Swift 带有下一页预览的 CollectionView 滑块

Question

我有在每个单元格上显示图像的滑块。我想要做的是在当前页面上显示下一张图片的 10%，然后将它滑到下一页。每张图片都应该在自己的页面中居中（总共 3 张）。

extension OnboardingViewController: UICollectionViewDelegateFlowLayout {

func collectionView(_ collectionView: UICollectionView,
                    layout collectionViewLayout: UICollectionViewLayout,
                    sizeForItemAt indexPath: IndexPath) -> CGSize {
    return CGSize(width: view.frame.width - 200, height: view.frame.height)
}

func collectionView(_ collectionView: UICollectionView,
                    layout collectionViewLayout: UICollectionViewLayout,
                    minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return 0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    let cellWidth : CGFloat = view.frame.width - 200

    let numberOfCells = floor(self.view.frame.size.width / cellWidth)
    let edgeInsets = (self.view.frame.size.width - (numberOfCells * cellWidth)) / (numberOfCells + 1)

    return UIEdgeInsets(top: 15, left: edgeInsets, bottom: 0, right: edgeInsets)
}

}

Answer 1

我所做的是...我插入左边缘。使我的单元格更小，例如初始大小的 0.74，我添加了 2 种方法来在拖动幻灯片时控制我的幻灯片... 然后我使用标志 previewed 将动画添加到我的自定义单元格。所以..我的初始幻灯片总是 previewed 并且大小为 1.0，所有其他幻灯片的大小为 0.9，当我拖动图像时我将 previewed 状态更改为 false 用于所有幻灯片，仅对呈现的幻灯片执行 true。

0.74 是我的单元格大小

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    let cellWidth : CGFloat = view.frame.width * 0.74

    let numberOfCells = floor(self.view.frame.size.width / cellWidth)
    let edgeInsets = (self.view.frame.size.width - (numberOfCells * cellWidth)) / (numberOfCells + 1)

    return UIEdgeInsets(top: 0, left: edgeInsets, bottom: 0, right: edgeInsets)
}

我找到了适合我案例的自定义尺寸

func collectionView(_ collectionView: UICollectionView,
                    layout collectionViewLayout: UICollectionViewLayout,
                    sizeForItemAt indexPath: IndexPath) -> CGSize {
    return CGSize(width: view.frame.width * 0.74, height: view.frame.height)
}

我写了 2 个方法来控制我的幻灯片

func scrollViewWillEndDragging(_ scrollView: UIScrollView,
                               withVelocity velocity: CGPoint,
                               targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    let x = targetContentOffset.pointee.x

    pageControl.currentPage = Int(x / view.frame.width * 0.74)
    let last = viewModel.getNumberOfItems() - 1
    if pageControl.currentPage == last {
        btnStart.isHidden = false
        imbBtnStartBg.isHidden = false
    } else {
        btnStart.isHidden = true
        imbBtnStartBg.isHidden = true
    }

}

func scrollViewWillBeginDecelerating(_ scrollView: UIScrollView) {
    let pageWidth = view.frame.width * 0.74

    let page = floor((collectionView.contentOffset.x - pageWidth / 2) / pageWidth) + 1
    let xOffset: CGFloat = page * pageWidth
    collectionView.setContentOffset(CGPoint(x: xOffset, y: 0.0), animated: true)
    pageControl.currentPage = Int(page)
    if Int(page) == 2{
        btnStart.isHidden = false
        imbBtnStartBg.isHidden = false
    } else {
        btnStart.isHidden = true
        imbBtnStartBg.isHidden = true
    }
    for i in 0..<viewModel.onBoardingModels.count{
        viewModel.onBoardingModels[i].previewed = false
    }
    viewModel.onBoardingModels[Int(page)].previewed = true
    collectionView.reloadData()
}

我还为我的单元格添加了动画[=14=]

UIView.animate(withDuration: 0.5, animations: {
        self.imgv.transform = model.previewed ? CGAffineTransform(scaleX: 1, y: 1) : CGAffineTransform(scaleX: 0.9, y: 0.9)
    })

Swift 带有下一页预览的 CollectionView 滑块

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