SwiftUI:按下按钮时的动作 [英] SwiftUI: action while pressing a button

问题描述

我正在尝试实现一个长按按钮，该按钮仅在我按下按钮时更改我正在使用的 SF 符号.我也不确定应该在哪里使用图像.问题是当我停止按下时，按钮被触发.有没有办法不激活它(按下时除外)?

I’m trying to implement a long press button that changes the SF Symbol that I’m using only when I’m pressing down on the button. I’m not really sure where I should use the the Images as well. The problem is that when the I stop pressing, the button is triggered. Is there a way to don’t activate it (except while pressing down)?

我正在寻找一个按钮:

当按下 2 秒时，符号改变，2 秒后，当松开时，符号回到<强>初始状态.

When pressed for 2 seconds, the Symbol changes, and after those 2 seconds, when released, the Symbol go back to the initial state.

struct heartButton: View {

@State private var isDetectingPress = false

var body: some View {
    VStack {
        Image(systemName: isDetectingPress ? "heart.fill" : "heart").font(.system(size: 16, weight: .regular))
        Button(action: {
            self.isDetectingPress.toggle()
        }) {
            Text("Button")
        }
    }
}

推荐答案

这里有一个解决方案.使用 Xcode 11.5b 测试.

Here is a solution. Tested with Xcode 11.5b.

struct heartButton: View {

    @GestureState private var isDetectingPress = false

    var body: some View {
        VStack {
            Image(systemName: isDetectingPress ? "heart.fill" : "heart").font(.system(size: 16, weight: .regular))
            Text("Press")
            .gesture(LongPressGesture(minimumDuration: 2).sequenced(before: DragGesture(minimumDistance: 0, coordinateSpace: .local)).updating($isDetectingPress) { value, state, _ in
                    switch value {
                        case .second(true, nil):
                            state = true
                        default:
                            break
                    }
            })
        }
    }
}

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