -> Void)         init(tappedCallback: @escaping ((CGPoint) -> Void)) {             self.tappedCallback = tappedCallback         }         @objc func tapped(gesture:UITapGestureRecognizer) {             let point = gesture.location(in: gesture.view)             self.tappedCallback(point)         }     }      func makeCoordinator() -> Background.Coordinator {         return Coordinator(tappedCallback:self.tappedCallback)     }      func updateUIView(_ uiView: UIView,                        context: UIViewRepresentableContext<Background>) {     }  }