Location Manager didEnterRegion和didExitRegion方法不会被调用

Question

我已经做了几个月的iOS开发，最近我正在开发一个公交应用。

我目前正在模仿公共汽车的运动，并在公共汽车站设置多个注释。出于测试目的，我只设置了一个公共汽车站，并试图监视公共汽车何时进入该区域并退出。

奇怪的是，我的didStartMonitoringForRegion方法被完美地调用了，但didEnterRegion和didExitRegion方法都没有被调用。与此同时，不会调用任何错误。每次我运行这个程序，公共汽车几乎都没有提示我过站。

有人能解释一下为什么会发生这种情况以及如何解决它吗?

//  ViewController.swift
//  Parta Service
//  Created by Emil Shirima on 8/24/15.
//  Copyright (c) 2015 Emil Shirima. All rights reserved.
import UIKit
import MapKit
import CoreLocation
class ViewController: UIViewController, MKMapViewDelegate,   CLLocationManagerDelegate {
@IBOutlet weak var mapView: MKMapView!
let locationManager = CLLocationManager()
var allBusAnnotations = [MKPointAnnotation]()
var summitEastBusStations = [CLLocationCoordinate2D]()
var busStopNames = ["Dix Stadium", "Risman Plaza", "Terrace Drive", "Terrace Drive 2","C-Midway","Theatre Dr.","East Main Street","South Lincoln"]
var radius = 250 as CLLocationDistance
// 0.02 is the best zoom in factor
var mapZoomInFactor : Double = 0.02
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    self.getBusStop()
    self.locationManager.delegate = self
    // gets the exact location of the user
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
    // gets the user's location only when the app is in use and not background
    self.locationManager.requestWhenInUseAuthorization()
    self.locationManager.startUpdatingLocation()
    self.mapView.showsUserLocation = true
    self.setBusStopAnnotations(summitEastBusStations)
    self.canDeviceSupportAppBackgroundRefresh()
}
override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
    // sends the latitude and longitude to the Apple Servers then returns the address
    CLGeocoder().reverseGeocodeLocation(manager.location, completionHandler: { (placeMarks: [AnyObject]!, error: NSError!) -> Void in
        if error != nil
        {
            println("Reverse Geocode Failed: " + error.localizedDescription)
            println("The real reason is " + error.localizedFailureReason!)
            return
        }
        if placeMarks.count > 0
        {
            // gets the most updated location
            let pm = placeMarks.last as! CLPlacemark
            let centre = CLLocationCoordinate2D(latitude: manager.location.coordinate.latitude, longitude: manager.location.coordinate.longitude)
            // draws a circle in which the map will zoom to
            let region = MKCoordinateRegion(center: centre, span: MKCoordinateSpan(latitudeDelta: self.mapZoomInFactor, longitudeDelta: self.mapZoomInFactor))
            self.mapView.setRegion(region, animated: true)
            self.displayLocationInfo(pm)
            self.geoFencing()
        }
    })
}
func displayLocationInfo(placemark: CLPlacemark)
{
    println("Current Location:")
    println(placemark.name)
}
func locationManager(manager: CLLocationManager!, didFailWithError error: NSError!) {
    println("Location Manager Failed: " + error.localizedDescription)
}
func locationManager(manager: CLLocationManager!, didStartMonitoringForRegion region: CLRegion!) {
    println("The monitored regions are: (locationManager.monitoredRegions)")
}
func locationManager(manager: CLLocationManager!, monitoringDidFailForRegion region: CLRegion!, withError error: NSError!) {
    println("Failed to monitor the stated region")
}
func locationManager(manager: CLLocationManager!, didEnterRegion region: CLRegion!) {
    println("The bus has entered the region")
    createAlert("Region Entry", alertMessage: "You have entered the specified region", alertCancelTitle: "OK")
}
func locationManager(manager: CLLocationManager!, didExitRegion region: CLRegion!) {
    println("The bus has left the region")
    createAlert("Region Exit", alertMessage: "You have exited the specified region", alertCancelTitle: "OK")
}
//TODO:Implement GeoFencing in order to know when the bus is at a station or not.
func geoFencing()
{
    locationManager.requestAlwaysAuthorization()
    let rismanPlaza = CLLocationCoordinate2D(latitude: 41.1469492, longitude: -81.344068)
    var currentBusStop = CLLocation(latitude: rismanPlaza.latitude, longitude: rismanPlaza.longitude)
    addRadiusCircle(currentBusStop)
    let busStopRegion = CLCircularRegion(center: CLLocationCoordinate2D(latitude: rismanPlaza.latitude, longitude: rismanPlaza.longitude), radius: radius, identifier: busStopNames[1])
    if radius > self.locationManager.maximumRegionMonitoringDistance
    {
        radius = self.locationManager.maximumRegionMonitoringDistance
    }
    if CLLocationManager.isMonitoringAvailableForClass(CLCircularRegion)
    {
        locationManager.startMonitoringForRegion(busStopRegion)
    }
    else
    {
        //TODO: Create an alert telling the user that region tracking for this area is not available
        println("Monitoring is not available for this region")
    }
}
// creates the radius around the specified location
func addRadiusCircle(location: CLLocation)
{
    self.mapView.delegate = self
    var circle = MKCircle(centerCoordinate: location.coordinate, radius: radius)
    self.mapView.addOverlay(circle)
}
// performs the actual circle colouring
func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -> MKOverlayRenderer!
{
    if overlay is MKCircle
    {
        var circle = MKCircleRenderer(overlay: overlay)
        circle.strokeColor = UIColor.redColor()
        circle.fillColor = UIColor(red: 255, green: 0, blue: 0, alpha: 0.1)
        circle.lineWidth = 1
        return circle
    }
    else
    {
        return nil
    }
}
// removes the drawn circles from the map
func removeCircleLayers()
{
    var layers = mapView.overlays
    mapView.removeOverlays(layers)
}
func canDeviceSupportAppBackgroundRefresh()
{
    if UIApplication.sharedApplication().backgroundRefreshStatus == UIBackgroundRefreshStatus.Available
    {
        createAlert("Background Refresh Status", alertMessage: "Background Updates are enable for the App", alertCancelTitle: "OK")
    }
    else if UIApplication.sharedApplication().backgroundRefreshStatus == UIBackgroundRefreshStatus.Denied
    {
        createAlert("Background Refresh Status", alertMessage: "Background Updates are disabled by the user for the App", alertCancelTitle: "OK")
    }
    else if UIApplication.sharedApplication().backgroundRefreshStatus == UIBackgroundRefreshStatus.Restricted
    {
        createAlert("Background Refresh Status", alertMessage: "Background Updates are restricted and the user can't do anything App", alertCancelTitle: "OK")
    }
}
func createAlert(alertTitle: String, alertMessage: String, alertCancelTitle: String)
{
    let alert = UIAlertView(title: alertTitle, message: alertMessage, delegate: self, cancelButtonTitle: alertCancelTitle)
    alert.show()
}
}

Answer 1

我最终使用了CLRegion.containsCoordinate(location.coordinate)方法。它的工作原理基本相同。

一旦对象进入我设置的区域，它返回true，从这里我可以知道它何时进入和退出该区域

Answer 2

如果用户设备处于当前位置(纬度和经度)，didEnterRegion:和didExitRegion:委托将不会触发。使用didDetermineState:方法来查找用户/设备是否处于被监控的当前区域。如果是，didDetermineState:将被触发。一旦用户离开区域didExitRegion:将被触发