Samah Ahmed Samah Ahmed - 2 months ago 99
Swift Question

Error during read JSON file in Swift 3

I use this code in all my projects in swift 2.2 but when I created new project after updated xcode to xcode 8 I faced this problem in reading JSON file with this code

do {


let comURL = "mylinkhere"+"customer_key=\(self.customer_key)"


// NSLog("PostData: %@",post)

let regURL:NSURL = NSURL(string: comURL)!


//let postData:NSData = post.dataUsingEncoding(NSASCIIStringEncoding)!

//let postLength:NSString = String( postData.length )

let request:NSMutableURLRequest = NSMutableURLRequest(url: regURL as URL)
request.httpMethod = "POST"
//request.HTTPBody = postData
//request.setValue(postLength as String, forHTTPHeaderField: "Content-Length")
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.setValue("application/json", forHTTPHeaderField: "Accept")

var reponseError: NSError?
var response: URLResponse?

var urlData: NSData?

do {
urlData = try NSURLConnection.sendSynchronousRequest(request as URLRequest, returning:&response) as NSData?
// print(urlData)
} catch let error as NSError {
reponseError = error
urlData = nil
}

if ( urlData != nil ) {

let res = response as! HTTPURLResponse!;

//NSLog("Response code: %ld", res?.statusCode);

if ((res?.statusCode)! >= 200 && (res?.statusCode)! < 300)
{
let responseData:NSString = NSString(data:urlData! as Data, encoding:String.Encoding.utf8.rawValue)!

NSLog("Response Data ==> %@", responseData );

//var error: NSError?

let jsonData = try JSONSerialization.jsonObject(with: urlData! as Data, options: .allowFragments) as! [String:AnyObject]




self.Appstatus = (jsonData as AnyObject).value("android_app_status") as! NSString



self.StreamURL = (jsonData as AnyObject).value("android_streaming_url") as! NSString

//[jsonData[@"success"] integerValue];

// NSLog("App Status2: %@", self.Appstatus);
// NSLog("App Stream URL2: %@", self.StreamURL);

if(self.Appstatus == "true")

{


}

else{

}


}

} else {
let alertView:UIAlertView = UIAlertView()
alertView.title = "Sign in Failed!"
alertView.message = "Connection Failure"
if let error = reponseError {
alertView.message = (error.localizedDescription)
}
alertView.delegate = self
alertView.addButton(withTitle: "OK")
alertView.show()
}

} catch {
let alertView:UIAlertView = UIAlertView()
alertView.title = "Sign Up Failed!"
alertView.message = "Server Error!"
alertView.delegate = self
alertView.addButton(withTitle: "OK")
alertView.show()
}


I got the response correctly but the error in these two line when trying to retrieve data from result

self.Appstatus = (jsonData as AnyObject).value("android_app_status") as! NSString


self.StreamURL = (jsonData as AnyObject).value("android_streaming_url") as! NSString


The error is:
enter image description here

Answer

In Swift 3 most of the AnyObject types has been changed to Any

Basically in Swift

  • do not use valueForKey to get a value for a dictionary key, use key subscription.
  • do not cast types up (as AnyObject) after casting them down (pretty counterproductive).
  • do not use Foundation NSString. Use Swift String.

    let jsonData = try JSONSerialization.jsonObject(with: urlData! as Data,  options: .allowFragments) as! [String:Any]
    self.Appstatus = jsonData["android_app_status"] as! String
    self.StreamURL = jsonData["android_streaming_url"] as! String
    

If the keys are not guaranteed to exist use optional bindings to avoid a runtime error.

And finally do not use deprecated synchronous URL loading API.