function - 快速访问函数外部的变量

Question

我从 获取坐标，但我希望能够在位置管理器功能之外使用它们。是否可以使它们成为实例变量？如果是这样，有人可以给我一些示例代码吗？在下面的代码中，我在 func 中打印并且它有效，但我希望能够，例如在它之外打印，或者使用坐标。也许作为一个全局变量？我将如何编码？我无法从文档中完全理解。

import UIKit
import CoreLocation
import MapKit

class ViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {

  var locationManager: CLLocationManager!
  var seenError : Bool = false
  var theSpan: MKCoordinateSpan = MKCoordinateSpanMake(0.1, 0.1)
  var locationStatus : NSString = "Not Started"

  var initialLoc:Int = 1

  override func viewDidLoad() {
    super.viewDidLoad()

    locationManager = CLLocationManager()
    locationManager.requestAlwaysAuthorization()
    locationManager.delegate = self
    var initialLoc:Int = 1
    // Do any additional setup after loading the view, typically from a nib.
  }

  @IBOutlet weak var Map: MKMapView!
  @IBAction func Here(sender: AnyObject) {       
    initLocationManager()
  }

  func initLocationManager() {
    seenError = false
    locationManager = CLLocationManager()
    locationManager.delegate = self
    locationManager.startUpdatingLocation()
    Map.showsUserLocation = true
  }

  func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {

    var locationArray = locations as NSArray
    var locationObj = locationArray.lastObject as CLLocation
    var coord = locationObj.coordinate
    if initialLoc == 1 {
        var Region:MKCoordinateRegion = MKCoordinateRegionMake(coord, theSpan)
        self.Map.setRegion(Region, animated:true)
        initialLoc = 0
    }
    println(coord.latitude)
    println(coord.longitude)
  }

  // Location Manager Delegate stuff
  // If failed
  func locationManager(manager: CLLocationManager!, didFailWithError error: NSError!) {
    locationManager.stopUpdatingLocation()
    if (error) {
        if (seenError == false) {
            seenError = true
            print(error)
        }
     }
  }

  override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
  }
}

Answer 1

如果我对您的理解正确，我认为最好的选择是将其设为实例变量，如您所说。这将通过在类顶部使用其他实例变量在函数外部声明它来完成(星号用于向您显示我添加的内容):

 class ViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {
    
    var locationManager: CLLocationManager!
    var seenError : Bool = false
    var theSpan: MKCoordinateSpan = MKCoordinateSpanMake(0.1, 0.1)
    var locationStatus : NSString = "Not Started"
    
    var initialLoc:Int = 1

// Declare coordinate variable
 ***var coord: CLLocationCoordinate2D?***

问号将变量声明为 optional ，因此您不必立即为其赋值。
然后，您将 locationObj.coordinate 值分配给 locationManager 函数中的 coord，但是因为您已经声明了 函数外的 coord 变量作为实例变量，您可以删除 var coord = locationObj.coordinate 中的 var :

    func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
    
        var locationArray = locations as NSArray
        var locationObj = locationArray.lastObject as CLLocation

        //Assign value to coord variable
     ***coord = locationObj.coordinate***

        if initialLoc == 1 {
            var Region:MKCoordinateRegion = MKCoordinateRegionMake(coord, theSpan)
            self.Map.setRegion(Region, animated:true)
            initialLoc = 0
        }

然后您可以在函数的其余部分正常使用该变量，以及类中的任何其他函数(如全局变量)。
祝你好运!
附言学习如何做好这件事，因为这是处理函数和变量时一直使用的方法