如何禁止用户在NSTextField中键入数字？

Question

How can I forbid users to type numbers in a NSTextField ?

I'm currently using a custom NSFormatter showing a popup after the users typed the value, but how can I prevent the inserting right after typing instead ?

thanks

I've tried this and it almost work.. but if I type a number and then some letters ie "24jdf" the letters are still displayed (even if removed when the field looses focus).

- (BOOL)isPartialStringValid:(NSString *)partialString newEditingString:(NSString **)newString errorDescription:(NSString **)error
//- (BOOL)getObjectValue:(id *)obj forString:(NSString *)string errorDescription:(NSString  **)error
{   

    if ([self numberFromString:partialString] == nil)
        return NO;

    return YES;
}

Answer 1

You'll have to subclass your NSFormatter and override the following method:

-(BOOL)isPartialStringValid:(NSString **)partialStringPtr proposedSelectedRange:(NSRangePointer)proposedSelRangePtr originalString:(NSString *)origString originalSelectedRange:(NSRange)origSelRange errorDescription:(NSString **)error {
   NSString *string = *partialStringPtr;
   NSCharacterSet *numbers = [NSCharacterSet decimalDigitCharacterSet];
   return (NSNotFound == [string rangeOfCharacterFromSet:numbers].location);
}