在swift 4中通过短信推荐朋友

class ViewController: UIViewController, MFMessageComposeViewControllerDelegate {
    //...
    
    func messageComposeViewController(_ controller: MFMessageComposeViewController, didFinishWith result: MessageComposeResult) {
        switch result {
        case .cancelled:
            print("用户取消发送短信")
        case .failed:
            print("发送短信失败")
        case .sent:
            print("短信已发送")
        }
        controller.dismiss(animated: true, completion: nil)
    }
}

func recommendViaSMS() {
    let messageVC = MFMessageComposeViewController()
    messageVC.body = "你好，我正在使用某某APP，非常好用，推荐你也试试！"
    messageVC.recipients = ["+861XXXXXXXXXX"] // 收件人电话号码
    
    messageVC.messageComposeDelegate = self
    self.present(messageVC, animated: true, completion: nil)
}