UILongPressGestureRecognizer被触发两次

Question

当用户在地图上长按2-4秒时，UILongPressGestureRecognizer会被触发两次。如何确保它只被触发一次？

func action(gestureRecognizer:UIGestureRecognizer) {

    println("long pressed on map")


override func viewDidLoad() {
    super.viewDidLoad()

    manager = CLLocationManager()
    manager.delegate = self
    manager.desiredAccuracy = kCLLocationAccuracyBest

    if activePlace == -1 {

        manager.requestWhenInUseAuthorization()
        manager.startUpdatingLocation()



    } else {

        var uilpgr = UILongPressGestureRecognizer(target: self, action: "action:")
        uilpgr.minimumPressDuration = 2.0
        myMap.addGestureRecognizer(uilpgr)

    }        
}

func action(gestureRecognizer:UIGestureRecognizer) {

    println("long pressed on map")
    var touchPoint = gestureRecognizer.locationInView(self.myMap)
    var newCoordinate = myMap.convertPoint(touchPoint, toCoordinateFromView: self.myMap)

    var annotation = MKPointAnnotation()
    annotation.coordinate = newCoordinate
    //annotation.title = "New Place"
    myMap.addAnnotation(annotation)

    var loc = CLLocation(latitude: newCoordinate.latitude, longitude: newCoordinate.longitude)

}

- user1406716

Answer 1

在开始手势时，您需要检查手势识别器的state：

func action(gestureRecognizer:UIGestureRecognizer) {
    if gestureRecognizer.state == UIGestureRecognizerState.Began {
        // ...
    }
}

- zisoft

Answer 2

长按手势是连续的动作。当指定时间（minimumPressDuration）内按下了允许的手指数量（numberOfTouchesRequired），并且触摸没有移动超出允许的移动范围（allowableMovement），则手势开始(UIGestureRecognizerStateBegan)。每当有一个手指移动时，手势识别器将转换到Change状态。当任何一个手指抬起时，手势结束（UIGestureRecognizerStateEnded）。尝试像这样做：

let longGesture = UILongPressGestureRecognizer(target : self,
 action : #selector(someFunc(gestureRecognizer:)))


func someFunc(gestureRecognizer: UILongPressGestureRecognizer){
if gestureRecognizer.state == .began {
//do something
}

- Sanket Ray