Restrict NSTextField to only allow numbers

cocoa, nstextfield

Solution

Try to make your own `NSNumberFormatter` subclass and check the input value in `-isPartialStringValid:newEditingString:errorDescription:` method.

@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];

Problem

How do I restrict a `NSTextField` to allow only numbers/integers? I've found questions like this one, but they didn't help!

Original source

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