有没有办法找出导致这个问题的代码行：

Crashed: com.apple.main-thread
0  UIKit                          0x195694264 __56-[UIPresentationController runTransitionForCurrentState]_block_invoke + 444
1  UIKit                          0x1955d0950 _runAfterCACommitDeferredBlocks + 292
2  UIKit                          0x1955c29ec _cleanUpAfterCAFlushAndRunDeferredBlocks + 528
3  UIKit                          0x195336648 _afterCACommitHandler + 132
4  CoreFoundation                 0x18f1c09a8 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 32
5  CoreFoundation                 0x18f1be630 __CFRunLoopDoObservers + 372
6  CoreFoundation                 0x18f1bea7c __CFRunLoopRun + 956
7  CoreFoundation                 0x18f0eeda4 CFRunLoopRunSpecific + 424
8  GraphicsServices               0x190b58074 GSEventRunModal + 100
9  UIKit                          0x1953a9058 UIApplicationMain + 208
10 FlexConnect                    0x1001b48c8 main (AppDelegate.swift:20)
11 libdyld.dylib                  0x18e0fd59c start + 4

错误本身是：

崩溃：com.apple.main-thread

EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x0000000000000010

编辑：

根据下面的答案,我想知道是否建议使用：

func topMostController() -> UIViewController {
    var topController: UIViewController = UIApplication.sharedApplication().keyWindow!.rootViewController!
    while (topController.presentedViewController != nil) {
        topController = topController.presentedViewController!
    }
    return topController
}

并且总是打电话

let topVC = topMostController().dismiss(animated: true,completion: nil)

在我的应用程序的任何地方,我目前有self.dismiss(动画：真,完成：零)？

这是一个必要的检查或如何确定self.dismiss有问题的地方？

一些样本解雇：

@IBAction func returnToDash(_ sender: UIButton) {
     self.dismiss(animated: true,completion: nil)
}

let pending = UIAlertController(title: "\n\n\n\(title)",message: nil,preferredStyle: .alert)
displayActivityAlertWithCompletion2(ViewController: self,pending: pending){_ in
   Helper_StatusCheck.doSync(_cleanSync: false){
        Prefs.is_Syncing = false
        DispatchQueue.main.async {
            pending.dismiss(animated: true){
                   Toast(text: "Upload sync completed").show()
                   self.dismiss(animated: true,completion: nil)
            }
        }
   }
}

displayActivityAlertWithCompletion2的位置如下：

public func displayActivityAlertWithCompletion2(ViewController: UIViewController,pending: UIAlertController,completionHandler: @escaping ()->())
{
    //let pending = UIAlertController(title: "\n\n\n"+title,preferredStyle: .alert)
    //create an activity indicator
    let indicator = UIActivityIndicatorView(frame: pending.view.bounds)
    indicator.autoresizingMask = [.flexibleWidth,.flexibleHeight]
    indicator.color = UIColor(rgba: Palette.loadingColour)
    //add the activity indicator as a subview of the alert controller's view
    pending.view.addSubview(indicator)
    indicator.isUserInteractionEnabled = false
    // required otherwise if there buttons in the UIAlertController you will not be able to press them
    indicator.startAnimating()



    ViewController.present(pending,animated: true,completion: completionHandler)
}

编辑2：

我的应用程序中的一些示例popover方法：

@IBAction func search(_ sender: UIButton) {
        if let popView = UIStoryboard(name: "AssetCommon",bundle: nil).instantiateViewController(withIdentifier: "searchPop") as? searchPopVC {
            popView.delegate = self
            popView.modalPresentationStyle = .popover;
            popView.popoverPresentationController?.delegate = self
            popView.popoverPresentationController?.barButtonItem = searchButton
            popView.popoverPresentationController?.permittedArrowDirections = .any
            popView.preferredContentSize = CGSize(width: 300,height: 70)
            self.present(popView,completion: nil)
        }
    }

并搜索pop：

class searchPopVC: UIViewController
{
    @IBOutlet weak var searchBar: UISearchBar!

    weak var delegate: SearchPopDelegate?

    override func viewDidLoad()
    {
        super.viewDidLoad()

        searchBar.delegate = self;
    }

    override func didReceiveMemoryWarning()
    {
        super.didReceiveMemoryWarning()
    }

    @IBAction func performSearch(_ sender: UIButton)
    {
        let term = searchBar.text ?? "";
        delegate?.performSearch(with: term)
        self.dismiss(animated: true,completion: nil);
    }
}

extension searchPopVC: UISearchBarDelegate
{
    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
        let term = searchBar.text ?? "";
        delegate?.performSearch(with: term);
        self.dismiss(animated: true,completion: nil)
    }
}