Only number and dot character should allowed in UITextField in Swift3 iOS - ios

Question

I am doing validation on my UITextField. It should accept only number and . character. Basically user can enter any decimal number like :
1.0
1.23
1.45
12.47
Also I have to add % sign while editing in textfield like below:
When User enter 1, textfield should update 1 %
When User enter 1.2, textfield should update 1.2 %
When User enter 18.345, textfield should update 18.345 %
I am using below Code to achieve this:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool{
if string.characters.count == 0 {
return true
}
do {
if textField == self.questionTextFeild {
let nString = textField.text as NSString?
let newString = nString?.replacingCharacters(in: range, with: string)
let expression = "^([0-9]+)?(\\.([0-9]{1,8})?)?$"
let regex = try NSRegularExpression(pattern: expression, options: .caseInsensitive)
let numberOfMatches = regex.numberOfMatches(in: newString! as String, options: [], range: NSRange(location: 0, length: (newString?.characters.count)!))
//textField.text = textField.text!
if numberOfMatches == 0 {
return false
}
}
}
catch let error {
}
return true
}
Using this I can able to enter numbers and dot character. My problem is how can I add % sign? Please suggest me.

Answer 1

Please find the updated code for adding percentage to last of the number while typing
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool{
if string.count == 0 {
return true
}
do {
if textField == textField {
let nString = textField.text as NSString?
let newString = nString?.replacingCharacters(in: range, with: string)
if var textString = textField.text {
let unitString = " %"
if textString.contains(unitString) {
textString = textString.replacingOccurrences(of: unitString, with: "")
textString += string + unitString
textField.text = textString
} else {
textField.text = string + unitString
}
}
let expression = "^([0-9]+)?(\\.([0-9]{1,8})?)?$"
let regex = try NSRegularExpression(pattern: expression, options: .caseInsensitive)
let numberOfMatches = regex.numberOfMatches(in: newString! as String, options: [], range: NSRange(location: 0, length: (newString?.count)!))
//textField.text = textField.text!
if numberOfMatches == 0 {
return false
}
}
}
catch let error {
print(error.localizedDescription)
}
return true
}