Question

我正在尝试在alertView之后将popViewController导航到导航堆栈中的上一个View Controller。截至目前，我的程序将不会运行popViewController方法，因为alertView正在阻塞，并引发错误：

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

用户在alertView中单击“确定”后，如何运行popViewController方法？我是否必须设置一个代理，以检测用户点击的时间是否正常？

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，您需要弹出视图控制器。

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)

Answer 2

你可以把＆＃34; popViewControllerAction＆＃34;在这样的警报行动中。

func alertMethod（）{

    var okAlertController = UIAlertController(title: NSLocalizedString("Your title", comment: ""), message: "Your message", preferredStyle: 
    UIAlertControllerStyle.Alert)

    let okAction = UIAlertAction(title: NSLocalizedString("Ok", comment: ""), style: UIAlertActionStyle.Default) { (UIAlertAction) -> Void in
        // your action - navController.popViewControllerAnimated(true)
    }

    let cancelAction = UIAlertAction(title: NSLocalizedString("Cancel", comment: ""), style: UIAlertActionStyle.Default) { (UIAlertAction) -> Void in
        // your action
    }

    }

    saveAlertController.addAction(okAction)
    saveAlertController.addAction(cancelAction)
    self.presentViewController(okAlertController, animated: true, completion: nil)
}

这应该有效，在这种情况下，该方法在用户按下按钮后被调用...

转到导航堆栈中的上一个控制器（Swift）

2 个答案: