unexpectedly found nil while unwrapping an Optional value for my UITextField - json

Question

I'm having trouble passing the JSON values (I'm reading successfully) into my textfield on the next viewcontroller because of this unwrapping error, stating my text field is nil.
I'm very stuck. Here's my class that reads the JSON:
class DoOAuth
{
func doOAuthFitbit() -> String{
var name = ""
let oauthswift = OAuth1Swift(
consumerKey: "eabf603efe9e45168d057b60b03f8e94",
consumerSecret: "46b4dfa8c9d59666769e03f887d531a8",
requestTokenUrl: "https://api.fitbit.com/oauth/request_token",
authorizeUrl: "https://www.fitbit.com/oauth/authorize?display=touch",
accessTokenUrl: "https://api.fitbit.com/oauth/access_token")
oauthswift.authorizeWithCallbackURL( NSURL(string: "fitbit://oauth")!,
success:{
credential, response in
let vc: ViewController = ViewController()
let user: OAuthSwiftClient = OAuthSwiftClient(consumerKey: oauthswift.consumer_key, consumerSecret: oauthswift.consumer_secret, accessToken: credential.oauth_token, accessTokenSecret: credential.oauth_token_secret)
let object:[String : AnyObject] = ["oauth_token": credential.oauth_token, "oauth_token_secret" : credential.oauth_token_secret]
user.get("https://api.fitbit.com/1/user/-/profile.json", parameters: object,
success: {
(data: NSData, response: NSHTTPURLResponse) -> Void in
let jsonValues = JSON(data: data, options: NSJSONReadingOptions.AllowFragments, error: nil)
println(jsonValues)
/*public var dictionary: [Swift.String: JSON]?
{
switch self
{
case .Dictionary(let d):
var jsonObject: [Swift.String: JSON] = [:]
for(k,v) in d
{
jsonObject[k] = JSON.wrap(v)
}
return jsonObject
default:
return nil
}
}*/
for(key, subJson) in jsonValues
{
if let nm = subJson["fullName"].string
{
println("\(nm)")
name = nm
}
}
/*for(index: String, subJson: JSON) in jsonValues
{
let name = subJson.dictionary?["fullName"]?.string
println("\(name!)")
//vc.nm.text = name!
main.acceptJson(name!)
}*/
},
failure: {
(error:NSError!) -> Void in
println(error.localizedDescription)
println("error")
})
},
failure: {
(error:NSError!) -> Void in
println(error.localizedDescription)
})
return name
}
}
I call a function that is supposed to receive the JSON strings (acceptJson) located in the next view controller:
class mainMenu: UIViewController
{
var oauthfitbit: DoOAuth = DoOAuth()
var name = ""
//let vc: ViewController = ViewController()
#IBOutlet weak var lbl: UILabel!
#IBOutlet weak var nameField: UITextField!{
didSet{
nameField.text = name
}
}
override func viewWillAppear(animated: Bool)
{
//name = oauthfitbit.doOAuthFitbit()
//self.nameField.text = "Working"
//self.nameField.text = name
}
func acceptJson(info: String!)
{
println("\(info)")
self.nameField.text = info
//name = info
}
}
I get the excepting thrown on the setting nameField.text line stating nameField is nil. How do I get the textfield to store the JSON string?
And here's the initial View Controller:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBOutlet weak var nm: UITextField!
//let main: mainMenu = mainMenu()
var name = ""
#IBAction func connectPressed(sender: UIButton)
{
var oauthFitbit: DoOAuth = DoOAuth()
name = oauthFitbit.doOAuthFitbit()
self.performSegueWithIdentifier("loginSuccess", sender: nil)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "loginSuccess")
{
let controller = segue.destinationViewController as! mainMenu
controller.name = name
//vc.nameField.text = "Hello"
}
}
}

Answer 1

How did you create your textfield? Was it through Interface Builder? There have been plenty of times when I've run into these type of problems when using Interface Builder and IBOutlets.
The first step is to make sure your text field is connected to your view controller from the .xib file correctly. Delete the connection and reconnect by control (command?) dragging from IB to your view controller code.
If you're not using IB and still having problems, post the code where you create the textfield. You have to set your view controller as the text field delegate if you're creating it programmatically, I believe. It's been awhile since I've done it that way.
Let us know!

Answer 2

The easiest way to get the new view controller the value of nm is in prepareForSegue:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "YourIdentifier" {
let controller = segue.destinationViewController as! mainMenu
controller.name = name
}
}
So, to get this to work, you will need to add a name instance variable (var name = "") to your first view controller, and change main.acceptJson(nm) to name = nm.
Once name is set in your first view controller, you can segue to the second view controller.
In the second view controller, you can change your text field outlet to this:
#IBOutlet weak var nameField: UITextField! {
didSet {
nameField.text = name
}
}
The didSet is a property observer. You can't set the nameField text field directly from the first view controller's prepareForSegue because the text field isn't set up yet when prepareForSegue is called in the first view controller. That's why you're storing it in an instance variable. Then, because of the didSet, your text field's text property will be set as soon as it comes into existence.
UPDATE:
The following is in a class of its own. Let's call that class DoOAuth (looks like that's what you called it):
class DoOAuth {
func doOAuthFitbit() -> String { // Now it's returning a string
var name = "" // Create local variable to return
let oauthswift = OAuth1Swift(
consumerKey: "eabf603efe9e45168d057b60b03f8e94",
consumerSecret: "46b4dfa8c9d59666769e03f887d531a8",
requestTokenUrl: "https://api.fitbit.com/oauth/request_token",
authorizeUrl: "https://www.fitbit.com/oauth/authorize?display=touch",
accessTokenUrl: "https://api.fitbit.com/oauth/access_token")
oauthswift.authorizeWithCallbackURL( NSURL(string: "fitbit://oauth")!,
success:{
credential, response in
//let vc: ViewController = ViewController() // Get rid of this
let user: OAuthSwiftClient = OAuthSwiftClient(consumerKey: oauthswift.consumer_key, consumerSecret: oauthswift.consumer_secret, accessToken: credential.oauth_token, accessTokenSecret: credential.oauth_token_secret)
let object:[String : AnyObject] = ["oauth_token": credential.oauth_token, "oauth_token_secret" : credential.oauth_token_secret]
user.get("https://api.fitbit.com/1/user/-/profile.json", parameters: object,
success: {
(data: NSData, response: NSHTTPURLResponse) -> Void in
let jsonValues = JSON(data: data, options: NSJSONReadingOptions.AllowFragments, error: nil)
println(jsonValues)
/*public var dictionary: [Swift.String: JSON]?
{
switch self
{
case .Dictionary(let d):
var jsonObject: [Swift.String: JSON] = [:]
for(k,v) in d
{
jsonObject[k] = JSON.wrap(v)
}
return jsonObject
default:
return nil
}
}*/
for(key, subJson) in jsonValues
{
if let nm = subJson["fullName"].string
{
println("\(nm)")
name = nm // Store 'nm' in local variable declared above
}
}
}
return name
} // end doOAuthFitbit()
} // end class
Now change your connectPressed() method in ViewController to this:
#IBAction func connectPressed(sender: UIButton)
{
var oauthFitbit: DoOAuth = DoOAuth()
name = oauthFitbit.doOAuthFitbit() // doOAuthFitbit() now returns a String
self.performSegueWithIdentifier("loginSuccess", sender: nil)
}
Now it should work.