ios - 将数据从 View Controller 传递到 tabbarviewcontroller

Question

我正在从一个 View Controller 切换到一个 tabbarcontroller，我想传递数据。我想将“sendAuthor”传递给 tabbarcontroller 的第一个 View Controller 。

 override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
   if segue.identifier == "FirstVC" {

  let vc = (segue.destination as? UITabBarController)?.viewControllers?.first as? CommentProfileViewController

    vc?.sendAuthor = sendAuthor!
    vc?.Username.text = sendAuthor!

        print(sendAuthor!)
    }



    }

为了确保我得到正确的东西，我包含了一个打印语句 print(sendAuthor!) 并且我得到了正确的打印语句。我还在目标 View Controller 中包含了一个打印语句，但打印语句返回 nil

var sendAuthor: String?

override func viewDidLoad() {
        super.viewDidLoad()
print(self.sendAuthor)

}

Answer 1

您的 VC 嵌入在 UINavigationController 中。您还需要考虑到这一点:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
   if segue.identifier == "FirstVC" {
       guard let tabbar = segue.destination as? UITabBarController,
             let navcon = tabbar.viewControllers?.first as? UINavigationController,
             let vc = navcon.topViewController as? CommentProfileViewController
             else { return }

       vc.sendAuthor = sendAuthor!
       vc.Username.text = sendAuthor!

       print(sendAuthor!)
    }
}