在scrollView中自动布局图像

Question

我以编程方式将图像放入UIScrollview中。 当我在iPhone 8上运行模拟器时，每个图像的宽度完全适合屏幕。 但是，当我在iPhone 8 Plus上运行它时，图像的宽度小于屏幕的宽度。 我认为自动版式有问题。 这背后的可能原因是什么？ 我将以下代码放入ViewDidLoad中。

scrollViewData = [scrollViewDataStruct.init(title: nil, image: #imageLiteral(resourceName: "promotion test 1")), scrollViewDataStruct.init(title: nil, image: #imageLiteral(resourceName: "promotion test 2")), scrollViewDataStruct.init(title: nil, image: #imageLiteral(resourceName: "promotion test 3")), scrollViewDataStruct.init(title: nil, image: #imageLiteral(resourceName: "promotion test 4")), scrollViewDataStruct.init(title: nil, image: #imageLiteral(resourceName: "promotion test 5")), scrollViewDataStruct.init(title: nil, image: #imageLiteral(resourceName: "promotion test 6"))]

scrollView.contentSize.width = self.scrollView.frame.width * CGFloat(scrollViewData.count)

var i = 0
for data in scrollViewData {
    let view = CustomView(frame: CGRect(x: self.scrollView.frame.width * CGFloat(i), y: 0, width: self.scrollView.frame.width, height: self.scrollView.frame.height))
    view.imageView.image = data.image
    self.scrollView.addSubview(view)



    i += 1

我将以下代码分开放置

class CustomView: UIView {

    let imageView: UIImageView = {
        let imageView = UIImageView()
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.backgroundColor = UIColor.clear
        imageView.contentMode = .scaleToFill
        return imageView
    }()

    override init(frame: CGRect) {
        super.init(frame: frame)

        self.addSubview(imageView)
        imageView.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
        imageView.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
        imageView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        imageView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true

    }

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

Answer 1

您的scrollview可能在viewDidLoad中具有错误的框架，因为此时尚未触发布局。 尝试将代码移动到viewWillAppear或viewDidLayoutSubviews（并确保其多次调用），或者在设置框架之前添加一个view.layoutIfNeeded（）调用。

Answer 2

imageView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
imageView.bottomAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true
imageView.leadingAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.leadingAnchor , constant: 0).isActive = true
imageView.trailingAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.trailingAnchor , constant: 0).isActive = true