当弹出窗口在屏幕上时，UIBarButtonItem 未脱色/禁用

Question

我的导航控制器上有两个UIBarButtonItems：

    segmentControl = UISegmentedControl(items: ["Up", "Down"])
    infoItem = UIBarButtonItem(image: infoImage,
                               style: .plain, 
                               target: self,
                               action: #selector(infoAction))
    navigationItem.rightBarButtonItems = [infoItem, UIBarButtonItem(customView: segmentControl)]

点击infoItem时我会这样做：

@objc func infoAction()
{
    let popoverContentController = InfoViewController()

    popoverContentController.preferredContentSize = CGSize(width: 300, height: 300)
    popoverContentController.modalPresentationStyle = .popover
    popoverContentController.popoverPresentationController?.delegate = self
    popoverContentController.popoverPresentationController?.passthroughViews = nil

    self.present(popoverContentController, animated: true, completion: nil)
}

然后调用UIPopoverPresentationControllerDelegate 函数：

func prepareForPopoverPresentation(_ popoverPresentationController: UIPopoverPresentationController)
{
    popoverPresentationController.permittedArrowDirections = .any
    popoverPresentationController.barButtonItem = infoItem
    popoverPresentationController.passthroughViews = nil
}

func adaptivePresentationStyle(for controller: UIPresentationController,
                               traitCollection: UITraitCollection) -> UIModalPresentationStyle
{
    return .none
}

即使我将passthroughViews 设置为nil 两次，UISegmentedControl 也不会脱色，并且在弹出框出现在屏幕上时仍然可以点击。

如果显示任何其他弹出框，UISegmentedControl 的行为正常：已脱色且不可点击。

我在这里错过了什么？

Answer 1

查看您的代码，一切似乎都很好。操作系统似乎有错误。

我已经找到了一个快速解决方案，除非他们在下一个 iOS 版本中检查并修复它。

1. 定义 barButtonItems 和一个变量以将现有的色调颜色全局保存在您的 ViewController 中。

   var infoItem: UIBarButtonItem!
   var segmentItem: UIBarButtonItem!
   var savedTintColour: UIColor? = nil
   

2. 在你的ViewDidLoad() 中初始化它们

   segmentedControl = UISegmentedControl(items: ["Up", "Down"])
   infoItem = UIBarButtonItem(image: UIImage(named: "setting_mobile"),
                              style: .plain,
                              target: self,
                              action: #selector(infoAction))
   segmentItem = UIBarButtonItem(customView: segmentedControl)
   navigationItem.rightBarButtonItems = [infoItem, segmentItem]
   

3. InfoAction 的代码将保持不变。

   @objc func infoAction() {
       let popoverContentController = InfoViewController()
   
       popoverContentController.preferredContentSize = CGSize(width: 300, height: 300)
       popoverContentController.modalPresentationStyle = .popover
       popoverContentController.popoverPresentationController?.delegate = self
       popoverContentController.popoverPresentationController?.passthroughViews = nil
   
       self.present(popoverContentController, animated: true, completion: nil)
   }
   

4. 实现委托方法 prepareForPopoverPresentation 并将 tint color 设置为 darkGray 并将之前可用的 tintColour 保存到一个变量中，以便我们可以在启用时重用它。

   func prepareForPopoverPresentation(_ popoverPresentationController: UIPopoverPresentationController) {
   popoverPresentationController.permittedArrowDirections = .any
   popoverPresentationController.barButtonItem = infoItem
   popoverPresentationController.passthroughViews = nil
   
   self.segmentItem.isEnabled = false
   if savedTintColour == nil {
       savedTintColour = self.segmentedControl.tintColor
   }
   self.segmentedControl.tintColor = .darkGray
   }
   

5. 实现一个委托方法popoverPresentationControllerDidDismissPopover，重置segmentControl的颜色并启用segmentedItem。

   func popoverPresentationControllerDidDismissPopover(_ popoverPresentationController: UIPopoverPresentationController) {
   self.segmentItem.isEnabled = true
   self.segmentedControl.tintColor = savedTintColour!
   }
   

希望对你有帮助。

Answer 2

正如Bhavin Kansagara 所建议的那样，模仿iOS 行为是一种有效的解决方法。他的回答很接近，但遗漏了一些细节：

• popoverPresentationControllerDidDismissPopover 调用太晚导致分段控件在所有其他 UI 元素之后再次变为蓝色。需要改用popoverPresentationControllerShouldDismissPopover。
• 颜色变化需要动画，就像在 iOS 中一样。
• segmentedControl 的isEnabled 也必须保存。
• 在禁用状态下处理较浅的颜色。

这是我所做的，希望有更好的解决方案：

private var segmentedControlTintColor: UIColor?
private var segmentedControlIsEnabled: Bool = true

// Due to, what seems to be, an iOS issue, the segmented control is not decolorized when the info popover is
// on screen.  The two functions below mimick iOS behavior until a better solution is found.
func decolorizeSegmentedControl()
{
    segmentedControlIsEnabled = segmentedControl.isEnabled
    segmentedControl.isEnabled = false
    segmentedControlTintColor = segmentedControl.tintColor
    UIView.animate(withDuration: 0.333)
    {
        self.segmentedControl.tintColor = self.segmentedControlIsEnabled ? .darkGray : .lightGray
    }
}

func colorizeSegmentedControl()
{
    segmentedControl.isEnabled = segmentedControlIsEnabled
    UIView.animate(withDuration: 0.333)
    {
        self.segmentedControl.tintColor = self.segmentedControlTintColor
    }
}

func prepareForPopoverPresentation(_ popoverPresentationController: UIPopoverPresentationController)
{
    popoverPresentationController.permittedArrowDirections = .any
    popoverPresentationController.barButtonItem = infoItem

    decolorizeSegmentedControl()
}

func popoverPresentationControllerShouldDismissPopover(_ popoverPresentationController: UIPopoverPresentationController) -> Bool
{
    colorizeSegmentedControl()

    return true
}