Question

我正在开发一个小型地图应用程序，到目前为止，我有代码删除地图引脚并保存它们，以便在重新打开应用程序后它们保留，此类用于主视图控制器：

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate, UISearchBarDelegate, UIPopoverPresentationControllerDelegate {

    var location: CLLocation!
    let locationManager = CLLocationManager()

    @IBOutlet weak var placesMap: MKMapView!
    @IBOutlet weak var addButton: UIBarButtonItem!
    @IBOutlet weak var moreStuff: UIButton!

    // Popover button action
    @IBAction func moreStuff(sender: AnyObject) {
        self.performSegueWithIdentifier("showMoreStuff", sender:self)
        moreStuff.adjustsImageWhenHighlighted = false
    }

    @IBAction func addButton(sender: AnyObject) {
        let annotation = MKPointAnnotation()
        annotation.coordinate = CLLocationCoordinate2D(latitude: self.placesMap.userLocation.coordinate.latitude, longitude: self.placesMap.userLocation.coordinate.longitude)
        self.placesMap.addAnnotation(annotation)
        self.locationManager.startUpdatingLocation()
    }

    // Location function
    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        let location = locations.last
        let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
        let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.004, longitudeDelta: 0.004))
        self.placesMap?.setRegion(region, animated: true)
        self.locationManager.stopUpdatingLocation()
        let locationDictionary:[String:Double] = ["latitude":center.latitude,"longitude":center.longitude]
        var locationArray = [[String:Double]]()
        if NSUserDefaults.standardUserDefaults().objectForKey("locationArray") != nil {
             locationArray = NSUserDefaults.standardUserDefaults().objectForKey("locationArray") as! [[String:Double]]
    }
        locationArray.append(locationDictionary)
        NSUserDefaults.standardUserDefaults().setObject(locationArray, forKey: "locationArray")
        NSUserDefaults.standardUserDefaults().synchronize()
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        self.locationManager.delegate = self
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
        self.locationManager.requestWhenInUseAuthorization()
        self.locationManager.startUpdatingLocation()
        self.placesMap?.showsUserLocation = true
        if NSUserDefaults.standardUserDefaults().objectForKey("locationArray") != nil {
            for dictionary in NSUserDefaults.standardUserDefaults().objectForKey("locationArray") as! [[String:Double]]{
                let center = CLLocationCoordinate2D(latitude: dictionary["latitude"]!, longitude: dictionary["longitude"]!)
                let annotation = MKPointAnnotation()
                annotation.coordinate = center
                self.placesMap?.addAnnotation(annotation)
            }
        }
    }

我想添加一个按钮，允许所有引脚（存储器）立即复位。此按钮位于新场景和类上，称为“PopoverOptions”。我从类中有以下代码应该这样做，但它似乎没有起作用，因为一旦用户按下它就没有引脚从地图上消失！

@IBOutlet weak var resetMemories: UIButton!

@IBAction func resetMemories(sender: AnyObject) {
    func removeStoredLocations(){
        NSUserDefaults.standardUserDefaults().removeObjectForKey("locationArray")
        NSUserDefaults.standardUserDefaults().synchronize()
    }
}

知道为什么没有移除引脚？我已确保该类正确链接以及按钮outlet / action。

Answer 1

清除用户默认密钥，但不要更改显示这些引脚的视图控制器上的地图视图。您需要调用removeAnnotations从地图中删除注释。

您可以添加一个viewWillAppear方法，检测您的注释是否已被删除并删除它们。像这样：

response.data

如果从userDefaults中删除了整个注释字典，则编写上述代码仅从地图中删除注释。这样，每次视图控制器重新获得焦点时，都可以避免重新加载注释。

顺便说一下，你说过你的新场景叫做＃34; PopoverOptions。＆＃34;如果场景以弹出框形式显示，则上述内容可能无效。（我不认为当一个弹出窗口被解除时，viewWillAppear会被一个视图控制器调用，但我肯定不会记得。）

重置已保存的地图引脚，iOS Swift

1 个答案: