Textfield is not formatted once populated with data - ios

I have a textfield for numbers that is already formatted when user types in the field; it would look like this:
Here is my code:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
phoneNumberTextField.delegate = self
retrieveUserData()
}
func formattedNumber(number: String) -> String {
let cleanPhoneNumber = number.components(separatedBy: CharacterSet.decimalDigits.inverted).joined()
let mask = "(XXX) XXX-XXXX"
var result = ""
var index = cleanPhoneNumber.startIndex
for ch in mask where index < cleanPhoneNumber.endIndex {
if ch == "X" {
result.append(cleanPhoneNumber[index])
index = cleanPhoneNumber.index(after: index)
} else {
result.append(ch)
}
}
return result
}
extension AccounInfotVC: UITextFieldDelegate {
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard let text = textField.text else { return false }
let newString = (text as NSString).replacingCharacters(in: range, with: string)
textField.text = formattedNumber(number: newString)
return false
}
}
However, when my view loads; the number is not formatted once its auto populated from the database with this code:
func retrieveUserData(){
db.collection(DatabaseRef.Users).document(userID).getDocument { (snap, error) in
self.phoneNumberTextField?.text = phoneNumber
}
}
so the number gets populated like this:
instead of this:
Any idea how i can get it to populate the textfield in the same format as when user types?
Note that, when I save the phone number, I remove spaces and the characters so number is saved like 1234567889 in the database.

This
self.phoneNumberTextField?.text = phoneNumber
won't trigger shouldChangeCharactersIn , you need
self.phoneNumberTextField?.text = formattedNumber(number:phoneNumber)

Related

UITextField Autocomplete with max length

Im currently trying to set a max length on a UITextField which works fine as per the UITextField delegate method
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let currentText = textField.text ?? ""
guard let stringRange = Range(range, in: currentText) else { return false }
let updatedText = currentText.replacingCharacters(in: stringRange, with: string)
return updatedText.count <= 9
}
Tthe issue im having is when using autocomplete with some text already input.
For example, the UITextField is set to have the content type of postal code. Everything works fine if i autocomplete a postcode LS27 8LN or similar from an empty UITextField
An example problem is if i have postcode LS already in the UITextField and i autocomplete LS27 9AL the updatedText in the example code is LSLS27 9AL which goes over my max length. The range also has location and length of 0
One thing i've noticed is if i remove the delegate method all together, it seems iOS replaces the current text within the UITextField anyway.
Try this extension of UITextField
import UIKit
private var __maxLengths = [UITextField: Int]()
extension UITextField{
private struct Constants {
static let defaultMaxLength: Int = 150
}
#IBInspectable var maxLength: Int {
get {
guard let len = __maxLengths[self] else {
return Constants.defaultMaxLength
}
return len
}
set {
__maxLengths[self] = newValue
self.addTarget(self, action: #selector(fix), for: .editingChanged)
}
}
#objc func fix(textField: UITextField) {
let text = textField.text
textField.text = text?.safelyLimitedTo(length: maxLength)
}
func safelyLimitedTo(text: String, length n: Int) -> String {
guard n >= 0, text.count > n else {
return text
}
return String( Array(text).prefix(upTo: n) )
}
}
Them set the maxLenght you need, like textField.maxLength = 20

Why is replacingCharacters necessary for changing the text in text field?

I can change my way to present numbers in the text field using the following line of code based on what I type in the text field. But I can't even type in numbers in the second version of my code.
Why
[let oldText = textField.text! as NSString
var newText = oldText.replacingCharacters(in: range, with: string)]
is necessary?
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let oldText = textField.text! as NSString
var newText = oldText.replacingCharacters(in: range, with: string)
var newTextString = String(newText)
let digits = CharacterSet.decimalDigits
var digitText = ""
for c in (newTextString?.unicodeScalars)! {
if digits.contains(UnicodeScalar(c.value)!) {
digitText.append("\(c)")
}
}
// Format the new string
if let numOfPennies = Int(digitText) {
newText = "$" + self.dollarStringFromInt(numOfPennies) + "." + self.centsStringFromInt(numOfPennies)
} else {
newText = "$0.00"
}
textField.text = newText
return false
}
func textFieldDidBeginEditing(_ textField: UITextField) {
if textField.text!.isEmpty {
textField.text = "$0.00"
}
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true;
}
func dollarStringFromInt(_ value: Int) -> String {
return String(value / 100)
}
func centsStringFromInt(_ value: Int) -> String {
let cents = value % 100
var centsString = String(cents)
if cents < 10 {
centsString = "0" + centsString
}
return centsString
}
If I change it like this, it doesn't work anymore.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
var newText = textField.text
let digits = CharacterSet.decimalDigits
var digitText = ""
for c in (newText?.unicodeScalars)! {
if digits.contains(UnicodeScalar(c.value)!) {
digitText.append("\(c)")
}
}
// Format the new string
if let numOfPennies = Int(digitText) {
newText = "$" + self.dollarStringFromInt(numOfPennies) + "." + self.centsStringFromInt(numOfPennies)
} else {
newText = "$0.00"
}
textField.text = newText
return false
}
textField(_:shouldChangeCharactersIn:replacementString:) gets called before the text is replaced inside the text field. This method is used for getting the new text before it's accessible with textField.text.
If you just want to run logic after the replacement happened, observe the notification called .UITextFieldTextDidChange.
NotificationCenter.default.addObserver(self, selector: #selector(textFieldTextDidChange), name: .UITextFieldTextDidChange, object: textField)
func textFieldTextDidChange() {
print(textField.text)
}
"shouldChangeCharactersIn" is called BEFORE the text field is modified. Since your code always returns false, whatever the user has typed in (or pasted in) will not update the field's content unless you do it yourself.
In the second version you are completely ignoring the user's input so your field's value never changes.
Lets answer by part.
1) The method replacingCharacters(in: range, with: string)isn't required. This methods will replace the substring that matches with range specified. So, according with Apple docs:
stringByReplacingCharactersInRange:withString:
Returns a new string in which the characters in a specified range of the receiver are replaced by a given string
2) The real reason the code change don't work is the return value false. Try return true and the change will work. Whenever you set the text field text property, the method textField:shouldChangeCharactersIn:replacementString: will be invoked (since its delegate is assigned). Returning false you are telling the program it should not replace the characters.
UPDATE
Try use the UIControl event Value Changed as an #IBAction instead textField:shouldChangeCharactersIn:replacementString: this will work well.
Obs: Sorry for my english

Validate Entry In TextField

I have a textfield which allows the user to input text and saves this text to a variable and stores it in user defaults. I need the input to be a string therefore I need the textfield to detect the input as being anything but a string. How can I do this?
You can use this code
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let characterSet = NSCharacterSet.letters
return (string.rangeOfCharacter(from: characterSet) != nil)
}
make sure you have set delegate for your textfield properly
Try this code. Hope it helps you.
func updateSaveButtonState() {
let text = titleTextField.text ?? ""
saveButton.isEnabled = !text.isEmpty
}
#IBAction func textEditingChanged(_ sender: UITextField) {
updateSaveButtonState()
}
#IBAction func returnPressed(_ sender: UITextField) {
titleTextField.resignFirstResponder()
}
try with below code: swift 4.0
func validateOnlyLetters(text: String) -> Bool {
let characterSet = CharacterSet.decimalDigits
return (text.rangeOfCharacter(from: characterSet) == nil)
}
by default, textField.text property is a string.
if you don't want the users to enter any numbers, you may refer to this post to vaidate the input before saving into userdefaults.
another post in Swift - How can I check if a string contains letters in Swift?
let letters = NSCharacterSet.letterCharacterSet()
let phrase = "Test case"
let range = phrase.rangeOfCharacterFromSet(letters)
// range will be nil if no letters is found
if let test = range {
println("letters found")
}
else {
println("letters not found")
}

Set the maximum character length of a UITextField in Swift

I know there are other topics on this, but I can't seem to find out how to implement it.
I'm trying to limit a UITextField to only five characters.
Preferably alphanumeric, -, ., and _.
I've seen this code:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange,
replacementString string: String) -> Bool
{
let maxLength = 4
let currentString: NSString = textField.text
let newString: NSString =
currentString.stringByReplacingCharactersInRange(range, withString: string)
return newString.length <= maxLength
}
and
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let length = count(textField.text.utf16) + count(string.utf16) - range.length
return length <= 10
}
How can I actually implement it? Which "textfield" should I swap out for my custom named UITextField?
Your view controller should conform to UITextFieldDelegate, like below:
class MyViewController: UIViewController, UITextFieldDelegate {
}
Set the delegate of your textfield: myTextField.delegate = self
Implement the method in your view controller:
textField(_:shouldChangeCharactersInRange:replacementString:)
All together:
class MyViewController: UIViewController, UITextFieldDelegate // Set delegate to class
#IBOutlet var mytextField: UITextField // textfield variable
override func viewDidLoad() {
super.viewDidLoad()
mytextField.delegate = self // set delegate
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange,
replacementString string: String) -> Bool
{
let maxLength = 4
let currentString: NSString = textField.text
let newString: NSString = currentString.stringByReplacingCharactersInRange(range, withString: string)
return newString.length <= maxLength
}
For Swift 4
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let maxLength = 1
let currentString: NSString = (textField.text ?? "") as NSString
let newString: NSString = currentString.replacingCharacters(in: range, with: string) as NSString
return newString.length <= maxLength
}
For Swift 5
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let maxLength = 1
let currentString = (textField.text ?? "") as NSString
let newString = currentString.replacingCharacters(in: range, with: string)
return newString.count <= maxLength
}
Allowing only a specified set of characters to be entered into a given text field
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
var result = true
if mytextField == textField {
if count(string) > 0 {
let disallowedCharacterSet = NSCharacterSet(charactersInString: "0123456789.-").invertedSet
let replacementStringIsLegal = string.rangeOfCharacterFromSet(disallowedCharacterSet) == nil
result = replacementStringIsLegal
}
}
return result
}
How to program an iOS text field that takes only numeric input with a maximum length
Modern Swift
Note that a lot of the example code online is extremely out of date.
Paste the following into any Swift file in your project, example "Handy.swift".
This fixes one of the silliest problems in iOS:
Your text fields now have a .maxLength.
It is completely OK to set that value in storyboard or set in code while the app is running.
// Handy.swift
import UIKit
private var __maxLengths = [UITextField: Int]()
extension UITextField {
#IBInspectable var maxLength: Int {
get {
guard let l = __maxLengths[self] else {
return 150 // (global default-limit. or just, Int.max)
}
return l
}
set {
__maxLengths[self] = newValue
addTarget(self, action: #selector(fix), for: .editingChanged)
}
}
func fix(textField: UITextField) {
let t = textField.text
textField.text = t?.prefix(maxLength).string
}
}
It's that simple.
An even simpler one-off version...
The above fixes all text fields in the whole project.
If you just want one particular text field to simply be limited to say "4", and that's that...
class PinCodeEntry: UITextField {
override func didMoveToSuperview() {
super.didMoveToSuperview()
addTarget(self, action: #selector(fixMe), for: .editingChanged)
}
#objc private func fixMe() { text = text?.prefix(4) }
}
That's all there is to it.
(Here's a similar very useful tip relating to UITextView,
https://stackoverflow.com/a/42333832/294884 )
In Swift 4, simply use:
public func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return range.location < 10
