Swift 3 Solution, using ordered array of UITextField's
func nextTextField() {
let textFields = // Your textfields array
for i in 0 ..< textFields.count{
if let textfield = textFields[i], textfield.isFirstResponder{
textfield.resignFirstResponder()
if i+1 < textFields.count, let nextextfield = textFields[i+1]{
nextextfield.becomeFirstResponder()
return
}
}
}
}