如何创建只允许数字从1到31的文本字段[Objective C]

UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(x, y, width, height)];

textField.keyboardType = UIKeyboardTypeNumberPad;
textField.delegate = self; // 设置代理，用于监听文本输入

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    // 获取用户输入的完整文本
    NSString *updatedText = [textField.text stringByReplacingCharactersInRange:range withString:string];
    
    // 判断是否为有效数字
    NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
    NSNumber *number = [numberFormatter numberFromString:updatedText];
    
    // 判断数字是否在1到31之间
    if (number != nil && number.intValue >= 1 && number.intValue <= 31) {
        return YES; // 允许输入
    } else {
        return NO; // 不允许输入
    }
}