swift - 如何更正错误“无法将类型 [NSManagedObject] 的值分配给类型 [String]

Question

我构建了一个使用核心数据并可以发送短信的小应用程序。现在在发送短信部分，它一直告诉我以下一条“messageVC.recipients = items”有错误“无法将类型[NSManagedObject]的值分配给类型[String]。items是一个NSManagedObject数组并存储电话数字。我已经尝试过 messageVC.recipients = items.Stringvalue, messageVC.recipients = items 作为! [String],messageVC.recipients = items.valueforkey["phonenumeb"] 为？字符串，它不能工作。请帮忙。非常感谢。

@IBAction func sendCurrentLocSms(发送者: AnyObject) {

    let messageVC = MFMessageComposeViewController()
    messageVC.body = "My address is " + "\(myAddress.text!) " + ". " + "My GPS is " + "\(myLat.text!)" + "," + "\(myLong.text!)"


    messageVC.subject = "Attention!"


    messageVC.recipients = items

    messageVC.messageComposeDelegate = self

    self.presentViewController(messageVC, animated: false, completion: nil)


}

Answer 1

您需要首先获取一个字符串数组。根据您的实体和 NSManagedObject 子类(如果有)，类似这样的内容应该有效:

messageVC.recipients = items.map { $0.phonenumber }