how to append % sign after input
extension ViewController: UITextFieldDelegate {
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let currentText = textField.text! as NSString
let newText = currentText.replacingCharacters(in: range, with: string)
if newText.hasSuffix("%"){
textField.text = newText
}else{
textField.text = "\(newText) %"
}
return true
}
}
as in the picture i just want 1 % sign after the numbers.
https://developer.apple.com/documentation/uikit/uitextfielddelegate/1619599-textfield says:
Return Value: true if the specified text range should be replaced;
otherwise, false to keep the old text.
probably because you return true swift updates with the old text replacing the text property of the text-field you just set. Try returning false as this 'keeps the old text' which is already updated by your code.
The reason is func shouldChangeCharactersIn call before the text is input so it is wrong. What we want in here is after the value changed, add % at the end if not have. Here is the code for do that.
// add action for value change recognized
textField.addTarget(self, action: #selector(didChangeValueTextField(textField:)), for: .editingChanged)
#objc final private func didChangeValueTextField(textField: UITextField)
{
let text = textField.text ?? ""
if !text.hasSuffix("%") {
textField.text! = text + "%"
// make cursor position to be left 1 index because final index is %
let newPosition = textField.position(from: textField.endOfDocument, offset: -1)!
textField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)
}
}
Related
I have a UITextField validate that converts a user's numeric input. For example, if the user types in a 1, it becomes 0.01. If the user types 12, it becomes 0.12.
My code is working correctly when I have the validation code in textFieldDidEndEditing. However, I've been asked to rewrite the code a bit so that the validation occurs as the user is typing as opposed to when they're finished with the textfield, so it makes sense to use shouldChangeCharactersInRange. However, I'm a little confused how to write my code now.
Old code (working):
func textFieldDidEndEditing(_ textField: UITextField) {
if var text = textField.text,
let float = Float(text) {
let formattedFloat = float/100
if let formatterExists = formatter {
text = String.localizedStringWithFormat("\(String(describing: formatterExists))", formattedFloat)
}
let numericString = text.replacingOccurrences(of: ",", with: "")
cellModel.stringInput = numericString
}
}
New code (not working):
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if let float = Float(string) {
let formattedFloat = float/100
var text = string
if let formatterExists = formatter {
text = String.localizedStringWithFormat("\(String(describing: formatterExists))", formattedFloat)
}
let numericString = text.replacingOccurrences(of: ",", with: "")
print(numericString)
textField.text = text
cellModel.stringInput = numericString
}
return false
}
I know that in my shouldChangeCharactersInRange code, everytime I type a character, it is taking that character and applying the validation, and only doing it for a single character (as in if I type 1, I get a 0.01, and if I type a 2, the previous character gets replaced and I get a 0.02).
I'm wondering what is a good method for a user to be able to continuously input a number and keep having the validation applied as the user types.
Thanks!
I am creating a trivia application that asks for a username on start up. I'd like to make it impossible to use characters such as #$#!^& etc (also including "space"). I took a look at this post here but it is written entirely in Objective-C. Thanks in advance.
Swift 4 iOS 11.2.x based on using an extension, tests to see if a string is a valid hex number in this example.
extension String {
var containsValidCharacter: Bool {
guard self != "" else { return true }
let hexSet = CharacterSet(charactersIn: "1234567890ABCDEFabcdef")
let newSet = CharacterSet(charactersIn: self)
return hexSet.isSuperset(of: newSet)
}
}
You use it like with the UITextFieldDelegate.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return (string.containsValidCharacter)
}
Although I read in an earlier post that CharacterSets do not support characters that are composed of more than one Unicode.Scalar; so use with caution I guess.
Since you're explicitly asking for Swift, I've translated the top asnwer in the linked question.
let notAllowedCharacters = " ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_.";
func textField(
textField: UITextField,
shouldChangeCharactersInRange range: NSRange,
replacementString string: String)
-> Bool
{
let set = NSCharacterSet(charactersInString: notAllowedCharacters);
let inverted = set.invertedSet;
let filtered = string
.componentsSeparatedByCharactersInSet(inverted)
.joinWithSeparator("");
return filtered != string;
}
internal func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool{
if let text = string{
if text == "#" || text == "$" || text == "!"{ \\and so on
return false
}
}
return true
}
Swift 2.3
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let characters = ["#", "$", "!", "&","#"]
for character in characters{
if string == character{
print("This characters are not allowed")
return false
}
}
}
So this is probably the most robust way to restrict Spaces. Using this user won't be able to Paste/Type Whitespaces
This is how you can Implement using Swift 3.
