Set limit to NSTextField

Question

I need to set a character limit for TextFields. I followed this answer and I was able to set a limit. But now when I press enter all characters are wiped out. What went wrong ?

- (BOOL)isPartialStringValid:(NSString *__autoreleasing *)partialStringPtr
       proposedSelectedRange:(NSRangePointer)proposedSelRangePtr
              originalString:(NSString *)origString
       originalSelectedRange:(NSRange)origSelRange
            errorDescription:(NSString *__autoreleasing *)error {
    if ([*partialStringPtr length] > maxLength)
        return NO;
    else
        return YES;
}

- (NSString *)stringForObjectValue:(id)obj {
    return (NSString*) obj;
}

- (BOOL)getObjectValue:(out __autoreleasing id *)obj
             forString:(NSString *)string
      errorDescription:(out NSString *__autoreleasing *)error {
    return YES;
}

- (NSAttributedString *)attributedStringForObjectValue:(id)obj
                                 withDefaultAttributes:(NSDictionary *)attrs {
    return (NSAttributedString*) obj;
}

score 5 · Answer 1 · answered Feb 26 '14 at 13:53

5

How about setting yourself as delegate of the NSTextField an implement this delegate method?

- (void)textDidChange:(NSNotification *)aNotification

There you could check if the text is too long and then cut it if this is the case.

NSTextField *textField = (NSTextField *)[aNotification object];
if ([textField.stringValue length] > maxLength)
{
    textField.stringValue = [textField.stringValue substringWithRange:NSMakeRange(0,maxLength)];
}

answered Feb 26 '14 at 13:53

Michael Knudsen

609
1
6
23

Yes ended up using `controlTextDidChange` But was keen on doing it using NSFormatter class instead which seemed to me like the right thing. – user88975 Feb 26 '14 at 14:32
Check this Thread for NSFormatter (http://stackoverflow.com/questions/827014/how-to-limit-nstextfield-text-length-and-keep-it-always-upper-case) – Jeba Moses May 22 '17 at 07:55

score 2 · Answer 2 · edited Oct 05 '20 at 14:01

Swift 5 in viewDidLoad call the delegate

viewDidload(){
    yourTextFiled.delegate = self
}

extension NSTextField{
    func controlTextDidChange(obj: NSNotification){}
}
extension YourViewController:NSTextFieldDelegate{
    func controlTextDidChange(_ obj: Notification)
    {
        let object = obj.object as! NSTextField
        if object.stringValue.count > yourTextLimit{
        object.stringValue = String(object.stringValue.dropLast())
    }
}

Set limit to NSTextField

2 Answers2

Linked