下面是我的代码。我想要我的后字符串中的纬度和经度值。但是当他执行 poststring 时，我的值仍然为零，因为 swift 还没有更新位置。那么在 poststring 获取值之前如何等待纬度和经度呢？我听说过 didset，但我不知道如何使用它以及在哪里必须使用它。
import Foundation
import CoreLocation
protocol FeedmodelProtocol: class {
func itemsDownloaded(items: NSArray)
}
class Feedmodel: NSObject, URLSessionDataDelegate, CLLocationManagerDelegate {
weak var delegate: FeedmodelProtocol!
let locationManager = CLLocationManager() // create Location Manager object
var latitude : Double?
var longitude : Double?
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location: CLLocationCoordinate2D = manager.location?.coordinate else { return }
// set the value of lat and long
latitude = location.latitude
longitude = location.longitude
}
func downloadItems() {
self.locationManager.requestAlwaysAuthorization()
// For use in foreground
// You will need to update your .plist file to request the authorization
self.locationManager.requestWhenInUseAuthorization()
if CLLocationManager.locationServicesEnabled() {
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
locationManager.startUpdatingLocation()
}
let myUrl = URL(string: "http://example.com/stock_service4.php");
let defaultSession = Foundation.URLSession(configuration: URLSessionConfiguration.default)
var request = URLRequest(url:myUrl!)
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.httpMethod = "POST"
var postString = ""
if let lat = latitude, let long = longitude {
locationManager.stopUpdatingLocation()
postString = "lati=\(Int(lat))&longi=\(Int(long))"
// do task here now that postString is not empty
}
request.httpBody = postString.data(using: .utf8)
let task = defaultSession.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else { // check for fundamental networking error
print("error=\(String(describing: error))")
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 { // check for http errors
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(String(describing: response))")
print("error=\(String(describing: error))")
}
let responseString = String(data: data, encoding: .utf8)
print("responseString = \(String(describing: responseString))")
print("error=\(String(describing: error))")
self.parseJSON(data)
}
task.resume()
}
func parseJSON(_ data:Data) {
var jsonResult = NSArray()
do{
jsonResult = try JSONSerialization.jsonObject(with: data, options:JSONSerialization.ReadingOptions.allowFragments) as! NSArray;
} catch let error as NSError {
print(error)
}
var jsonElement = NSDictionary()
let stocks = NSMutableArray()
for i in 0 ..< jsonResult.count
{
print(jsonResult)
jsonElement = jsonResult[i] as! NSDictionary
let stock = Stockmodel()
//the following insures none of the JsonElement values are nil through optional binding
if let Datum = jsonElement["Datum"] as? String,
let Tankstelle = jsonElement["Tankstelle"] as? String,
let Kraftstoff1 = jsonElement["Kraftstoff1"] as? String,
let Preis1 = jsonElement["Preis1"] as? String,
let Kraftstoff2 = jsonElement["Kraftstoff2"] as? String,
let Preis2 = jsonElement["Preis2"] as? String,
let Notiz = jsonElement["Notiz"] as? String,
let longitude = jsonElement["longitude"] as? String,
let latitude = jsonElement["latitude"] as? String
{
print (Datum)
print(Tankstelle)
print(Kraftstoff1)
print(Preis1)
print(Kraftstoff2)
print(Preis2)
print(Notiz)
print(longitude)
print(latitude)
stock.Datum = Datum
stock.Tankstelle = Tankstelle
stock.Kraftstoff1 = Kraftstoff1
stock.Preis1 = Preis1
stock.Kraftstoff2 = Kraftstoff2
stock.Preis2 = Preis2
stock.Notiz = Notiz
stock.longitude = longitude
stock.latitude = latitude
}
stocks.add(stock)
}
DispatchQueue.main.async(execute: { () -> Void in
self.delegate.itemsDownloaded(items: stocks)
})
}
}
谢谢!
最佳答案
每次更新位置时都会调用函数locationManager(_:didUpdateLocations:)。因此，您应该在位置管理器中添加 downloadItems() ，如下所示:
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location: CLLocationCoordinate2D = manager.location?.coordinate else { return }
// set the value of lat and long
latitude = location.latitude
longitude = location.longitude
downloadItems()
}
See the documentation about locationManager(_:didUpdateLocations:)
关于php - 如何在执行函数之前等待 Swift 中的变量？ ( swift )，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51012861/