没有模糊视图效果的UIAlertController操作表 [英] UIAlertController Action Sheet without Blurry View Effect

问题描述

我正在使用UIAlertController进行某些操作.

I'm using UIAlertController for some actions.

但是我不喜欢动作组视图中的模糊视图效果(请参见下面的屏幕截图).

But I'm not a big fan of the Blurry View Effect in the actions group view (see screenshot below).

我正在尝试消除这种模糊效果.我在网上进行了一些研究，但在UIAlertController中找不到任何可以消除这种模糊效果的API.另外，根据他们的Apple文档此处:

I'm trying to remove this blurry effect. I made some research online, and I couldn't find any API in UIAlertController that allows to remove this blurry effect. Also, according to their apple doc here :

UIAlertController类旨在按原样使用，并且不支持子类化.此类的视图层次结构是私有的，不能修改.

The UIAlertController class is intended to be used as-is and does not support subclassing. The view hierarchy for this class is private and must not be modified.

我看到Instagram也消除了这种模糊的视图效果:

I see that Instagram also removes this blurry view effect :

我唯一可以删除它的方法是通过扩展名UIAlertController自己更新视图层次结构.

The only way I could find to remove it is to update the view hierarchy myself via an extension of UIAlertController.

extension UIAlertController {
    @discardableResult private func findAndRemoveBlurEffect(currentView: UIView) -> Bool {
        for childView in currentView.subviews {
            if childView is UIVisualEffectView {
                childView.removeFromSuperview()
                return true
            } else if String(describing: type(of: childView.self)) == "_UIInterfaceActionGroupHeaderScrollView" {
                // One background view is broken, we need to make sure it's white.
                if let brokenBackgroundView = childView.superview {
                    // Set broken brackground view to a darker white
                    brokenBackgroundView.backgroundColor = UIColor.colorRGB(red: 235, green: 235, blue: 235, alpha: 1)
                }
            }
            findAndRemoveBlurEffect(currentView: childView)
        }
        return false
    }
}

let actionSheetController = UIAlertController(title: title, message: nil, preferredStyle: .actionSheet)
actionSheetController.view.tintColor = .lightBlue
actionSheetController.removeBlurryView()

这很好用，它消除了我模糊的视图效果:

This worked fine, it removed my blurry view effect:

我想知道的是...解决方案是实现此目标的唯一方法吗?还是我缺少有关警报控制器外观的信息? 也许有一种更干净的方法来准确地实现该结果?还有其他想法吗?

What I'm wondering... Is my solution the only way to accomplish that? Or there is something that I'm missing about the Alert Controller appearance? Maybe there is a cleaner way to accomplish exactly that result? Any other ideas?

推荐答案

子类的子类比较容易.

It is easier to subclass UIAlertController.

想法是每次调用viewDidLayoutSubviews时都要遍历视图层次结构，删除UIVisualEffectView的效果并更新其backgroundColor:

The idea is to traverse through view hierarchy each time viewDidLayoutSubviews gets called, remove effect for UIVisualEffectView's and update their backgroundColor:

class AlertController: UIAlertController {

    /// Buttons background color.
    var buttonBackgroundColor: UIColor = .darkGray {
        didSet {
            // Invalidate current colors on change.
            view.setNeedsLayout()
        }
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()

        // Traverse view hierarchy.
        view.allViews.forEach {
            // If there was any non-clear background color, update to custom background.
            if let color = $0.backgroundColor, color != .clear {
                $0.backgroundColor = buttonBackgroundColor
            }
            // If view is UIVisualEffectView, remove it's effect and customise color.
            if let visualEffectView = $0 as? UIVisualEffectView {
                visualEffectView.effect = nil
                visualEffectView.backgroundColor = buttonBackgroundColor
            }
        }

        // Update background color of popoverPresentationController (for iPads).
        popoverPresentationController?.backgroundColor = buttonBackgroundColor
    }

}


extension UIView {

    /// All child subviews in view hierarchy plus self.
    fileprivate var allViews: [UIView] {
        var views = [self]
        subviews.forEach {
            views.append(contentsOf: $0.allViews)
        }

        return views
    }

}

用法:

1. 创建警报控制器.
2. 设置按钮的背景色: alertController.buttonBackgroundColor = .darkGray
3. 自定义并显示控制器.

1. Create alert controller.
2. Set buttons background color: alertController.buttonBackgroundColor = .darkGray
3. Customise and present controller.

结果:

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