ios - UIPanGestureRecognizer 从不调用 Action 方法

Question

我正在尝试添加 UIPanGestureRecognizer到我的 mapView但我不明白为什么 action 方法永远不会被调用 ( swift 2.1)。

import UIKit
import MapKit

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate, UIGestureRecognizerDelegate
{
    override func viewDidLoad()
    { 
        super.viewDidLoad()

        // other stuff...

        let gestureRecognizer = UIPanGestureRecognizer(target: self, action: "didDragMap:")
        gestureRecognizer.delegate = self
        self.mapView.addGestureRecognizer(gestureRecognizer)
    }

    func didDragMap(sender: UIPanGestureRecognizer)
    {
        // never enter here
    }
}

这里有什么问题？我有相同的 Objective-C 对应，它的工作。

Answer 1

由于 MKMapView 已经处理了它自己的手势，因此您需要启用它来监听您的手势。

实现 shouldRecognizeSimultaneouslyWithGestureRecognizer并像这样返回 true:

func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return true
}

Source