cocoa textfield 에서 숫자만 입력 하는 방법

http://stackoverflow.com/questions/12161654/restrict-nstextfield-to-only-allow-numbers

@interface OnlyIntegerValueFormatter : NSNumberFormatter

@end

@implementation OnlyIntegerValueFormatter

- (BOOL)isPartialStringValid:(NSString*)partialString newEditingString:(NSString**)newString errorDescription:(NSString**)error
{
    if([partialString length] == 0) {
        return YES;
    }

    NSScanner* scanner = [NSScanner scannerWithString:partialString];

    if(!([scanner scanInt:0] && [scanner isAtEnd])) {
        NSBeep();
        return NO;
    }

    return YES;
}

@end

And then set this formatter to your NSTextField:

OnlyIntegerValueFormatter *formatter = [[[OnlyIntegerValueFormatter alloc] init] autorelease];
[textField setFormatter:formatter];