iOS 13:违反线程:预期主线程 [英] iOS 13: threading violation: expected the main thread

问题描述

尝试仅为 iOS 13 用户隐藏视图控制器的导航栏时，该应用程序已崩溃.

The app is being crashed when trying to hide the navigation bar for a viewcontroller only for iOS 13 users.

• 我在Fabric的Crashlytics上崩溃，标题如下，

致命异常:NSInternalInconsistencyException

Fatal Exception: NSInternalInconsistencyException

线程违规:应该是主线程

threading violation: expected the main thread

• 该应用程序在此viewWillAppear方法行上崩溃了，

    self.navigationController?.isNavigationBarHidden = true

• 要隐藏UIViewController的viewWillAppear方法上的导航栏，我正在使用以下代码，

    override func viewWillAppear(_ animated: Bool) {
        self.navigationController?.isNavigationBarHidden = true
        super.viewWillAppear(animated)
    }

• 要在UIViewController的viewWillDisappear方法上显示导航栏，我正在使用以下代码，

    override func viewWillDisappear(_ animated: Bool) {
        self.navigationController?.isNavigationBarHidden = false
        super.viewWillDisappear(animated)
    }

推荐答案

执行以下操作

  DispatchQueue.main.async {
    self.navigationController?.isNavigationBarHidden = false
  }

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