ios - 在 UIView 中居中 UIImageView

Question

所以我有一个名为 currentEventImage 的 UIImageView，它位于 UIView blurryBackGround 中。我目前想要将 UIImageView 置于 UIView 的中心。下面是我当前的代码

//Subviews will be added here
view.addSubview(blurryBackGround)
view.addSubview(currentEventImage)
view.addSubview(currentEventDate)

//Constraints will be added here
_ = blurryBackGround.anchor(top: view.topAnchor, left: view.leftAnchor, bottom: nil, right: view.rightAnchor, paddingTop: 17, paddingLeft: 0, paddingBottom: 0, paddingRight: 0, width: self.view.frame.width, height: 330)
currentEventImage.heightAnchor.constraint(equalToConstant: 330).isActive = true
currentEventImage.topAnchor.constraint(equalTo: blurryBackGround.topAnchor, constant: 5).isActive = true
currentEventImage.center = blurryBackGround.center
blurryBackGround.addSubview(currentEventImage)

知道我该怎么做吗？

currentEventImage.center = blurryBackGround.convert(blurryBackGround.center, from: blurryBackGround.superview)

试过了，还是不行

Answer 1

您可能想尝试以下基于 centerXAnchor 和 centerYAnchor 的解决方案(随意删除对宽度/高度的限制):

import UIKit

class ViewController: UIViewController {
    @IBOutlet var niceIcon:UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        niceIcon.translatesAutoresizingMaskIntoConstraints = false
        niceIcon.heightAnchor.constraint(equalToConstant: 100).isActive = true
        niceIcon.widthAnchor.constraint(equalToConstant: 100).isActive = true
        niceIcon.centerXAnchor.constraint(lessThanOrEqualTo: niceIcon.superview!.centerXAnchor).isActive = true
        niceIcon.centerYAnchor.constraint(lessThanOrEqualTo: niceIcon.superview!.centerYAnchor).isActive = true
    }
}

1. Storyboard示例，原始图标放错位置且没有任何限制。

1. 在模拟器上:

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另一种解决方案(有点冗长)可能是在 leftAnchor、rightAnchor、bottomAnchor 上添加具有相同常量的约束， topAnchor。这个常量代表父 View 和 subview 本身之间的距离。