ios - 通过代码添加多个 ImageView

Question

我尝试在数组中循环时添加 ImageView ..如下所示:

let v = [1,2,3]
w = self.playgroundimg.frame.width/3 - 48.89/2
h = self.playgroundimg.frame.height/4 - 17

for x in v {
  let imageName3 = "lineupcardbg"
  let image3 = UIImage(named: imageName3)
  let imageView3 = UIImageView(image: image3!)
  imageView3.frame = CGRect(x: w, y: h, width: 48.89, height: 70.15)
  self.playgroundimg.addSubview(imageView3)
  w = w + self.playgroundimg.frame.width/3 - 48.89 - 15
}

这工作正常，但是 ImageView 的尺寸会因设备而异..如下所示:

iPhoneX:

iPhone 7 Plus:

正如你所看到的，中间的那个并不以它下面的那个为中心..如何实现这一点，使中间的在中心，而另外两个在它旁边有一些空间？并在所有尺寸中显示相同？

playgroundimg 约束:

Answer 1

这是一个简单的示例 - 只是为了展示如何使用代码中的约束。

您可以将其粘贴到新的 Playground 页面中并运行它以查看结果。

更改行:

get { return CGSize(width: 400, height: 400) }

调整为不同的尺寸以确保 View 保持居中。

import PlaygroundSupport
import UIKit

class RoundedImageView: UIImageView {

    override init(frame: CGRect) {
        super.init(frame: frame)
        layer.cornerRadius = 8
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

class AlignViewController: UIViewController {

    override public var preferredContentSize: CGSize {
        get { return CGSize(width: 400, height: 400) }
        set { super.preferredContentSize = newValue }
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .green

        var theImageViews = [UIImageView]()

        for _ in 0..<4 {

            let imgView = RoundedImageView(frame: CGRect.zero)
            imgView.translatesAutoresizingMaskIntoConstraints = false
            imgView.backgroundColor = .white

            view.addSubview(imgView)

            // make all views the same size and width
            NSLayoutConstraint.activate([
                imgView.widthAnchor.constraint(equalToConstant: 48.89),
                imgView.heightAnchor.constraint(equalToConstant: 70.15),
                ])

            theImageViews.append(imgView)

        }

        // for easy identification of which views we're referencing
        let leftView = theImageViews[0]
        let centerView = theImageViews[1]
        let rightView = theImageViews[2]
        let bottomView = theImageViews[3]

        NSLayoutConstraint.activate([

            // "center view" will be centered horizontally, and a little above centered vertically
            centerView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            centerView.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -25),

            // left view is aligned to top of center view, and 20-pts to the left
            leftView.topAnchor.constraint(equalTo: centerView.topAnchor),
            leftView.trailingAnchor.constraint(equalTo: centerView.leadingAnchor, constant: -20),

            // right view is aligned to top of center view, and 20-pts to the right
            rightView.topAnchor.constraint(equalTo: centerView.topAnchor),
            rightView.leadingAnchor.constraint(equalTo: centerView.trailingAnchor, constant: 20),

            // bottom view is centerX aligned to center view, and 20-pts below
            bottomView.topAnchor.constraint(equalTo: centerView.bottomAnchor, constant: 20),
            bottomView.centerXAnchor.constraint(equalTo: centerView.centerXAnchor),

            ])

    }

}

let viewController = AlignViewController()

PlaygroundPage.current.liveView = viewController