解决方案1 我不喜欢它,但它是不依赖于挖掘隐藏子视图(uinavigationbar视图层次结构的内部实现)的最小黑客数量。

首先出现在视图中,我存储“后退”按钮项的备份引用, 然后移除“后退”按钮项(leftbarbuttonem):

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    backButtonBackup = self.navigationItem.leftBarButtonItem
    self.navigationItem.leftBarButtonItem = nil  
}

然后,我恢复back项,但只有在我在viewDidAppear()中调度screen changed事件之后:

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification, nil)
    DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { [weak self] in
        self?.navigationItem.leftBarButtonItem = self?.backButtonBackup
    }
}

解决方案2: 禁用导航栏和视图控制器上的所有辅助功能,直到viewDidAppear()完成:

    self.navigationController.navigationBar.accessibilityElementsHidden = true
    self.view.accessibilityElementsHidden = true

,然后在视图中显示手动将布局元素可访问性事件分派到uinavigationbar的标签子视图:

UIAccessibilityPostNotification( UIAccessibilityLayoutChangedNotification, self.navigationController.navigationBar.subviews[2].subviews[1])   
//  The label buried inside the nav bar.   Not tested on all iOS versions.  
// Alternately you can go digging for the label by checking class types. 
// Then use DispatchAsync, to re-enable accessibility on the view and nav bar again... 

我也不喜欢这种方法。

在任何情况下,viewdid中的dispatchasync延迟似乎都是必需的——我认为这两种解决方案仍然很糟糕。