Question

当用户长时间按下地图超过2-4秒时，UILongPressGestureRecognizer会被触发两次。我怎样才能确保它只被解雇一次？

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)

}

Answer 1

您必须检查手势识别器的state以获取手势的开头：

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

Answer 2

长按手势是连续的。当指定时间段（minimumPressDuration）按下允许的手指数（numberOfTouchesRequired）并且触摸不超出允许的移动范围（allowableMovement）时，手势开始（UIGestureRecognizerStateBegan）。每当手指移动时，手势识别器都会转换到更改状态，并且当任何手指抬起时，手势识别器会结束（UIGestureRecognizerStateEnded）。

尝试这样的事情：

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


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

UILongPressGestureRecognizer被解雇了两次

2 个答案: