I have custom keyboard which I added as textfield.inputView. But my shouldChangeCharactersIn at UITextFieldDelegate doesn’t work? Any idea?
You have to implement the call to the delegate method yourself prior to inserting the text into the control.
For example, let’s assume you have some function for handling tap of a button, which calls UIKeyInput method insertText. Just check that the delegate implements the method and that it did not return false:
#objc func didTapButton(_ sender: ...) {
guard let range = target?.selectedRange else { return } // assumes `target` was defined to conform to `UITextInput`, using extension shared below
let string = ...
if let textField = target as? UITextField, textField.delegate?.textField?(textField, shouldChangeCharactersIn: range, replacementString: string) == false {
return
}
if let textView = target as? UITextView, textView.delegate?.textView?(textView, shouldChangeTextIn: range, replacementText: string) == false {
return
}
target?.insertText(string) // assumes `target` was defined to conform to `UIKeyInput`
}
Where:
extension UITextInput {
var selectedRange: NSRange? {
guard let textRange = selectedTextRange else { return nil }
let location = offset(from: beginningOfDocument, to: textRange.start)
let length = offset(from: textRange.start, to: textRange.end)
return NSRange(location: location, length: length)
}
}
Clearly, the details are dependent upon your custom keyboard implementation (the above is based upon https://stackoverflow.com/a/57275689/1271826), but hopefully it illustrates the basic idea.
Related
(Swift)
So the problem is:
My app (which is a kind of calculator) is crashing when the user puts in the textfield things that can't be calculated.
For example, if he types " -4-.", the app won't be able to do the math.
So, a pattern must be followed.
The following characters are allowed: 1234567890.-
The minus sign can only be typed when it is the first character in the textfield and cannot be typed again.
The point can only be typed after a number, and cannot be typed again.
Well you would have to determine:
When the user clicks on a number/digit/character, you would have to do a:
//Goes at top of one of your classes
var decimalCount:Int = 0
//At location of tap for character
if(decimalCount < 1) {
textField.text += "."
decimalCount += 1
}
This ideology could be applied to "-" as well.
Some how i have understood your question. According to my assumption our task is to validate the input for proper math function.Ok here we go.
First of all declare a bool variable at top of your class
var isNonNumericCharactersAllowes = true
At first we need to make our textfield to respond according to user input.So add delegate to text field and add the following delegate method.
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
//1. To make sure that this is applicable to only particular textfield add tag.
if textField.tag == 1 {
let char = string.cStringUsingEncoding(NSUTF8StringEncoding)!
let isBackSpace = strcmp(char, "\\b")
//Helps to react only while typing and not while clearing text
if (isBackSpace != -92) {
let numbersOnly = NSCharacterSet(charactersInString: "1234567890")
let characterSetFromTextField = NSCharacterSet(charactersInString: string)
let Validate:Bool = numbersOnly .isSupersetOfSet(characterSetFromTextField)
if !Validate {
if isNonNumericCharactersAllowes {
isNonNumericCharactersAllowes = false
return true
}
return false
}
isNonNumericCharactersAllowes = true
}
}
return true
}
The above method stops unusual text entry's such as 0..012,--4,4++ etc..
Now while hitting calculate button we need to some validation.Add the following code in IBAction.
#IBAction func calculate(sender: AnyObject) {
let textContent:String!
textContent = textFieldTwo.text
var characterContainer = textContent.characters.map { String($0) }
let numbersOnly = NSCharacterSet(charactersInString: "1234567890")
let lastObjectOfString = NSCharacterSet(charactersInString: characterContainer.last!)
let Validate:Bool = numbersOnly .isSupersetOfSet(lastObjectOfString)
if !Validate {
characterContainer .removeLast()
textFieldTwo.text = characterContainer .joinWithSeparator("")
}
}
This above validation helps in removing things like 30+20+,4+4+, etc.. i.e removes unused operators at the end.
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've been struggling to find how to check the input of a textfield as a user is typing.
if a user types a word, it should change a label and an image according to some defined rules.
my code is working, but I'm always a step behind. (as it reads the content always before the next character is entered.
If it just to check the length I could use countElements(textfield) + 1, but I want it to also show that a user cannot use certain characters as they are typing, therefore that would not work for checking undesired characters.
I am assuming the function I am using is not the right one "shouldChangeCharacters". So I am a bit lost as to what to use. Is there a way to read a println or NSLog command to return to an outlet?
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let passwordcheck = UserPasswordTextField.text
if UserPasswordTextField.isFirstResponder() {
if isValidPassword(passwordcheck) {
PWimg.image = UIImage(named: "passwordapprovedicon")
} else if passwordcheck.isEmpty {
PWimg.image = UIImage(named: "passwordiconwrong")
} else {
PWimg.image = UIImage(named: "passwordiconwrong")
}
}
func isValidPassword(testStr2:String) -> Bool {
println("validate password: \(testStr2)")
let passwordRegEx = "[A-Z0-9a-z._%+-:/><#]{6,30}"
if let passwordTest = NSPredicate(format: "SELF MATCHES %#", passwordRegEx) {
return passwordTest.evaluateWithObject(testStr2)
}
return false
Listen for UIControlEventEditingChanged events from the text field. Register for them either with
the Interface Builder: drag from the text field to the file, and select the action type "Editing Changed"
the following code:
override func viewDidLoad() {
super.viewDidLoad()
// ...
textField.addTarget(self, action:"edited", forControlEvents:UIControlEvents.EditingChanged)
}
func edited() {
println("Edited \(textField.text)")
}
Updated for swift 3:
override func viewDidLoad() {
super.viewDidLoad()
//...
textField.addTarget(self, action: #selector(textFieldDidChange), for:.editingChanged)
}
func textFieldDidChange(){
print(textField.text)
}
Updated for swift 4.2: just add #objc to func textFieldDidChange()
override func viewDidLoad()
{
super.viewDidLoad()
textField.addTarget(self,
action : #selector(textFieldDidChange),
for : .editingChanged)
}
#objc func textFieldDidChange()
{ print(textField.text ?? "Doh!") }
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
}