swift - 复制/重现UIAlertView模糊效果

我正在尝试在自定义alertView中插入tableview。我需要实现与默认警报相同的样式。从调试视图层次结构中，我几乎复制了样式，但我不知道苹果是如何设置模糊效果的。我的自定义警报视图层次结构here
我试图以编程方式插入模糊视图，但结果太暗、太白或透明度相同

    let blur = UIVisualEffectView(effect: UIBlurEffect(style: .all of them))
    blur.frame = self.alertView.frame
    blur.isUserInteractionEnabled = false
    self.view.insertSubview(blur, at: 1)

最佳答案

它们有几个不同的对话框，但这是一个很好的起点：

/// Composite view of blur + vibrancy + white bg color blending
/// which recreates the Apple alert dialog effect
lazy var dialogView: UIVisualEffectView = {
    let blur = UIBlurEffect(style: .regular)
    let blurView = UIVisualEffectView(effect: blur)
    let vibrancy = UIVibrancyEffect(blurEffect: blur)
    let vibrantView = UIVisualEffectView(effect: blurView.effect)
    vibrantView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    blurView.contentView.addSubview(vibrantView)
    blurView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    blurView.layer.cornerRadius = 20
    blurView.layer.masksToBounds = true
    let blendView = UIView()
    blendView.backgroundColor = .white
    blendView.alpha = 0.5
    blendView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    blurView.contentView.addSubview(blendView)
    return blurView
}()

然后将其添加到视图中并约束w/autolayout。