ios - 尝试在 View 不在窗口层次结构中的 ViewController 上呈现 UIImagePickerController

Question

我遇到了麻烦，之后我从 View Controller 移动到第二个 View Controller ，然后切换回 View Controller 并单击 UI 图像选择器，它没有出现并将我带回到第二个 View Controller 。在调试器上它出现:

Attempt to present on whose view is not in the window hierarchy!

我真的快疯了。将我从第二个 View Controller 带回第一个 View Controller 的代码位于按钮内，如下所示:

 @IBAction func profileButton(_ sender: Any) {
        let webVC = UIStoryboard.init(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController") as! ViewController
        webVC.profileLink = linkProfilo
        self.present(webVC, animated: false, completion: nil)
    }

Answer 1

在第二个 View Controller 中添加此变量:

var firstVC: ViewController?

以及这个设置函数来设置它

setup(firstVC: ViewController) { 
   self.firstVC = firstVC 
} 

在第一个 View Controller 中，当呈现第二个 View Controller 时，通过调用 setup 函数传入对 self(第一个 View Controller )的引用

let secondVC = UIStoryboard.init(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "SecondViewController") as! ViewController
secondVC.setup(firstVC: self)
self.present(secondVC, animated: false, completion: nil)

现在，当在 secondaryVC 中单击按钮时，

guard let first = self.firstVC else {return}
first.profileLink = linkProfilo
self.dismiss(animated: false, completion: nil)