将UIimageView添加到UIScrollView

Question

我正在使用带有UIImageView的UIScrollView作为子视图。现在，缩放效果正常，但最初图像尺寸迷失方向，如屏幕截图所示。我该怎么做才能让它成为中心。这是我的代码

@IBOutlet weak var scrollView: UIScrollView!
var imageView = UIImageView();
   override func viewDidLoad() {
    super.viewDidLoad()
    scrollView.delegate = self
    imageView.frame = CGRectMake(16, 16, scrollView.frame.size.width, scrollView.frame.size.height)
    imageView.contentMode = UIViewContentMode.ScaleToFill
    imageView.image = UIImage(named: "abc.png")
    var imagee = UIImage(named: "abc.png")
    let size = imagee?.size
    //imageView.contentMode  = UIViewContentMode.ScaleAspectFit
    imageView.userInteractionEnabled = true
    scrollView.addSubview(imageView)
   scrollView.contentSize = size!
    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 = minScale
    scrollView.maximumZoomScale = 1
    scrollView.zoomScale = minScale

    centerScrollViewContents()
    }
func centerScrollViewContents(){
    let boundsSize = scrollView.bounds.size
    var contentsFrame = imageView.frame

    if contentsFrame.size.width < boundsSize.width{
        contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2
    }else{
        contentsFrame.origin.x = 0
    }

    if contentsFrame.size.height < boundsSize.height {

        contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2
    }else{
        contentsFrame.origin.y = 0
    }

    imageView.frame = contentsFrame

}

func scrollViewDidZoom(scrollView: UIScrollView) {
    centerScrollViewContents()
}

func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
    return imageView
}

以下是我最初获取图片的截图

Answer 1

将centerScrollViewContents方法放入viewWillAppear。