use of unresolved identifier 'result' swift 3 - swift

Question

I'm writing a login page for my app and i'm getting this error
social media app , xcode 8.3.2 , swift 3
i've tried target membership in file inspector and nothing changed
also I removed test units (UITest and Test) and renew them , it didn't worked either.
at the line 41 I'm getting this error "use of unresolved identifier 'result'"
the picture below explains the code
Picture
import UIKit
class LoginViewController : UIViewController
{
#IBOutlet weak var txt_username: UITextField!
#IBOutlet weak var txt_password: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
#IBAction func btn_log_in_click(_ sender: Any){
let server=MultipartUtility (Url:"http://x.x.x.x/appname-api/user/login/")
//I.m hiding the real ip and details for posting this
server.AddFormField("username", value: txt_username.text)
server.AddFormField("password", value: txt_password.text)
let task = URLSession.shared.dataTask(with: server.execute())
{Data,URLResponse,error in
if error != nil{
print(error as Any)
return
}
do{
let json = try JSONSerialization.jsonObject(with: Data!, options: .allowFragments)
if let json_result = json as? [String: Any]{
let result = json_result ["result"] as? String
if result == "0"
{
DispatchQueue.main.async {
let alert = UIAlertController(title:"Incorrect Username",message : "The username you entered doesn't appear to belong to an account. Please check your username and try again", preferredStyle : .alert)
let alert_action = UIAlertAction(title: "Try Again", style: .default, handler: nil)
alert.addAction(alert_action)
self.present(alert, animated: true, completion: nil)
}
}
}
else{
DispatchQueue.main.async {
UserDefaults.standard.set(result!, forKey: "user_id")
//" use of unresolved identifier 'result' "
let current_view=UIApplication.shared.windows[0] as UIWindow
let new_view=(self.storyboard? .instantiateViewController(withIdentifier: "tab_bar"))! as UIViewController
UIView.transition(from: (current_view.rootViewController? .view)!, to:new_view.view , duration: 0.65, options: .transitionFlipFromRight, completion: {(action) in current_view.rootViewController=new_view
})
}
}
}
catch{
}
}
task.resume()
}
}

Answer 1

if let json_result = json as? [String: Any]
{
let result = json_result ["result"] as? String
if result == "0"
{
DispatchQueue.main.async {
let alert = UIAlertController(title:"Incorrect Username",message : "The username you entered doesn't appear to belong to an account. Please check your username and try again", preferredStyle : .alert)
let alert_action = UIAlertAction(title: "Try Again", style: .default, handler: nil)
alert.addAction(alert_action)
self.present(alert, animated: true, completion: nil)
}
}
else
{
DispatchQueue.main.async {
UserDefaults.standard.set(result!, forKey: "user_id")
//" use of unresolved identifier 'result' "
let current_view=UIApplication.shared.windows[0] as UIWindow
let new_view=(self.storyboard? .instantiateViewController(withIdentifier: "tab_bar"))! as UIViewController
UIView.transition(from: (current_view.rootViewController? .view)!, to:new_view.view , duration: 0.65, options: .transitionFlipFromRight, completion: {(action) in current_view.rootViewController=new_view
})
}
}
}
else{
// Error in jsonSerialization
}