我看不到添加到UIView的UIView子视图。我可以在视图层次结构中清楚地看到它，但是当应用程序运行时我只是看不到它。

代码：

var magnifyingView: UIView = {
    let view = UIView()
    view.alpha = 1.0
    view.backgroundColor = UIColor.yellow
    return view
}()

guard let cgImage = capturedImage else{return}
    let image = UIImage.init(cgImage: cgImage,scale: 1.0,orientation: UIImage.Orientation.right)
    imageView.image = image
    self.addSubview(imageView)
    bottomSection.addSubview(homeButton)
    bottomSection.addSubview(retakeButton)
    bottomSection.addSubview(continueButton)
    self.addSubview(bottomSection)

    showMagifyingView()
    self.bringSubviewToFront(magnifyingView)

private func showMagifyingView(){
    magnifyingView = UIView()
    magnifyingView.frame = CGRect.init(x: 30,y: 30,width: 200,height: 200)
    self.addSubview(magnifyingView)

    magnifyingView.translatesAutoresizingMaskintoConstraints = false
    magnifyingView.widthAnchor.constraint(equalTo: self.widthAnchor,multiplier: 0.3).isactive = true
    magnifyingView.heightAnchor.constraint(equalTo: self.widthAnchor,multiplier: 0.3).isactive = true
    magnifyingView.topAnchor.constraint(equalTo: self.topAnchor,constant: 30).isactive = true
    magnifyingView.trailingAnchor.constraint(equalTo: self.trailingAnchor,constant: -30).isactive = true

}

查看层次结构（蓝色突出显示的矩形UIview是我在运行时无法在应用程序上看到的内容。即使它存在并且我已经将其放在最前面）