ios - UIImageView忽略宽度/高度限制

这是我的课:

class Some: UIView{
override init(frame: CGRect) {
    super.init(frame: frame)
    load()

}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    load()
}

private func load(){
    let someImage = UIImageView()
    someImage.translatesAutoresizingMaskIntoConstraints = false
    someImage.image = UIImage(named: "Test")
    self.addSubview(someImage)
    someImage.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
    someImage.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
    someImage.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5)
    someImage.heightAnchor.constraint(equalTo: self.heightAnchor, multiplier: 0.5)
    }
}

结果如下:



(橙色是我的ViewController的背景)

为什么我的图像会忽略以下行:

someImage.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5)
someImage.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5)

在图像中，它的倍数显然为1.0。实际上，它应该占据屏幕一半的高度和宽度，如乘数(0.5)所示。我究竟做错了什么？

最佳答案

是我还是在最后两个约束中缺少“.isActive = true”？