Add below mentioned extension snippet to a Swift file;
extension String {
var containsWhitespace: Bool {
for scalar in unicodeScalars {
switch scalar.value {
case 0x20:
return true
default:
continue
}
}
return false
}
}
In your ViewController Swift file drag out your Editing Changed Instance and a Referencing Outlet of UITextField from Storyboard, the one mentioned in picture below:
Use the dragged Instances as mentioned below:
Referencing Outlet as:
#IBOutlet weak var textField: UITextField!
and Editing Changed as:
#IBAction func textChanged(_ sender: UITextField) {
if (textField.text!.containsWhitespace) == true {
print("Restrict/Delete Whitespace")
emailField.deleteBackward()
} else {
print("If Its not Whitespace, Its allowed.")
}
}
This will detect and remove whitespace as soon as user tries to type/paste it.
Swift 4 iOS 11.2.x based on using an extension, tests to see if a string is a valid hex number in this example.
extension String {
var containsValidCharacter: Bool {
guard self != "" else { return true }
let hexSet = CharacterSet(charactersIn: "1234567890ABCDEFabcdef")
let newSet = CharacterSet(charactersIn: self)
return hexSet.isSuperset(of: newSet)
}
}
You use it like with the UITextFieldDelegate.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return (string.containsValidCharacter)
}
Swift : 3 and a different approach:
Add a target function for the text field change in your viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
textField.addTarget(self, action: #selector(ViewController.textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
}
in the target function, simply detect the entered char and replace it with blank. I have tested it and it prevents the user from entering any non desirable characters in the text field.
func textFieldDidChange(textField: UITextField) {
if let textInField = textField.text{
if let lastChar = textInField.characters.last{
//here include more characters which you don't want user to put in the text field
if(lastChar == "*")
{
textField.text = textInField.substring(to: textInField.index(before: textInField.endIndex))
}
}
}
}
Adding on to what #Evdzhan Mustafa said. You want to add a return statement in case the string is empty. Without it you won't be able to delete your text. Modified Code Below:
Swift 3 Version
let notAllowedCharacters = " ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_.";
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if string.isEmpty{
return true
}
print("String: \(string)")
let set = NSCharacterSet(charactersIn: notAllowedCharacters);
let inverted = set.inverted;
let filtered = string.components(separatedBy: inverted).joined(separator: "")
print("String Filtered: \(filtered)")
return filtered != string;
}
enter image description hereI have managed to prevent the user from entering more than 2 digits in the 'month' field, using a text delegate function:
Swift code
However, I also want to prevent the user entering a number greater than 12. Can anyone point me in the right direction?
Thanks!
Add Int(myString) < 13 in your return condition with && operator.
in didload
txt_field.delegate=self
txt_field.addTarget(self, action:"submit:", forControlEvents: UIControlEvents.EditingChanged)
then define "submit" method as
#IBAction func submit(sender: AnyObject) {
let a:Int? = txt_field.text.toInt()
if a > 12{
print("number is greater than 12")
}
else{
print("number is less than 12")
}
}
"submit" method is called each time user stops editing the textfield. Hence you can check what user is entering and prevent him from entering value greater than 12.
Hope it helps.
Happy Coding.
textEdit.delegate = self from your view controllar
extension UserProfileViewController: UITextFieldDelegate {
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let numberFiltered = string.components(separatedBy: NSCharacterSet(charactersIn: "0123456789").inverted).joined(separator: "")
guard string == numberFiltered, range.location < 2 else {
return false
}
if let newValue = textField.text?.intValue, let currentValue = string.intValue {
let totalValue = newValue*10 + currentValue
switch totalValue {
case 16..<80:
return true
default:
textField.text = ""
return false
}
}
return true
} }
I want to limit the number of characters a user can use in a textField. I took a function from this link: Max length UITextField (Imanou Petit)
However, in my viewDidLoad() I have several textFields that I'm already referencing the delegate because I want the keyboard to "Return" when the user presses the Return key on the keyboard. This I'm doing through the textFieldShouldReturn like this (I also have a touchesBegan method but I want the user to also have the option of the Return key):
func textFieldShouldReturn(textField: UITextField!) -> Bool {
self.stuffOneTextField.resignFirstResponder()
self.linkTextField.resignFirstResponder()
self.descriptionTextField.resignFirstResponder()
self.ogTextField.resignFirstResponder()
self.priceTextField.resignFirstResponder()
return true
}
If I add in this function below to the viewDidLoad, then the 'Return' key on the keyboard doesn't work and it limits ALL of the textFields (I have 5).