}
The same way Steven Schmatz did it but using Swift 3.0 :
//max Length
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange,
replacementString string: String) -> Bool
{
let maxLength = 4
let currentString: NSString = textField.text! as NSString
let newString: NSString = currentString.replacingCharacters(in: range, with: string) as NSString
return newString.length <= maxLength
}
Simple solution without using a delegate:
TEXT_FIELD.addTarget(self, action: #selector(editingChanged(sender:)), for: .editingChanged)
#objc private func editingChanged(sender: UITextField) {
if let text = sender.text, text.count >= MAX_LENGHT {
sender.text = String(text.dropLast(text.count - MAX_LENGHT))
return
}
}
For Swift 5:
Just write one line to set the maximum character length:
self.textField.maxLength = 10
For more details, see Max character limit of UITextField and allowed characters Swift. (Also credited.)
I think an extension is more handy for this. See the full answer here.
private var maxLengths = [UITextField: Int]()
// 2
extension UITextField {
// 3
#IBInspectable var maxLength: Int {
get {
// 4
guard let length = maxLengths[self] else {
return Int.max
}
return length
}
set {
maxLengths[self] = newValue
// 5
addTarget(
self,
action: #selector(limitLength),
forControlEvents: UIControlEvents.EditingChanged
)
}
}
func limitLength(textField: UITextField) {
// 6
guard let prospectiveText = textField.text
where prospectiveText.characters.count > maxLength else {
return
}
let selection = selectedTextRange
// 7
text = prospectiveText.substringWithRange(
Range<String.Index>(prospectiveText.startIndex ..< prospectiveText.startIndex.advancedBy(maxLength))
)
selectedTextRange = selection
}
}
My Swift 4 version of shouldChangeCharactersIn
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange,
replacementString string: String) -> Bool {
guard let preText = textField.text as NSString?,
preText.replacingCharacters(in: range, with: string).count <= MAX_TEXT_LENGTH else {
return false
}
return true
}
Other solutions posted previously produce a retain cycle due to the textfield map. Besides, the maxLength property should be nullable if not set instead of artificial Int.max constructions; and the target will be set multiple times if maxLength is changed.
Here an updated solution for Swift4 with a weak map to prevent memory leaks and the other fixes
private var maxLengths = NSMapTable<UITextField, NSNumber>(keyOptions: NSPointerFunctions.Options.weakMemory, valueOptions: NSPointerFunctions.Options.strongMemory)
extension UITextField {
var maxLength: Int? {
get {
return maxLengths.object(forKey: self)?.intValue
}
set {
removeTarget(self, action: #selector(limitLength), for: .editingChanged)
if let newValue = newValue {
maxLengths.setObject(NSNumber(value: newValue), forKey: self)
addTarget(self, action: #selector(limitLength), for: .editingChanged)
} else {
maxLengths.removeObject(forKey: self)
}
}
}
#IBInspectable var maxLengthInspectable: Int {
get {
return maxLength ?? Int.max
}
set {
maxLength = newValue
}
}
#objc private func limitLength(_ textField: UITextField) {
guard let maxLength = maxLength, let prospectiveText = textField.text, prospectiveText.count > maxLength else {
return
}
let selection = selectedTextRange
text = String(prospectiveText[..<prospectiveText.index(from: maxLength)])
selectedTextRange = selection
}
}
I give a supplementary answer based on #Frouo. I think his answer is the most beautiful way. Because it's a common control we can reuse. And there isn't any leak problem here.
private var kAssociationKeyMaxLength: Int = 0
extension UITextField {
#IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLength) as? Int {
return length
} else {
return Int.max
}
}
set {
objc_setAssociatedObject(self, &kAssociationKeyMaxLength, newValue, .OBJC_ASSOCIATION_RETAIN)
self.addTarget(self, action: #selector(checkMaxLength), for: .editingChanged)
}
}
// The method is used to cancel the check when using
// the Chinese Pinyin input method.
// Becuase the alphabet also appears in the textfield
// when inputting, we should cancel the check.
func isInputMethod() -> Bool {
if let positionRange = self.markedTextRange {
if let _ = self.position(from: positionRange.start, offset: 0) {
