Restrict NSTextField to only allow numbers
Swift 3 Version
import Foundation
class OnlyIntegerValueFormatter: NumberFormatter {
override func isPartialStringValid(_ partialString: String, newEditingString newString: AutoreleasingUnsafeMutablePointer<NSString?>?, errorDescription error: AutoreleasingUnsafeMutablePointer<NSString?>?) -> Bool {
// Ability to reset your field (otherwise you can't delete the content)
// You can check if the field is empty later
if partialString.isEmpty {
return true
}
// Optional: limit input length
/*
if partialString.characters.count>3 {
return false
}
*/
// Actual check
return Int(partialString) != nil
}
}
Use:
let onlyIntFormatter = OnlyIntegerValueFormatter()
myNsTextField.formatter = onlyIntFormatter
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];