带有下一页预览的Swift CollectionView滑块

Question

我有一个滑块，可在每个单元格上显示图像。我想做的是在当前页面上显示下一张图像的10％，然后将其滑动到下一页。每个图像应居于自己的页面中心（共3个）。

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...我将左边缘插入。使我的单元格更小，例如初始大小的0.74，当我拖动幻灯片时，我添加了2种方法来控制幻灯片... 然后将动画添加到标记为已预览的自定义单元格中。所以..我的初始幻灯片始终预览，大​​小为1.0，所有其他幻灯片为0.9，当我拖动图片时，我将预览状态更改为假对于所有幻灯片，仅对演示文稿有效。

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)
}

我找到了适合自己情况的尺寸

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

我写了两种控制幻灯片的方法

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()
}

我还将动画添加到我的单元格中

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