对长按手势执行多项操作

Question

我正在尝试在长按期间执行某个操作（目前，我只是打印出数据）。但是每当我在 simulator/phone 中做长按手势时，它都会重复这个动作几次。每当激活长按手势时，如何让它只执行一次操作？

抱歉，我是 iOS 开发的新手。

这是我的代码：

@IBAction func addRegion(_ sender: Any) {
    guard let longPress = sender as? UILongPressGestureRecognizer else
    { return }
    let touchLocation = longPress.location(in: mapView)
    let coordinate = mapView.convert(touchLocation, toCoordinateFrom: mapView)
    let region = CLCircularRegion(center: coordinate, radius: 50, identifier: "geofence")
    mapView.removeOverlays(mapView.overlays)
    locationManager.startMonitoring(for: region)
    let circle = MKCircle(center: coordinate, radius: region.radius)
    mapView.add(circle)
    print(coordinate.latitude)
    print(coordinate.longitude)

    //returns:
    // 27.4146234860156
    // 123.172249486142
    // ... (a lot of these)
    // 27.4146234860156
    // 123.172249486142

}

Answer 1

手势识别器函数以其当前状态调用多次。如果您想在长按手势激活时执行某些操作

您应该像下面这样对手势状态应用验证：

       guard let longPress = sender as? UILongPressGestureRecognizer else
        { return }

        if longPress.state == .began { // When gesture activated

        }
        else if longPress.state == .changed { // Calls multiple times with updated gesture value 

        }
        else if longPress.state == .ended { // When gesture end

        }

对长按手势执行多项操作

Multiple actions being performed on Long Press Gesture

ios

swift

uilongpressgesturerecogni