[英]How to use dispatch_async in Swift?
我想向服务器发送一些数据,但是当我尝试时,出现此错误
我认为调度存在问题,可能是我没有正确使用它,但是我没有使用xcode或swift的经验,所以我不知道如何很好地理解日志错误窗口,欢迎您的帮助,您的时间不多
这是我的代码:
func updateAndDismiss6() {
SharingManager.sharedInstance.FinalDiag = self.Diag.text!
SharingManager.sharedInstance.TreatmentDays = self.Trata.text!
SharingManager.sharedInstance.SystematicTreat = self.TrataSu.text!
SharingManager.sharedInstance.LidoPatch = self.ParcheLido.text!
}
@IBAction func IrResumen(sender: AnyObject) {
updateAndDismiss6()
let prefs = NSUserDefaults.standardUserDefaults()
let userid = prefs.stringForKey("userid")! as String
let Inicial = SharingManager.sharedInstance.Initials
let Edad = SharingManager.sharedInstance.Age
let Resultados = SharingManager.sharedInstance.Result
let Diagnostico = SharingManager.sharedInstance.FinalDiag
let Ttratamiento = SharingManager.sharedInstance.TreatmentDays
let TsUsado = SharingManager.sharedInstance.SystematicTreat
let Plidocaina = SharingManager.sharedInstance.LidoPatch
if ( Inicial == "" || Edad == "" || Resultados == "" || Diagnostico == "" || Ttratamiento == "" || TsUsado == "" || Plidocaina == "" || userid == "") {
let alertView:UIAlertView = UIAlertView()
alertView.title = "No data"
alertView.message = "error de datos"
alertView.delegate = self
alertView.addButtonWithTitle("OK")
alertView.show()
}
else {
let url_servicio = "http://arasoftltda.com/grunenthal/app/muestra.php"
let request = NSMutableURLRequest(URL: NSURL(string: url_servicio)!)
request.HTTPMethod = "POST"
//let postString = "nombre=pruebafromios&email=pruebafromios@pruebafromios.com®istro=registro&esp=esp&pais=Colombia&ciudad=Cogua&contrasena=123"
let postString = "iniciales=\(Inicial)&edad=\(Edad)&resultado=\(Resultados)&diagnostico=\(Diagnostico)&dias=\(Ttratamiento)&tratamiento=\(TsUsado)&parche=\(Plidocaina)&id=\(userid)"
request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding)
let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { data, response, error -> Void in
if (error != nil){
print(error!.localizedDescription)
} else{
let nsdata:NSData = NSData(data: data!)
do{
let json = try NSJSONSerialization.JSONObjectWithData(nsdata, options: NSJSONReadingOptions.MutableContainers)
let id = json["id"] as! String
if (id != ""){
print (id)
dispatch_async(dispatch_get_main_queue()) {
[unowned self] in
self.performSegueWithIdentifier("Resumen", sender: self)}
}
}
catch{
print("Error del JSON")
let alertView:UIAlertView = UIAlertView()
alertView.title = "Fallo al enviar datos!"
alertView.message = "Error de conexion con el servidor"
alertView.delegate = self
alertView.addButtonWithTitle("OK")
alertView.show()
}
}
}
task.resume()
}
}
您的错误消息告诉您它试图从后台线程更新UI(在本例中为自动布局约束)。 堆栈跟踪中存在大量UIAlertView
和UIAlertController
引用,这告诉您问题的根源是UIAlertView
。
最重要的是,所有UI更新必须分派到主队列。 因此,除了将performSegueWithIdentifier
调度到主队列之外,您还必须将UIAlertView
/ UIAlertController
调度到主队列。
func showError() {
dispatch_async(dispatch_get_main_queue()) { [unowned self] in
let ac = UIAlertController(title: "Loading error", message: "There was a problem loading the feed; please check your connection and try again.", preferredStyle: .Alert)
ac.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
self.presentViewController(ac, animated: true, completion: nil)
}
}
您在执行segue时正在这样做。 显示警报时尝试同样的事情!
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