UITextField限制只能輸一個小數點

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
/*
    if (textField == _numberTextfield) {
        if ([string isEqualToString:@"."]) {
            return NO;
        }else{
            return YES;
        }
    }//不能輸入小數點
*/
    if ([textField.text rangeOfString:@"."].location != NSNotFound) {
        if ([string isEqualToString:@"."]) {
            return NO;
        }else{
            NSRange lRange = [textField.text rangeOfString:@"."];
            if (range.location - lRange.location < 3) {
                return YES;
            }else{
                return NO;
            }
            
        }
    }
    
    return YES;
}

實現UITextFieldDelegate代理