SwiftUI on macOS - handle single-click and double-click at the same time - swift

Question

Consider this view in SwiftUI:
struct MyView: View {
var body: some View {
Rectangle()
.fill(Color.blue)
.frame(width: 200, height: 200)
.onTapGesture {
print("single clicked")
}
}
}
Now we're handling single-click. Say you wanna handle double-click too, but with a separate callback.
You have 2 options:
Add double click handler after single click - this doesn't work at all
Add double click handler before single click handler, this kinda works:
struct MyView: View {
var body: some View {
Rectangle()
.fill(Color.blue)
.frame(width: 200, height: 200)
.onTapGesture(count: 2) {
print("double clicked")
}
.onTapGesture {
print("single clicked")
}
}
}
Double-click handler is called properly, but single-click handler is called after a delay of about 250ms.
Any ideas how to resolve this?

Answer 1

Here is possible approach (tested with Xcode 11.2 / macOS 10.15)
struct MyView: View {
var body: some View {
Rectangle()
.fill(Color.blue)
.frame(width: 200, height: 200)
.gesture(TapGesture(count: 2).onEnded {
print("double clicked")
})
.simultaneousGesture(TapGesture().onEnded {
print("single clicked")
})
}
}

Answer 2

The gesture-based solutions don't work correctly when selection is enabled on the List, since the first tap will delay the actual selection. I have made a double click modifier which works on any view and seems to solve it the way I expect in all cases:
extension View {
/// Adds a double click handler this view (macOS only)
///
/// Example
/// ```
/// Text("Hello")
/// .onDoubleClick { print("Double click detected") }
/// ```
/// - Parameters:
/// - handler: Block invoked when a double click is detected
func onDoubleClick(handler: #escaping () -> Void) -> some View {
modifier(DoubleClickHandler(handler: handler))
}
}
struct DoubleClickHandler: ViewModifier {
let handler: () -> Void
func body(content: Content) -> some View {
content.overlay {
DoubleClickListeningViewRepresentable(handler: handler)
}
}
}
struct DoubleClickListeningViewRepresentable: NSViewRepresentable {
let handler: () -> Void
func makeNSView(context: Context) -> DoubleClickListeningView {
DoubleClickListeningView(handler: handler)
}
func updateNSView(_ nsView: DoubleClickListeningView, context: Context) {}
}
class DoubleClickListeningView: NSView {
let handler: () -> Void
init(handler: #escaping () -> Void) {
self.handler = handler
super.init(frame: .zero)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func mouseDown(with event: NSEvent) {
super.mouseDown(with: event)
if event.clickCount == 2 {
handler()
}
}
}
https://gist.github.com/joelekstrom/91dad79ebdba409556dce663d28e8297