ScrollView寬高比中的UIImageView不起作用

Question

我在情節提要中定義了一個UIScrollView，並帶有一個插座。 此滾動視圖通過代碼（不在情節提要上）將UIImageView添加到了它。 當我運行該應用程序時，圖像會被拉伸。 一旦我觸摸以縮放圖像，它就會捕捉到適當的縱橫比。

這里發生了什么？！

@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


}

加載后：

完全移動縮放后：

修正的問題：如以下答案所示，我編輯了代碼以在viewWillLayoutSubviews中定義imageView.frame而不是viewDidLoad。 我現在遇到一個新問題-圖像無法放大...它允許您放大圖像，直到松開手指，然后恢復為原始大小。

這與scrollView.maximumZoomScale不夠大有關嗎？

更正的代碼：

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


}

Answer 1

在-viewDidLoad（）方法中設置框架為時過早

如果您將在-viewDidLoad（）中打印您的scrollView.frame，則實際上將返回該框架，然后視圖將對其子視圖進行布局。

因此，您需要在viewWillLayout中對imageView進行約束或重新定義imageView.frame。