ios - 如何将点击与注释匹配(或比较)？

Question

环境

• Xcode 8
• Swift 3

问题陈述

我希望能够确定用户是否点击 MKPointAnnotation，然后从该注释中提取信息(例如 title 和 subtitle)以供使用在我的应用程序中。
我想这并不是非常困难，但是我对我需要做什么/需要使用哪些类/对象/方法/等来做到这一点感到有点迷失。
所以我寻找指针/指导 - 欢迎代码，但在这一点上，指针/指导对我来说将是向前迈出的重要一步。

代码片段

到目前为止代码的删节版本(试图将其限制为仅相关部分)

class NewLocationViewController: UIViewController, CLLocationManagerDelegate, UITextFieldDelegate {

    //... various @IBOutlet's for text fields, buttons, etc. ...
    @IBOutlet weak var map:         MKMapView!

    var coords:            CLLocationCoordinate2D?
    var locationManager:   CLLocationManager = CLLocationManager()
    var myLocation:        CLLocation!
    var annotation:        MKPointAnnotation!
    var annotationList:    [MKPointAnnotation] = []
    var matchingItems:     [MKMapItem] = [MKMapItem]()

    override func viewDidLoad() {
        super.viewDidLoad()

        //... text field delegates, and other initilizations ...
        locationManager.requestWhenInUseAuthorization()
        if CLLocationManager.locationServicesEnabled() {
            locationManager.desiredAccuracy = kCLLocationAccuracyBest
            locationManager.delegate        = self
        }
        myLocation       = nil
        //... other initializations...
    }

    // Search for things that match what my app is looking for ("<search string>")
    func performSearch() {
        annotationList.removeAll() // clear list
        matchingItems.removeAll()  // clear list 
        var closest                  = MKMapItem()
        var distance                 = 10000.0
        let request                  = MKLocalSearchRequest()
        let span                     = MKCoordinateSpan(latitudeDelta: 0.001, longitudeDelta: 0.001)
        request.naturalLanguageQuery = "<search string>"
        request.region               = MKCoordinateRegionMake(myLocation.coordinate, span)
        let search                   = MKLocalSearch(request: request)

        if search.isSearching {
            search.cancel()
        }
        search.start(completionHandler: {
            (_ response, _ error) in
            if error != nil {
                self.showAlert(msg: "Error occurred in search\nERROR: \(error?.localizedDescription)")
            }
            else if response!.mapItems.count == 0 {
                self.showAlert(msg: "No matches found") 
            }
            else {
                for item in response!.mapItems {

                    // Track the closest placemark to our current [specified] location
                    let (distanceBetween, prettyDistance) = self.getDistance(loc1: self.myLocation, loc2: item.placemark.location!)
                    let addrObj                           = self.getAddress(placemark: item.placemark)
                    //... some code omitted ...

                    // Add markers for all the matches found
                    self.matchingItems.append(item as MKMapItem)
                    let annotation        = MKPointAnnotation()
                    annotation.coordinate = item.placemark.coordinate
                    annotation.title      = item.name
                    annotation.subtitle   = "\(addrObj.address!) (\(prettyDistance))"
                    self.map.addAnnotation(annotation)
                    self.annotationList.append(annotation) 
                }

                //... some code omitted ...
            }
        })
    }

    //... code for getDistance(), getAddress() omitted for brevity - they work as designed ...
    //... other code omitted as not being relevant to the topic at hand
}

我想我需要重写 touchesEnded 和可能的 touchesBegan 以及 touchesMoved 才能检测到点击。
我不知道如何将 touch 的位置(在屏幕上表示为 X/Y 坐标)与 MKPointAnnotation 或 MKMapItem< 进行比较 的位置(在 map 上表示为纬度/经度坐标)
所以 - 这就是我目前陷入困境的地方。我在网上搜索了各种术语，但找不到任何[简单地]回答我的问题的内容 - 并且以 Swift 代码格式(有许多帖子看起来可能有帮助，但是所提供的代码不是用 Swift 编写的，我不会那么容易地进行翻译)。

更新(东部时间 19:48)

我找到这篇文章: How do I implement the UITapGestureRecognizer into my application并尝试遵循它，但是...

