Switching between Text fields on pressing return key in Swift

I'm designing an iOS app and I want that when the return key is pressed in my iPhone it directs me to the next following text field.

I have found a couple of similar questions, with excellent answers around but they all just happen to be in Objective-C and I'm looking for Swift code, now this is what I have up until now:

func textFieldShouldReturn(emaillabel: UITextField) -> Bool{
    return true
}

It's placed in the file that's connected and controller to the UIView that contains the text fields, but I'm not sure if thats the right place.

Okay, so I tried this out and got this error:
//could not find an overload for '!=' that accepts the supplied arguments

func textFieldShouldReturn(textField: UITextField) -> Bool {
    let nextTag: NSInteger = textField.tag + 1
    // Try to find next responder
    let nextResponder: UIResponder = textField.superview!.viewWithTag(nextTag)!
    if (nextResponder != nil) {
        // could not find an overload for '!=' that accepts the supplied arguments

        // Found next responder, so set it.
        nextResponder.becomeFirstResponder()
    } else {
        // Not found, so remove keyboard.
        textField.resignFirstResponder()
    }
    return false // We do not want UITextField to insert line-breaks.
}

Solution

Make sure your UITextField delegates are set and the tags are incremented properly. This can also be done through the Interface Builder.

Here's a link to an Obj-C post I found: How to navigate through textfields (Next / Done Buttons)

class ViewController: UIViewController,UITextFieldDelegate {
   // Link each UITextField (Not necessary if delegate and tag are set in Interface Builder)
   @IBOutlet weak var someTextField: UITextField!

   override func viewDidLoad() {
      super.viewDidLoad()
      // Do the next two lines for each UITextField here or in the Interface Builder
      someTextField.delegate = self
      someTextField.tag = 0 //Increment accordingly
   }

   func textFieldShouldReturn(_ textField: UITextField) -> Bool {
      // Try to find next responder
      if let nextField = textField.superview?.viewWithTag(textField.tag + 1) as? UITextField {
         nextField.becomeFirstResponder()
      } else {
         // Not found, so remove keyboard.
         textField.resignFirstResponder()
      }
      // Do not add a line break
      return false
   }
}