Objective-C: Numbers only text field? [duplicate]

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {/* for backspace */        if([string length]==0){       return YES;    }/*  limit to only numeric characters  */    NSCharacterSet *myCharSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];    for (int i = 0; i < [string length]; i++) {       unichar c = [string characterAtIndex:i];       if ([myCharSet characterIsMember:c]) {          return YES;      }    }return NO;}

The code is somehow incorrect, should be

/*  limit to only numeric characters  */NSCharacterSet* numberCharSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];for (int i = 0; i < [string length]; ++i){    unichar c = [string characterAtIndex:i];    if (![numberCharSet characterIsMember:c])    {        return NO;    }}return YES;

The following code will allow you to only input numbers as well as limit the amount of characters that can be used.

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {    /*  limit to only numeric characters  */    NSCharacterSet *myCharSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];    for (int i = 0; i < [string length]; i++) {        unichar c = [string characterAtIndex:i];        if ([myCharSet characterIsMember:c]) {            return YES;        }    }    /*  limit the users input to only 9 characters  */    NSUInteger newLength = [customTextField.text length] + [string length] - range.length;    return (newLength > 9) ? NO : YES;}