return true
}
}
return false
}
func checkMaxLength(textField: UITextField) {
guard !self.isInputMethod(), let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let maxCharIndex = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
text = prospectiveText.substring(to: maxCharIndex)
selectedTextRange = selection
}
}
Simply just check with the number of characters in the string
Add a delegate to view controller and assign the delegate
class YorsClassName : UITextFieldDelegate {
}
Check the number of characters allowed for the text field
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if textField.text?.count == 1 {
return false
}
return true
}
Note: Here I checked for only characters allowed in textField.
TextField Limit Character After Block the Text in Swift 4
func textField(_ textField: UITextField, shouldChangeCharactersIn range:
NSRange,replacementString string: String) -> Bool
{
if textField == self.txtDescription {
let maxLength = 200
let currentString: NSString = textField.text! as NSString
let newString: NSString = currentString.replacingCharacters(in: range, with: string) as NSString
return newString.length <= maxLength
}
return true
}
I have something to add to Alaeddine's answer:
Your view controller should conform to UITextFieldDelegate
class MyViewController: UIViewController, UITextViewDelegate {
}
Set the delegate of your textfield:
To set the delegate, you can control drag from the textfield to your view controller in the storyboard. I think this is preferable to setting it in code
Implement the method in your view controller:
textField(_:shouldChangeCharactersInRange:replacementString:)
Update for Fattie's answer:
extension UITextField {
// Runtime key
private struct AssociatedKeys {
// Maximum length key
static var maxlength: UInt8 = 0
// Temporary string key
static var tempString: UInt8 = 0
}
// Limit the maximum input length of the textfiled
#IBInspectable var maxLength: Int {
get {
return objc_getAssociatedObject(self, &AssociatedKeys.maxlength) as? Int ?? 0
}
set {
objc_setAssociatedObject(self, &AssociatedKeys.maxlength, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
addTarget(self, action: #selector(handleEditingChanged(textField:)), for: .editingChanged)
}
}
// Temporary string
private var tempString: String? {
get {
return objc_getAssociatedObject(self, &AssociatedKeys.tempString) as? String
}
set {
objc_setAssociatedObject(self, &AssociatedKeys.tempString, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
// When the text changes, process the amount of text in the input
// box so that its length is within the controllable range.
#objc private func handleEditingChanged(textField: UITextField) {
// Special processing for the Chinese input method
guard markedTextRange == nil else { return }
if textField.text?.count == maxLength {
// Set lastQualifiedString where text length == maximum length
tempString = textField.text
} else if textField.text?.count ?? 0 < maxLength {
// Clear lastQualifiedString when text length > maxlength
tempString = nil
}
// Keep the current text range in arcgives
let archivesEditRange: UITextRange?
if textField.text?.count ?? 0 > maxLength {
// If text length > maximum length, remove last range and to move to -1 postion.
let position = textField.position(from: safeTextPosition(selectedTextRange?.start), offset: -1) ?? textField.endOfDocument
archivesEditRange = textField.textRange(from: safeTextPosition(position), to: safeTextPosition(position))
} else {
// Just set current select text range
archivesEditRange = selectedTextRange
}
// Main handle string maximum length
textField.text = tempString ?? String((textField.text ?? "").prefix(maxLength))
// Last configuration edit text range
textField.selectedTextRange = archivesEditRange
}
// Get safe textPosition
private func safeTextPosition(_ optionlTextPosition: UITextPosition?) -> UITextPosition {
/* beginningOfDocument -> The end of the the text document. */
return optionlTextPosition ?? endOfDocument
}
}
Set the delegate of your textfield:
textField.delegate = self
Implement the method in your view controller:
// MARK: Text field delegate
extension ViewController: UITextFieldDelegate {
