调整图像的高度以适合屏幕（保持宽高比）并使其余部分以编程方式水平滚动

Question

我想让图像的高度适合屏幕的高度，但保持纵横比并使其余部分可水平滚动。您可以查看下面的代码示例。我设法使图像的高度适合屏幕的高度，同时保持这样的纵横比：。

我的最后一个问题是 scrollView 没有在整个水平距离上滚动。只是滚动视图用于滚动较小图像尺寸的距离，所以我也尝试在像这样 How do I auto size a UIScrollView to fit its content 设置 contentView 后重置滚动视图，但不幸的是它不起作用。所以我看不到图像的边缘，但是如果我将滚动视图拉到一侧并保持 "finger" 打开，我可以看到图像。但是我一松开它就会弹回图像的中间部分。

我也看了这个：https://developer.apple.com/library/archive/technotes/tn2154/_index.html 但是我找不到解决问题的方法。

我也已经尝试过计算手动适应屏幕后图像的比例变化，而不是设置滚动视图的内容大小，但这也没有用（就像这个问题的答案： and here: )

代码如下：

import UIKit

class ViewController: UIViewController, UIScrollViewDelegate {
     var scrollView: UIScrollView = {
            let scrollView = UIScrollView()
            scrollView.translatesAutoresizingMaskIntoConstraints = false
            scrollView.backgroundColor = .red
            return scrollView
        }()

        var contentView: UIView = {
            let contentView = UIView()
            contentView.translatesAutoresizingMaskIntoConstraints = false
            return contentView
        }()

        var imageView: UIImageView = {
            let imageView = UIImageView()
            let image = UIImage(named: "Erlebnispark.jpg")
            imageView.image = image
            imageView.backgroundColor = .red
            imageView.translatesAutoresizingMaskIntoConstraints = false
            imageView.contentMode = .scaleAspectFill
            return imageView
        }()

        override func viewDidLoad() {
            super.viewDidLoad()
            self.view.addSubview(scrollView)
            scrollView.addSubview(contentView)
            contentView.addSubview(imageView)
            scrollView.delegate = self
            setupLayout()
        }

        func setupLayout() {
            [
                scrollView.topAnchor.constraint(equalTo: self.view.topAnchor),
                scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
                scrollView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
                scrollView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),

                contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
                contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
                contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
                contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
                //contentView.widthAnchor.constraint(equalTo: scrollView.contentLayoutGuide.widthAnchor),

                contentView.heightAnchor.constraint(equalTo: scrollView.frameLayoutGuide.heightAnchor),
               // contentView.widthAnchor.constraint(equalTo: scrollView.contentLayoutGuide.widthAnchor),

                imageView.topAnchor.constraint(equalTo: contentView.topAnchor),
                imageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
                imageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
                imageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
               // imageView.heightAnchor.constraint(equalTo: contentView.heightAnchor),

                ].forEach {[=10=].isActive = true}
        }
}

也许有人可以帮助我。

Answer 1

只有一些变化...

var imageView: UIImageView = {
    let imageView = UIImageView()
    let image = UIImage(named: "Erlebnispark.jpg")
    imageView.image = image
    imageView.backgroundColor = .red
    imageView.translatesAutoresizingMaskIntoConstraints = false

    // use scaleToFill
    //imageView.contentMode = .scaleAspectFill
    imageView.contentMode = .scaleToFill

    return imageView
}()

setupLayout()中的第一行：

func setupLayout() {
    // add this line
    guard let img = imageView.image else { return }

约束数组的最后一行：

        // add this line
        imageView.widthAnchor.constraint(equalTo: imageView.heightAnchor, multiplier: img.size.width / img.size.height),

        ].forEach {[=12=].isActive = true}

您完成的约束现在告诉图像视图的宽度是它自己的高度，乘数为 img.size.width / img.size.height

其他一切都很好。

调整图像的高度以适合屏幕（保持宽高比）并使其余部分以编程方式水平滚动

Resize height of image to fit screen (keep aspect ratio) and make the rest horizontally scrollable programmatically

scrollview

uiimageview

ios

autolayout

swift