LongPressGesture | Apple Developer Documentation

A gesture that succeeds when the user performs a long press.

https://developer.apple.com/documentation/swiftui/longpressgesture

Handling long-press gestures | Apple Developer Documentation

Detect extended duration taps on the screen, and use them to reveal contextually relevant content.

https://developer.apple.com/documentation/uikit/touches_presses_and_gestures/handling_uikit_gestures/handling_long-press_gestures

1. Base structure

var body: some View {
    VStack {
        Rectangle()
            .fill(.blue)
            .frame(maxHeight: 100)
            .frame(width: 55)
            .frame(maxHeight: .infinity, alignment: .bottom)
            .padding()

        HStack {
            Text("PRESS HERE")
                .padding()
                .glassBackgroundEffect()

            Text("RESET")
                .padding()
                .glassBackgroundEffect()
        }
    }.padding()
}

swift

struct ContentView: View {

    @State private var isComplete: Bool = false
    @State private var isSuccess: Bool = false

    var body: some View {
        VStack {
            progressRectangle
            buttonStack
        }
        .padding()
    }

    private var progressRectangle: some View {
        Rectangle()
            .fill(isSuccess ? Color.green : Color.blue)
            .frame(maxHeight: isComplete ? .infinity : 0)
            .frame(width: 55)
            .frame(maxHeight: .infinity, alignment: .bottom)
            .padding()
    }

    private var buttonStack: some View {
        HStack{
            pressHereButton
            resetButton
        }
    }

    private var pressHereButton: some View {
        Text(isSuccess ? "SUCCESS" : "PRESS HERE")
            .padding()
            .onLongPressGesture(minimumDuration: 3.0, maximumDistance: 50) { isPressing in
                if isPressing {
                    animate {
                        isComplete.toggle()
                    }
                } else {
                    DispatchQueue.main.asyncAfter(deadline: .now() + 0.1){
                        if !isSuccess {
                            animate {
                                isComplete = false
                            }
                        }
                    }
                }
            } perform: {
                animate {
                    isSuccess = true
                }
            }
    }

    private var resetButton: some View {
        Text("RESET")
            .padding()
            .onTapGesture {
                isComplete = false
                isSuccess = false
            }
    }

    private func animate(_ action: @escaping () -> Void) {
        withAnimation(.easeInOut(duration: 3.0), action)
    }
}

swift

onLongPressGesture: This is the core interaction:
- minimumDuration: 3.0 means the press needs to last at least 3 seconds.
- maximumDistance: 50 means the finger can't move more than 50 points during the press.
- Two blocks of code:
  - Start of Press: The isPressing block triggers when the gesture starts and meets the minimum duration:
    - The isComplete variable is toggled (flipped between true and false) using an animation to make the rectangle grow smoothly.
  - End of Press: The second block triggers when the gesture ends. If the action hasn't succeeded (!isSuccess) it resets the isComplete variable after a slight delay (DispatchQueue.main.asyncAfter).
- Gesture Completion (perform:): If the gesture meets all requirements, this block runs and sets isSuccess to true,also with an animation.