这个问题的解决方案是允许同时的手势。只需设置长按手势的delegate并实现以下delegate方法：

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

就是这样。Map视图上的长按手势现在每次都有效。
作为演示，创建一个基于Swift和故事板的新iOS项目。将提供的ViewController.swift实现替换为以下内容：

import UIKit
import MapKit

class ViewController: UIViewController {
    let mapView = MKMapView()

    override func viewDidLoad() {
        super.viewDidLoad()

        mapView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(mapView)

        NSLayoutConstraint.activate([
            mapView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            mapView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            mapView.topAnchor.constraint(equalTo: view.topAnchor),
            mapView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
        ])

        let lp = UILongPressGestureRecognizer(target: self, action: #selector(longPress))
        lp.delegate = self
        view.addGestureRecognizer(lp)
    }

    @objc func longPress(_ gesture: UILongPressGestureRecognizer) {
        switch gesture.state {
            case .began:
                print("began")
            case .ended:
                print("ended")
            case .changed:
                print("changed")
            case .cancelled:
                print("cancelled")
            default:
                print("other")
        }
    }
}

extension ViewController: UIGestureRecognizerDelegate {
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
}

请注意，shouldRecognizeSimultaneouslyWith会被调用很多次。似乎至少有3个其他手势，包括另一个长按手势，预计两次触摸。因此，最好不要设置自己的长按手势需要两次触摸。

在iOS 13中，UILongPressGestureRecognizer仅识别每次触摸的单次长按。您可以尝试将“delaysTouchesBegan”设置为false。
例如：

let longTapGesture = UILongPressGestureRecognizer(target: self, action: #selector(longTap))
longTapGesture.delegate = self
longTapGesture.numberOfTouchesRequired = 1
longTapGesture.cancelsTouchesInView = false
longTapGesture.delaysTouchesBegan = false

mapView.addGestureRecognizer(longTapGesture)

以下是我找到的资源：delaysTouchesBegan Doc