ios - Swift 3.0 map 返回到以前的 MapView

Question

我有一个带有注释的 mapView，当单击它时，它会移动到一个新的 viewController。然后，当用户选择从详细信息披露返回到 mapView 时，我希望 mapView 具有与用户在单击详细信息披露之前相同的 View 。以下是我到目前为止设置的代码，但是，当用户从详细信息披露中单击返回时， map 会缩小。我不确定如何重新创建以前的 View 。

详细披露 VC:

// here by segueing, I want to communicate to the MapView VC that the map should remain the same  
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "backButtonTapped" )
    {
        let destinationVC = segue.destination as! TabBarVC
        mapStatus = "wentBack"
        print("The value of mapStatus after seguing is \(mapStatus)")
        destinationVC.selectedIndex = 1

    }

}

map View VC:

 override func viewDidAppear(_ animated: Bool) {
    // here if the mapStatus is not the correct value (the user never used the detail disclosure), the map will just snap onto the current location

    if mapStatus == "wentBack" {
       print("Do not update location")

       // assuming appropriate code is placed here but I am not sure what it is


    } else {
        print("Updated Current Location")
    let center = CLLocationCoordinate2D(latitude: self.lastLocation.coordinate.latitude, longitude: self.lastLocation.coordinate.longitude)
    let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))

    map.setRegion(region, animated: true)

        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        if #available(iOS 8.0, *) {
            locationManager.requestAlwaysAuthorization()
        } else {
            // Fallback on earlier versions
        }
        let noLocation = CLLocationCoordinate2D()
        let viewRegion = MKCoordinateRegionMakeWithDistance(noLocation, 200, 200)
        map.setRegion(viewRegion, animated: false)

    }
    }

Answer 1

事实证明， map 不会持续存在，因为当用户返回详细信息披露时调用 viewDidLoad(使用 prepareForSegue)。我用过

@IBAction func backButtonTapped(_ sender: UIBarButtonItem) {
    self.dismiss(animated: true)
    mapStatus = "wentBack"

} 

为了关闭 viewController，只调用 viewDidAppear 而不是 viewDidLoad。