Uppercase characters in UItextfield

Question

I have a question about iOS UIKeyboard.

I have a UITextField and I would to have the keyboard with only uppercase characters.<

Answer 1

Finally I found the way that respects also editing text in the middle of the string in UITextField.

The problem is that if you replace whole text by UITextFiled.text property the actual cursor moves to end of text. So you need to use .replace() method to specify exactly which characters you want to update to upperCase.

Last thing is to return string.isEmpty as return value of function - otherwise you are not allowing deleting of text.

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if let text = textField.text, let textRange = Range(range, in: text) {
        let uppercasedString = string.uppercased()
        let updatedText = text.replacingCharacters(in: textRange, with: uppercasedString)
        if let selectedTextRange = textField.selectedTextRange {
            textField.replace(selectedTextRange, withText: uppercasedString)
            approveButtonState(vin: updatedText)
        }
        return string.isEmpty
    }
    return false
}

Answer 2

One issue I have with some of the above answers is if you try and set textfield.text, you will lose the cursor position. So if a user tries to edit the middle of the text, the cursor will jump to the end.

Here is my Swift solution, still using UITextFieldDelegate:

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

    if textField == textFieldToUppercase {
        if string == "" {
            // User presses backspace
            textField.deleteBackward()
        } else {
            // User presses a key or pastes
            textField.insertText(string.uppercaseString)
        }
        // Do not let specified text range to be changed
        return false
    }

    return true
}

Answer 3

The simplest way would be to implement the editing changed method of the text field and set the textfield's text value to upper case representation of the entered text.

@property (nonatomic, strong) IBOutlet UITextField *yourTextfield

// add target in code or use interface builder
[self.yourTextField addTarget:self 
                       action:@selector(uppercaseTextField)
             forControlEvents:UIControlEventEditingChanged];

- (IBAction)uppercaseTextField:(UITextField*)textField
{
    textField.text = [textField.text uppercaseString];
}

Answer 4

Swift 3 / Swift 4 / Swift 5

Just one line code in ViewDidLoad/ViewDidAppear:

If you simply want to see the characters typed regardless of the UPPER/lower case to all CAPITALS/UPPER CASE paste below code either in ViewDidLoad/ViewDidAppear

self.myTextField.autocapitalizationType = .allCharacters

above line changes all letters into CAPITALS while you type automatically

Answer 5

Maybe it's a bit late for an answer here, but as I have a working solution someone might find it useful.

Well, in the following textfield delegate method, check if the new string contains any lowercase characters. If so, then:

• Append the character that was just typed to the textfield's text.
• Make all the textfield's text uppercased.
• Make sure that false is returned by the method.

Otherwise just return true and let the method work as expected.

Here's its implementation:

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    var returnValue = true
    let lowercaseRange = string.rangeOfCharacter(from: CharacterSet.lowercaseLetters)
    if let _ = lowercaseRange?.isEmpty {
        returnValue = false
    }

    if !returnValue {
        textField.text = (textField.text! + string).uppercased()
    }

    return returnValue
}

The above has worked perfectly for me, and a similar implementation works for textviews too, after making the proper adjustments first of course.

Hope it helps!

Answer 6

You can also use this code.

-(BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range     replacementString:(NSString *)string{

    // Uppercase for string which you need 
    textField.text = [textField.text stringByReplacingCharactersInRange:range 
                                 withString:[string uppercaseString]];

    // return NO because You have already done it in above code
    return NO;
}