ios - 在 UIScrollView 中高效加载多个 View

Question

我有一个 UIScrollView，我试图将其用作图像查看器。为此，我启用了分页，并将“幻灯片”添加到每个图像的 View 中，包括 UIImageView 和多个标签和按钮。当我只有几张幻灯片要显示时，这非常有效，但我需要 100 多张幻灯片，而且我遇到了非常糟糕的性能问题。当我呈现 ViewController 并因此设置 ScrollView 时，我得到了 10-15 秒的延迟。显然加载这么多 View 有点太多了。

所以我想知道你们中是否有人知道如何提高效率。

我尝试在之前的 VC 中制作幻灯片数组，然后传递它，而不是当场创建它，这有一点帮助，但不足以让它感觉可以接受，特别是因为更改设备方向将需要我再次设置 ScrollView(因为幻灯片高度/宽度将关闭)。

以下是设置幻灯片并将其呈现在 ScrollView 上的函数:

    func createSlides() -> [Slide] {
    print("creating Slides")

    let Essence = EssenceModel.Essence
    var ImageArray = [Slide]()

    var slide: Slide
    var count = 0


    for img in Essence{
        count += 1

        slide = Bundle.main.loadNibNamed("Slide", owner: self, options: nil)?.first as! Slide
        slide.imageView.image = UIImage(named: img.imageUrl)
        slide.isUserInteractionEnabled = true
        slide.textLabel.text = img.description
        slide.likeButton.imageView?.contentMode = .scaleAspectFit
        slide.hero.id = img.heroID

        slide.tag = count

        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(showOrHide))
        slide.imageView.addGestureRecognizer(tapGesture)
        let dismissGesture = UITapGestureRecognizer(target: self, action: #selector(dismissVC))

        slide.backButton.addGestureRecognizer(dismissGesture)
        slide.backButton.isUserInteractionEnabled = true
        let swipeUp = UISwipeGestureRecognizer(target: self, action: #selector(swipedUp))
        swipeUp.direction = .up
        slide.addGestureRecognizer(swipeUp)

        let swipeDown = UISwipeGestureRecognizer(target: self, action: #selector(swipedDown))
        swipeDown.direction = .down
        slide.addGestureRecognizer(swipeDown)

        let slideRecognizer = UITapGestureRecognizer(target: self, action: #selector(startSlideshow))
        slide.slideButton.addGestureRecognizer(slideRecognizer)
        slide.likeButton.imageView?.contentMode = .scaleAspectFit

        slide.setupZoom()

        ImageArray.append(slide)
    }
    count = 0
    print(ImageArray.count)
    return ImageArray
}


func setupSlideScrollView(slides : [Slide]) {
    scrollView.subviews.forEach { $0.removeFromSuperview() }

        scrollView.frame = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height)
        scrollView.contentSize = CGSize(width: view.frame.width * CGFloat(slides.count), height: view.frame.height)
        scrollView.isPagingEnabled = true

        for i in 0 ..< slides.count {
            slides[i].frame = CGRect(x: view.frame.width * CGFloat(i), y: 0, width: view.frame.width, height: view.frame.height)

            scrollView.addSubview(slides[i])

        }

}

正如我所说，我正在寻找以任何方式提高效率的方法，以便我可以实际使用它。我最好只加载我所在的幻灯片，下一张和上一张，但我不知道如何去做。

这里还有一个屏幕截图，以便您可以看到它的样子。

Answer 1

这样做会更好:

1)添加UICollectionView

2)添加具有restoreID的UITableViewCell

3)向 Controller / View 添加关系

4) 设置水平滚动方向:https://www.screencast.com/t/wmPiwVdY

5)然后创建类似的逻辑:

class ImageCollectionViewVC: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {

    @IBOutlet weak var collectionView: UICollectionView!
    private var images = [Slide]()

    override func viewDidLoad() {
        super.viewDidLoad()
        collectionView.delegate = self
        collectionView.dataSource = self
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return images.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        guard let imageCell = collectionView.dequeueReusableCell(withReuseIdentifier: "ImageSlideCellRestorationID", for: indexPath) as? ImageSlideCell else {
            return ImageSlideCell()
        }
        imageCell.image.image = UIImage(named: images[indexPath.row].imageUrl)
        return imageCell
    }
}


class ImageSlideCell: UICollectionViewCell {
    @IBOutlet weak var image: UIImageView!
}