override func viewDidLoad() {
super.viewDidLoad()
self.stuffOneTextField.delegate = self
self.linkTextField.delegate = self
self.descriptionTextField.delegate = self
self.ogTextField.delegate = self
self.priceTextField.delegate = self
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
guard let text = textField.text else { return true }
let newLength = text.characters.count + string.characters.count - range.length
return newLength <= limitLength
}
I only need to limit 2 textFields. I've tried just putting in the specific textField name instead of all the textFields as textFields and then it limits 1 textField and doesn't let me type in the others... Very strange...
How do I go around this?
Any help means a lot.
You're being given the textField that is changing characters in the delegate function. Here, you can compare it to the specific fields that you want to limit:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
guard let text = textField.text else { return true }
if !(textField == stuffOneTextField || textField == descriptionTextField) {
return true
}
let newLength = text.characters.count + string.characters.count - range.length
return newLength <= limitLength
}
Also, func textFieldShouldReturn(textField: UITextField!) -> Bool is giving you a text field, and you can call resignFirstResponder() on that, if that is what you want to do there.
I'm having a problem regarding the creation of a prefix inside a UITextField using the new Swift language. Currently I have created the UITextField using the Interface Builder and I have assigned an IBOutlet to it, named usernameField, then using the textFieldDidBeginEditing function I write a NSMutableAttributedString inside it, named usernamePrefix, containing only the word "C-TAD-" and finally I limited the UITextField max characters number to 13, like so:
class ViewController: UIViewController, UITextFieldDelegate {
#IBOutlet var usernameField : UITextField!
private var usernamePrefix = NSMutableAttributedString(string: "C-TAD-")
func textFieldDidBeginEditing(textField: UITextField) {
if textField == usernameField {
if usernameField.text == "" {
usernameField.attributedText = usernamePrefix
}
}
usernameField.addTarget(self, action: "textFieldDidChangeText:", forControlEvents:UIControlEvents.EditingChanged)
}
func textField(textField: UITextField!, shouldChangeCharactersInRange range: NSRange, replacementString string: String!) -> Bool {
let maxUsernameLength = countElements(usernameField.text!) + countElements(string!) - range.length
return maxUsernameLength <= 13
}
override func viewDidLoad() {
super.viewDidLoad()
usernameField.delegate = self
passwordField.delegate = self
}
}
Now, how can I assign new parameters to the usernamePrefix in order to have to give 2 different colors to the text written in the UITextField? I would like to have the prefix in .lightGreyColor() and the rest in .blackColor(). Also how can I make the usernamePrefix un-editable and un-deletable by the user?
Thanks for the help
Simpler option would be to set leftView of the UITextField and customise it how you like it:
let prefix = UILabel()
prefix.text = "C-TAD-"
// set font, color etc.
prefix.sizeToFit()
usernameField.leftView = prefix
usernameField.leftViewMode = .whileEditing // or .always
It is un-editable and un-deletable and you don't need to do any calculations to check the length of the input.
For the first part, you can refactor your delegate method as follow.
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
//This makes the new text black.
textField.typingAttributes = [NSForegroundColorAttributeName:UIColor.blackColor()]
let protectedRange = NSMakeRange(0, 6)
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
}
This will lock down both the length at 13 and the prefix can not be deleted. Everything typed will be UIColor.blackColor()
Then you can a method like the following in your viewDidLoad, to set the prefix.
func makePrefix() {
let attributedString = NSMutableAttributedString(string: "C-TAD-")
attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.lightGrayColor(), range: NSMakeRange(0,6))
textField.attributedText = attributedString
}
I've adopted the solution from Jeremy and make a little bit improvement to make it a bit more swifty, and also handle the case when user pastes multiple characters into the text field.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let protectedRange = NSRange(location: 0, length: usernamePrefix.length)
let intersection = protectedRange.intersection(range)
// prevent deleting prefix
if intersection != nil {
return false
}
// limit max character count
if (textField.text ?? "").count + string.count > 13 {
return false
}
return true
}