阵列“CoreLocation”

Question

我试图显示用户的平均速度， 我还想显示数组的最高值。

我在论坛上搜索并找到了许多方法来实现这一点，但没有任何作用。

我尝试过的是// top speed和// average speed

这是我的代码：

// Location
let manager = CLLocationManager()

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let location = locations[0]
    let span = MKCoordinateSpanMake(0.015, 0.015)
    let myLocation = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)

    let region = MKCoordinateRegionMake(myLocation, span)
    mapView.setRegion(region, animated: true)
    self.mapView.showsUserLocation = true

    // Altitude
    let altitude = location.altitude
    let altitudeNoDecimals = Int(altitude)

    altitudeLabel.text = "\(altitudeNoDecimals)"

    // m/s to km/h
    let kmt = location.speed * (18/5)
    let kmtLabel = Int(kmt)
    statusLabel.text = "\(kmtLabel)"

    // Top Speed
    // let maxSpeed: Int = (kmtLabel as AnyObject).value(forKeyPath: "@maxSpeed.self") as! Int
    // topSpeedLabel.text = "\(maxSpeed)"

    let max = location.toIntMax()
    topSpeedLabel.text = "\(max)"

    // Average speed
    var avg: Double = (list as AnyObject).valueForKeyPath("@avg.self") as Double
    averageSpeed.text = "\(avg)"
}

override func viewDidLoad() {
    super.viewDidLoad()
    manager.delegate = self
    manager.desiredAccuracy = kCLLocationAccuracyBest
    manager.requestWhenInUseAuthorization()
    manager.startUpdatingLocation()
}

Answer 1

您必须自己将所有速度更新保存到数组中，应将其定义为类实例属性，并且您可以将平均速度和最高速度定义为计算属性，这样您就不需要手动更新它们每次收到位置更新。

let manager = CLLocationManager()
var speeds = [CLLocationSpeed]()
var avgSpeed: CLLocationSpeed {
    return speeds.reduce(0,+)/Double(speeds.count) //the reduce returns the sum of the array, then dividing it by the count gives its average
}
var topSpeed: CLLocationSpeed {
    return speeds.max() ?? 0 //return 0 if the array is empty
}

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let location = locations[0]
    ...

    speeds.append(contentsOf: locations.map{$0.speed}) //append all new speed updates to the array

    // m/s to km/h
    let kmt = location.speed * (18/5)
    let kmtLabel = Int(kmt)
    statusLabel.text = "\(kmtLabel)"

    // Top Speed
    topSpeedLabel.text = "\(topSpeed)"

    // Average speed
    averageSpeed.text = "\(avgSpeed)"
}

请记住，我没有将avgSpeed或topSpeed的单位更改为km / h，如果您需要，可以先将其写入标签或而是在将它们附加到数组之前。