ios - 转到导航堆栈中的上一个 Controller (Swift)

Question

我正在尝试在 alertView 之后将导航堆栈中的前一个 View Controller 弹出 View Controller 。截至目前，我的程序不会运行 popViewController 方法，因为 alertView 挡住了路，并引发了错误:

    UINavigationController 0x17670900 while an existing transition or presentation is occurring; the navigation stack will not be updated.

在用户从 alertView 中单击“确定”后，我如何着手运行 popViewController 方法？我是否必须设置一个委托(delegate)来检测用户何时单击“确定”？

这是我的代码:

    //alertView after Picture saved
    let alertView = UIAlertController(title: "Success!", message: "Record Saved to Database", preferredStyle: .Alert)
    alertView.addAction(UIAlertAction(title: "Ok", style: .Default, handler: nil))

    self.presentViewController(alertView, animated: true, completion: nil)

    //go to previous controller using popViewController, doesnt work, brings up error message
    if let navController = self.navigationController {
        navController.popViewControllerAnimated(true)
    }

Answer 1

当用户从 AlertView 按下 Ok 按钮时，您需要弹出 View Controller 。

let alertView = UIAlertController(title: "Success!", message: "Record Saved to Database", preferredStyle: .Alert)
let OKAction = UIAlertAction(title: "Ok", style: .Default) { (action) in
    // pop here
    if let navController = self.navigationController {
        navController.popViewControllerAnimated(true)
    }
}
alertView.addAction(OKAction)
self.present(alertView, animated: true, completion: nil)