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return range.location < maxLength (maxLength can be any maximum length you can define)
}
}
Here's a Swift 3.2+ alternative that avoids unnecessary string manipulation. In this case, the maximum length is 10:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let text = textField.text ?? ""
return text.count - range.length + string.count <= 10
}
This answer is for Swift 4 and is pretty straightforward with the ability to let backspace through.
func textField(_ textField: UITextField,
shouldChangeCharactersIn range: NSRange,
replacementString string: String) -> Bool {
return textField.text!.count < 10 || string == ""
}
This is working In Swift 4
Step 1: Set UITextFieldDelegate
class SignUPViewController: UIViewController , UITextFieldDelegate {
#IBOutlet weak var userMobileNoTextFiled: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
Step 2: Set the delegate
userMobileNoTextFiled.delegate = self // Set delegate
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// guard let text = userMobileNoTextFiled.text else { return true }
// let newLength = text.count + string.count - range.length
// return newLength <= 10
// }
Step 3: Call the function
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let maxLength = 10 // Set your need
let currentString: NSString = textField.text! as NSString
let newString: NSString =
currentString.replacingCharacters(in: range, with: string) as NSString
return newString.length <= maxLength
}
}
I use these steps. First set the delegate text field in viewdidload.
override func viewDidLoad() {
super.viewDidLoad()
textfield.delegate = self
}
And then shouldChangeCharactersIn after you include UITextFieldDelegate.
extension viewController: UITextFieldDelegate {
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let newLength = (textField.text?.utf16.count)! + string.utf16.count - range.length
if newLength <= 8 {
return true
}
else {
return false
}
}
}
Just in case, don't forget to guard the range size before applying it to the string. Otherwise, you will get a crash if the user will do this:
Type maximum length text
Insert something (nothing will be inserted due to the length limitation, but iOS doesn't know about it)
Undo insertion (you get a crash, because the range will be greater than the actual string size)
Also, using iOS 13 users can accidentally trigger this by gestures
I suggest you add to your project this
extension String {
func replace(with text: String, in range: NSRange) -> String? {
// NOTE: NSString conversion is necessary to operate in the same symbol steps
// Otherwise, you may not be able to delete an emoji, for example
let current = NSString(string: self)
guard range.location + range.length <= current.length else { return nil }
return current.replacingCharacters(in: range, with: text)
}
}
And use it like this:
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
guard let newText = textView.text.replace(with: text, in: range) else { return false }
return newText.count < maxNumberOfCharacters
// NOTE: You may wanna trim the new text instead,
// so the user will able to shove his long text at least partially
}
Otherwise, you will constantly be getting crashed in your app.
If you have multiple textField that have various length checks on one page I've found an easy and short solution.
class MultipleTextField: UIViewController {
let MAX_LENGTH_TEXTFIELD_A = 10
let MAX_LENGTH_TEXTFIELD_B = 11
lazy var textFieldA: UITextField = {
let textField = UITextField()
textField.tag = MAX_LENGTH_TEXTFIELD_A
textField.delegate = self
return textField
}()
lazy var textFieldB: UITextField = {
let textField = UITextField()
textField.tag = MAX_LENGTH_TEXTFIELD_B
textField.delegate = self
return textField
}()
}
extension MultipleTextField: UITextFieldDelegate {
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return (range.location < textField.tag) && (string.count < textField.tag)
}
}
lazy var textField: UITextField = {
let textField = UITextField()
textField.addTarget(self, #selector(handleOnEditing), for .editingChanged)
return textField
}()
//Set Delegate in ViewDidLoad
textField.delegate = self
#objc func handleOnEditing() {
let text = textField.text ?? ""
let limit = 10
textField.text = String(text.prefix(limit))
}