我稍微修改了代码(添加了UIGestureRecognizerDelegate):

class NewLocationViewController: UIViewController, CLLocationManagerDelegate, UITextFieldDelegate, UIGestureRecognizerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        //...other code...
        let tapHandler = UITapGestureRecognizer(target: self, action: Selector(("handleTap:"))) //<<<== See notes below
        tapHandler.numberOfTapsRequired    = 1
        tapHandler.numberOfTouchesRequired = 1
        tapHandler.delegate                = self
        print("A")//#=#
        map.addGestureRecognizer(tapHandler)
        map.isUserInteractionEnabled       = true
        print("B")//#=#
    }

    func handleTap(tap: UITapGestureRecognizer) {
        print("ARRIVED")//#=#
        let here = tap.location(in: map)
        print("I AM HERE: \(here)")//#=#
    }

    //...
}

关于tapHandler的声明/定义，我尝试了以下方法:

    let tapHandler = UITapGestureRecognizer(target: self, action: "handleTap:")
    let tapHandler = UITapGestureRecognizer(target: self, action: Selector("handleTap:")) 
    let tapHandler = UITapGestureRecognizer(target: self, action: Selector(("handleTap:"))) // supresses warning

前两个导致 Xcode 中显示警告，最后一个只是抑制警告:

[W] No method declared with Objective-C selector 'handleTap:'

当我运行我的应用程序并点击图钉时 - 我在日志中收到以下内容:

A
B
libc++abi.dylib: terminating with uncaught exception of type NSException

(对我来说)这似乎表明 viewDidLoad 中的一般设置没问题，但是一旦它尝试处理点击，它就会死掉而不会到达我的 handleTap 函数 - 因此警告(如上所示)似乎要严重得多。

所以，我不确定我是否可以算作取得了进展，但我正在努力......

Answer 1

感谢这个MKAnnotationView and tap detection我找到了解决方案。我的代码与最初发布的代码相比发生了变化:

class NewLocationViewController: UIViewController, CLLocationManagerDelegate, UITextFieldDelegate, UIGestureRecognizerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        //...other code...
        let tapHandler = UITapGestureRecognizer() //<<<== No parameters
        tapHandler.numberOfTapsRequired    = 1
        tapHandler.numberOfTouchesRequired = 1
        tapHandler.delegate                = self
        map.addGestureRecognizer(tapHandler)
        map.isUserInteractionEnabled       = true
    }

    // Not sure who calls this and requires the Bool response, but it seems to work...
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        return self.handleTap(touch: touch).count > 0
    }

    // Major Changes
    private func handleTap(touch: UITouch) -> [MKAnnotationView] {
        var tappedAnnotations: [MKAnnotationView] = []
        for annotation in self.map.annotations {
            if let annotationView: MKAnnotationView = self.map.view(for: annotation) {
                let annotationPoint = touch.location(in: annotationView)
                if annotationView.bounds.contains(annotationPoint) {
                    self.name.text    = annotationView.annotation?.title!
                    let addr          = AddrInfo(composite: ((annotationView.annotation?.subtitle)!)!)
                    self.address.text = addr.street!
                    self.city.text    = addr.city!
                    self.state.text   = addr.state!
                    self.zipcode.text = addr.zip!
                    tappedAnnotations.append(annotationView)
                    break
                }
            }
        }
        return tappedAnnotations
    }

    //...
}

AddrInfo 片段是我自己的小子类，除其他外，它采用类似“1000 Main St., Pittsburgh, PA 15212, United States”的字符串，并且将其分成单独的部分，以便可以单独访问它们(如上面的代码所示)。

可能有一种更简单或更好的方法来实现我正在寻找的目标 - 但上述确实实现了它，所以我认为它是我的问题的答案。