以下应用程序应获取用户的当前位置,然后使用 OpenWeatherMap 显示该位置的名称和温度。
import UIKit
import CoreLocation
class ViewController: UIViewController, CLLocationManagerDelegate {
@IBOutlet weak var location: UILabel!
@IBOutlet weak var temperature: UILabel!
var locationManager: CLLocationManager = CLLocationManager()
var startLocation: CLLocation!
func extractData(weatherData: NSData) {
let json = try? NSJSONSerialization.JSONObjectWithData(weatherData, options: []) as! NSDictionary
if json != nil {
if let name = json!["name"] as? String {
location.text = name
}
if let main = json!["main"] as? NSDictionary {
if let temp = main["temp"] as? Double {
temperature.text = String(format: "%.0f", temp)
}
}
}
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let latestLocation: AnyObject = locations[locations.count - 1]
let lat = latestLocation.coordinate.latitude
let lon = latestLocation.coordinate.longitude
// Put together a URL With lat and lon
let path = "http://api.openweathermap.org/data/2.5/weather?lat=\(lat)&lon=\(lon)&appid=2854c5771899ff92cd962dd7ad58e7b0"
print(path)
let url = NSURL(string: path)
let task = NSURLSession.sharedSession().dataTaskWithURL(url!) { (data, response, error) in
dispatch_async(dispatch_get_main_queue(), {
self.extractData(data!)
})
}
task.resume()
}
func locationManager(manager: CLLocationManager,
didFailWithError error: NSError) {
}
override func viewDidLoad() {
super.viewDidLoad()
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.delegate = self
locationManager.requestWhenInUseAuthorization()
locationManager.startUpdatingLocation()
startLocation = nil
}
}
我一直在学习如何按照本教程从 OpenWeatherMap 获取数据: https ://www.youtube.com/watch?v=r-LZs0De7_U
该应用程序在以下位置崩溃:
self.extractData(data!)
由于 data 等于 nil,这不应该发生,因为当我将打印的路径复制并粘贴到我的 Web 浏览器中时,数据就在那里。我确定我正确地遵循了教程,那么问题是什么,我该如何解决?