How do you limit only 1 decimal entry in a UITextField in Swift for iOS8?

I have searched all around for this but still cannot seem to get it to work. I have a simple iOS program with a UITextField that converts Farenheit to Celsius and Kelvin. I am trying to limit only 1 decimal entry in this UITextField. For example 98.9 is ok but 98..9 is not.
This is the function in which I want to limit only 1 decimal. What I would like is if 1 decimal is entered then it will not allow another 1 to be entered but numbers can still be entered after the first decimal of course.
func farenheitButton(sender: AnyObject)
{
var fVal = self.farenheitTextLabel.text
var cVal = self.celsiusTextLabel.text
var kVal = self.kelvinTextLabel.text
if let fVal = self.farenheitTextLabel.text?.toDouble()
{
var fValx = self.farenheitTextLabel.text
var fDoubleValue : Double = NSString (string: fValx).doubleValue
var fToC = (fDoubleValue - 32) * (5/9) //convert Farenheit to Celsius formula
var fToK = ((fDoubleValue - 32) / (1.8000)) + 273.15 //convert Farenheit to Kelvin formula
//create string from value with a format
var afToC : Double = fToC
var bfToC : String = String(format:"%.4f",afToC)
var afToK : Double = fToK
var bfToK : String = String(format:"%.4f",afToK)
celsiusTextLabel.text = bfToC
kelvinTextLabel.text = bfToK
}
}
You can set the UITextField.delegate = self and use the textField(textField: UITextField,shouldChangeCharactersInRange range: NSRange,replacementString string: String) method to do what you want.
The following code will not allow you to enter more than 1 decimal point in the textfield.
func textField(textField: UITextField,shouldChangeCharactersInRange range: NSRange,replacementString string: String) -> Bool
{
let countdots = textField.text.componentsSeparatedByString(".").count - 1
if countdots > 0 && string == "."
{
return false
}
return true
}
You should add UITextFieldDelegate to class ViewController:
class ViewController: UIViewController, UITextFieldDelegate {
...
}
then
If name of your #IBOutlet is textField, (it could looks like:
#IBOutlet weak var textField: UITextField!), then add
override func viewDidLoad() {
super.viewDidLoad()
self.textField.delegate = self
// Do any additional setup after loading the view, typically from a nib.
}
after that you could use:
func textField(textField: UITextField,shouldChangeCharactersInRange range: NSRange,replacementString string: String) -> Bool
{
let countdots = textField.text.componentsSeparatedByString(".").count - 1
if countdots > 0 || textField.text == "."
{
return false
}
return true
}
You can use this subclass of UITextField. It uses the same principle as the answers above, but with a little bit clearer code.
class WMNumberTextField: UITextField, UITextFieldDelegate {
override func awakeFromNib() {
super.awakeFromNib()
delegate = self
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard let text = text else { return false }
let dots = text.characters.filter { $0 == "." }
return dots.count == 0 || string != "."
}
}
Swift 3
func textField(_ textField: UITextField,shouldChangeCharactersIn range: NSRange,replacementString string: String) -> Bool
{
let countdots = (textField.text?.components(separatedBy: (".")).count)! - 1
if (countdots > 0 && string == "."){
return false
}
return true
}
I used below code to limit 1 decimal entry in swift 3.0.
let inverseSet = CharacterSet(charactersIn:".0123456789").inverted
let components = string.components(separatedBy: inverseSet)
let filtered = components.joined(separator: "")
if (textField.text?.contains("."))!, string.contains(".") {
return false
}
return string == filtered
Swift 4: This works !
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard let counter = textField.text?.components(separatedBy: ".") else { return false }
if (counter.count - 1 > 0 && string == ".") { return false }
return true
}
For swift 5 to restrict text field to enter only one (.) decimal.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if string == "." {
let countdots = textField.text!.components(separatedBy: ".").count - 1
if countdots == 0 {
return true
} else {
if countdots > 0 && string == "." {
return false
} else {
return true
}
}
}
return true
}

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