ios - 如何从后台调用 locationManager didUpdateToLocation？
<p><p>嗨，即使应用程序在后台，我也想获取用户的位置，然后我想将该信息上传到数据库，当用户再次运行应用程序时，它会向他显示他访问过的所有地方。所以我读了这篇文章<a href="https://www.raywenderlich.com/92428/background-modes-ios-swift-tutorial" rel="noreferrer noopener nofollow">https://www.raywenderlich.com/92428/background-modes-ios-swift-tutorial</a>并做了作者所说的一切在我添加了后台模式位置更新的功能中，我还在 info.plist 中设置了应用程序不在后台运行为 NO，但我的应用程序仍然没有在后台运行可能是什么问题？ </p>
<pre><code>import UIKit
import CoreLocation
import MapKit
class ViewController: UIViewController, CLLocationManagerDelegate {
var i = 0
@IBOutlet var map: MKMapView!
var backendless = Backendless.sharedInstance()
lazy var locationManager: CLLocationManager = {
let locationManager = CLLocationManager()
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.delegate = self
locationManager.requestAlwaysAuthorization()
locationManager.distanceFilter = kCLDistanceFilterNone
return locationManager
}()
override func viewDidLoad() {
super.viewDidLoad()
locationManager.startUpdatingLocation()
getLocations()
self.map.showsUserLocation = true
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//MARK: -LocationManagerDelegate
//func locationMana
func locationManager(manager: CLLocationManager, didUpdateToLocation newLocation: CLLocation, fromLocation oldLocation: CLLocation) {
let loc = MKPointAnnotation()
loc.coordinate = newLocation.coordinate
savelocation(loc.coordinate.longitude, latitude: loc.coordinate.latitude)
//loc.coordinate.latitude
//map.showAnnotations(loc, animated: true)
}
func savelocation(longitude: Double, latitude: Double){
print("I work \(i)")
i++
let loc1 = locations()
loc1.latitude = String(latitude)
loc1.longitude = String(longitude)
// print(loc1.latitude)
// print(loc1.longitude)
let datastore = backendless.data.of(locations.ofClass())
var error: Fault?
let result = datastore.save(loc1, fault: &error) as? locations
if error == nil{
print("data was saved")
}else{
print("data was not saved")
}
}
func callAlert(message:String!){
let alertController=UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
let OKButton=UIAlertAction(title: "OK", style: .Default, handler: nil)
alertController.addAction(OKButton)
self.presentViewController(alertController, animated: true, completion: nil)
}
func getLocations(){
var arr = ()
//var temp: MKPointAnnotation!
let dataStore = Backendless.sharedInstance().data.of(locations.ofClass())
var error: Fault?
let result = dataStore.findFault(&error)
if error == nil{
let locs = result.getCurrentPage()
// print(cities)
let locs1 = locs as!
if locs1.count - 1 >= 0{
for index in 0...locs1.count - 1{
let temp = MKPointAnnotation()
temp.coordinate.latitude = Double(locs1.latitude!)!
temp.coordinate.longitude = Double(locs1.longitude!)!
arr.append(temp)
}
self.map.addAnnotations(arr)
}
}else{
self.callAlert("There is an error retrieving data")
}
}
}
</code></pre>
<p>我也尝试更改 appdelegate applicationDidEnterBackground 方法，但我不知道如何手动调用该方法。有什么帮助吗？谢谢。 :)我知道这是非法的，应用程序应该自己调用它，但我不知道如何以不同的方式做到这一点</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>您似乎已将您的 <code>locationManager</code> 设置为惰性 var，我假设它在此调用时被初始化:<code>locationManager.startUpdatingLocation()</code>。你应该实现这个方法来开始更新:</p>
<pre><code>func locationManager(manager: CLLocationManager,
didChangeAuthorizationStatus status: CLAuthorizationStatus) {
switch status:
case .AuthorizedAlways:
manager.startUpdatingLocation()
default:
break
}
</code></pre>
<p><strong>注意:</strong>这至少会让您知道您已正确授权您的应用使用用户的位置。你仍然需要一些东西来使用你的 <code>lazy var locationManager</code> 属性来实例化它。我建议改用常规属性，并在 <code>viewDidLoad</code> 中设置您的 <code>locationManager</code>。</p></p>
<p style="font-size: 20px;">关于ios - 如何从后台调用 locationManager didUpdateToLocation？，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/39435696/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/39435696/
</a>
</p>
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