UITextField - uneditable prefixed characters both in beginning & end - ios

Question

I have a UITextField, and I want to give it uneditable characters. For example I have "Hello...", and I want the user to write in between o and . such as "Hello userTypedStuff..."
I used this approach, however with that, user can longpress the beginning and for example go to the position inside Hello. Thus, user can mess with the prefixed characters.
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let protectedRange = NSMakeRange(0, 5)
let intersection = NSIntersectionRange(protectedRange, range)
if intersection.length > 0 {
return false
}
if range.location == 12 {
return true
}
if range.location + range.length > 12 {
return false
}
return true
}
How can I setup something like 'uneditable first 5 characters and last 3 characters'?
Edit: The UITextField's text-aligned center and is forming above a UILabel. However, if I give textField the width of label, textField won't get larger on width. Thus, I gave its width view's width. Is there a way I can create UILabel on both ends having Hello and ... separately, and have textField (with text-aligned center) in the middle which automatically stretches width?
Edit 2:
If I have my textview with two static UILabels on both sides, that can be a workaround. However, this time the UITextField won't push UILabels to sides as user starts to type in. The TextField center textAligned. If I give it a constant width while creating it (programatically with CGRectMake) , it won't stretch its width as user types in. Thus, I gave it the width of view. Is there a way to auto-stretch the TextField's width as user types in that pushes the UILabels on the sides?
"Hello" [textfield] "..."
uilabel uilabel

Answer 1

class SpecialTextField: UITextField {
// MARK: - UITextField Observing
override internal func willMoveToSuperview(newSuperview: UIView!) {
if newSuperview != nil {
text = "Hello..."
addTarget(self, action: #selector(SpecialTextField.didChangeText), forControlEvents: .EditingChanged)
}
}
override internal func canPerformAction(action: Selector, withSender sender: AnyObject?) -> Bool {
return false
}
private var newVal: String = "Hello..."
func didChangeText() {
var userDidEditDefaultValue = true
if (text?.characters.count > 7) { // Count of "Hello..."
if text?.rangeOfString("Hello") != nil {
if text?.rangeOfString("...") != nil {
userDidEditDefaultValue = false
}
}
}
if userDidEditDefaultValue {
text = newVal
}
newVal = text ?? "Hello..."
}
}
This will not allow user to change default value of "Hello..." OR "Hello userEntry..."
You can use delegate method to insert text in the middle.
Hope it helped.