ios - ScrollView宽高比中的UIImageView不起作用

我在情节提要中定义了一个UIScrollView，并带有一个插座。此滚动视图通过代码（不在情节提要板上）将UIImageView添加到了它。当我运行该应用程序时，图像会被拉长。一旦我触摸以缩放图像，它就会捕捉到适当的纵横比。

这里发生了什么？！

@IBOutlet var scrollView: UIScrollView!

var imageView = UIImageView()
var selectedImage: UIImage!

override func viewDidLoad() {
    super.viewDidLoad()

    scrollView.delegate = self
    imageView.frame = CGRectMake(0, 0, scrollView.frame.size.width, scrollView.frame.size.height)
    imageView.image = selectedImage
    imageView.contentMode = .ScaleAspectFit
    imageView.userInteractionEnabled = true


    scrollView.contentMode = .ScaleAspectFit
    scrollView.addSubview(imageView)

    let scrollViewFrame = scrollView.frame
    let scaleWidth = scrollViewFrame.size.width / scrollView.contentSize.width
    let scaleHeight = scrollViewFrame.size.height / scrollView.contentSize.height
    let minScale = min(scaleHeight, scaleWidth)
    scrollView.minimumZoomScale = 0.3
    scrollView.maximumZoomScale = 1
    scrollView.zoomScale = minScale

    centerScrollViewContents()


    self.closeBtn.layer.cornerRadius = CGRectGetWidth(self.closeBtn.frame)/20.0


}

加载时：


完全移动缩放后：


几乎固定：
我编辑了代码，以在viewWillLayoutSubviews中定义imageView.frame而不是viewDidLoad，如下面的答案所建议。我现在遇到一个新问题-图像无法放大...它使您可以缩放直到松开手指，然后再恢复为原始大小。

这与scrollView.maximumZoomScale不够大有关吗？

更正的代码：

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    imageView.frame = CGRectMake(0, 0, scrollView.frame.size.width, scrollView.frame.size.height)
}
override func viewDidLoad() {
    super.viewDidLoad()

    scrollView.delegate = self
    //imageView.frame = CGRectMake(0, 0, scrollView.frame.size.width, scrollView.frame.size.height)
    imageView.image = selectedImage
    imageView.contentMode = .ScaleAspectFit
    imageView.userInteractionEnabled = true


    scrollView.contentMode = .ScaleAspectFit
    scrollView.addSubview(imageView)

    let scrollViewFrame = scrollView.frame
    let scaleWidth = scrollViewFrame.size.width / scrollView.contentSize.width
    let scaleHeight = scrollViewFrame.size.height / scrollView.contentSize.height
    let minScale = min(scaleHeight, scaleWidth)
    scrollView.minimumZoomScale = 0.3
    scrollView.maximumZoomScale = 2.0
    scrollView.zoomScale = minScale

    centerScrollViewContents()


    self.closeBtn.layer.cornerRadius = CGRectGetWidth(self.closeBtn.frame)/20.0


}

最佳答案

在-viewDidLoad（）方法中设置框架为时过早

如果您将在-viewDidLoad（）中打印您的scrollView.frame，这实际上将返回框架，然后视图将对其子视图进行布局。

因此，您需要在viewWillLayout中对imageView进行约束或重新定义imageView.frame。