appManager首次运行时执行locationManager(_:更改授权:)

Question

每当应用程序首次运行时,是否会调用位置管理器(_:执行更改授权:),即使已经调用了位置管理器方法requestWhenInUseAuthorization()或startUpdatingLocation()？我正试图通过点击我在下面的@IBAction中调用的按钮来报告位置:

@IBAction func findOutPressed(_ sender: UIButton) {
    getLocation()
}

我的CoreLocation代码位于以下扩展中:

extension ViewController: CLLocationManagerDelegate {
    
    // Called from findOutPressed to get location when button is clicked
    func getLocation() {
        let status = CLLocationManager.authorizationStatus()
        handleLocationAuthorizationStatus(status: status)
    }
    
    // Respond to the result of the location manager authorization status
    func handleLocationAuthorizationStatus(status: CLAuthorizationStatus) {
        switch status {
        case .notDetermined:
            locationManager.requestWhenInUseAuthorization()
        case .authorizedWhenInUse, .authorizedAlways:
            locationManager.startUpdatingLocation()
        case .denied:
            print("I'm sorry - I can't show location. User has not authorized it")
        case .restricted:
            print("Access denied - likely parental controls are restricting use in this app.")
        }
    }
    
    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        handleLocationAuthorizationStatus(status: status)
    }
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        
        let currentLocation = locations.last
        
        let labelText = "My location is: latitude = \((currentLocation?.coordinate.latitude)!), longitude = \((currentLocation?.coordinate.longitude)!)"
        
        resultLabel.text = labelText
        
        locationManager.stopUpdatingLocation()
    }
    
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print("Dang, there was an error! Error: \(error)")
    }
}

我发现位置管理器(确实更改授权:)正在执行,即使没有通过点击触发@IBAction findOutPressed,结果也会在我最初的空白结果之前更新.用户点击了按钮.我知道我可以设置一个标志来确定按钮是否被点击,防止标签过早更新,但我试图理解何时触发位置管理器(_:更改授权).Apple说:"只要应用程序使用位置服务的能力发生变化,就会调用此方法.由于用户允许或拒绝为您的应用程序或整个系统使用位置服务,因此可能会发生更改." 这似乎不包括应用程序首次运行时触发的情况.我很感激任何能够让我直接理解授权变更发生的事情的人.抱歉,如果我错过了一些基本的东西.谢谢!

Answer 1

didChangeAuthorization 在创建CLLocationManager时调用,所以即使这将触发:

var locationManager = CLLocationManager()
// ...
locationManager?.delegate = self
// ...
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
    print( "authorization checked..." )
}

那么您可能正在AppDelegate的顶部设置和初始化您的locationManager？这会触发它.然后会发生的事情是didChangeAuthorization开始更新位置,然后在实际点击按钮之前调用你的didUpudateLocation.

也许将locationManager声明为findOutPressed()中的可选且唯一的init,例如:

// class var:
var locationManager:CLLocationManager?location managers,
// ...
@IBAction func findOutPressed(_ sender: UIButton) {
    locationManager = CLLocationManager()
    locationManager?.delegate = self

    getLocation()
}