如何在没有警告的情况下正确添加iOS 11状态栏上的模糊效果？

Question

我曾经使用以下代码在状态栏上添加模糊效果：

// Add blur effect on status bar
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.extraLight)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(blurEffectView)
blurEffectView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
blurEffectView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
blurEffectView.topAnchor.constraint(equalTo: self.topLayoutGuide.topAnchor).isActive = true
blurEffectView.bottomAnchor.constraint(equalTo: self.topLayoutGuide.bottomAnchor).isActive = true

它从Xcode 6或7开始工作，即使对于Xcode 9也是如此。但是，从Xcode 9开始，最后两行开始发出警告：

'topLayoutGuide' was deprecated in iOS 11.0: Use view.safeAreaLayoutGuide.topAnchor instead of topLayoutGuide.bottomAnchor

按照警告，如果我将topLayoutGuide更改为建议值，则结果不正确（所有屏幕均为空白）。

如何在没有警告的情况下正确添加iOS 11状态栏上的模糊效果？

Answer 1

blurEffectView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
blurEffectView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
blurEffectView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
blurEffectView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true