在我的应用程序中，使用UIPageViewController来显示完整尺寸的图像，并且在屏幕底部有缩略图CollectionView，每个缩略图都代表UIPageViewController完整尺寸的图像。我的问题是当用户选择不同的缩略图集合视图单元格时如何实现UIpageViewController的分页？ 如果有人知道如何实现此功能，请通过代码或建议或链接帮助我。谢谢
我相信我必须使用UICollectionView的didSelectItemAtIndexPath方法，但不太确定如何最好地做到这一点，请多加帮助。
我的收藏夹查看文件
protocol ThumbnailViewDelegate: class {
func didSelectThumbnail（索引为Int）
} 类ThumbnailView：UIView，UICollectionViewDelegate，UICollectionViewDataSource，UICollectionViewDelegateFlowLayout，PhotoCollectionViewModelPresenter {
weak var delegate: ThumbnailViewDelegate?
var assets: [PHAsset] = []
private let viewModel = PhotoCollectionViewModel()
//private var myViewModel: DetailViewModel!
private let imageDownloader = ImageDownloader(targetSize: CGSize(width: 80, height: 80 ))
//var selectedImage: UIImage?
lazy var thumbnailCollectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
let view = UICollectionView(frame: CGRect.zero, collectionViewLayout: layout)
view.translatesAutoresizingMaskIntoConstraints = false
view.isPagingEnabled = true
view.delegate = self
view.dataSource = self
view.isPrefetchingEnabled = false
view.register(ThumbnailCollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
let cellImageView = ThumbnailCollectionViewCell()
view.addSubview(cellImageView.imageView)
view.backgroundColor = UIColor.white
return view
}()
let imageView: ThumbnailCollectionViewCell = {
let view = ThumbnailCollectionViewCell()
view.contentMode = .scaleAspectFit
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
override init(frame: CGRect) {
super.init(frame: frame)
self.addSubview(thumbnailCollectionView)
thumbnailCollectionView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
thumbnailCollectionView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
thumbnailCollectionView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
thumbnailCollectionView.heightAnchor.constraint(equalToConstant: 100).isActive = true
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
func propagateReload() {
thumbnailCollectionView.reloadData()
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return assets.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath as IndexPath) as! ThumbnailCollectionViewCell
cell.layer.masksToBounds = true
cell.layer.cornerRadius = 8
let image = assets[indexPath.item]
imageDownloader.download(asset: image) { [weak self] (image) in
self?.configureCell(indexPath: indexPath, image: image)
}
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
{
return CGSize(width: 80.0, height: 80.0)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
delegate?.didSelectThumbnail(at: indexPath.item)
}
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
}
func configureCell(indexPath: IndexPath, image: UIImage) {
guard let cell = thumbnailCollectionView.cellForItem(at: indexPath) as? ThumbnailCollectionViewCell else {
return
}
cell.configure(image: image)
}
}
PageViewController文件
MainPageViewController类：UIPageViewController {
var mainImageIndex: Int?
var pageViewModels: [DetailPageViewModel]!
var viewModel: DetailViewModel!
var collectionAssets: [PHAsset] = []
var selectedAsset: UIImage?
private var pendingIndex: Int?
// Collection View
lazy var collectionView: ThumbnailView = {
let view = ThumbnailView()
view.delegate = self
view.assets = self.collectionAssets
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
//MARK: - Create VC
lazy var pageViewControllersArray: [PageViewController] = {
return pageViewModels.map {
return PageViewController(viewModel: $0)
}
}()
var currentIndex:Int {
get {
return pageViewControllersArray.index(of: self.viewControllers!.first! as! PageViewController)!
}
set {
guard newValue >= 0,
newValue < pageViewControllersArray.count else {
return
}
let vc = pageViewControllersArray[newValue]
let direction:UIPageViewController.NavigationDirection = newValue > currentIndex ? .forward : .reverse
self.setViewControllers([vc], direction: direction, animated: true, completion: nil)
}
}
覆盖func viewDidLoad（）{
super.viewDidLoad()
dataSource = self
delegate = self
view.backgroundColor = UIColor.white
setViewControllers([pageViewControllersArray[mainImageIndex ?? 0]], direction: .forward, animated: true, completion: nil)
self.view.addSubview(collectionView)
setupCollectioViewAutoLayout()
}
func setupCollectioViewAutoLayout(){
collectionView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
collectionView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
collectionView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
collectionView.heightAnchor.constraint(equalToConstant: 100).isActive = true
}
func viewWillAppear（）{ super.viewWillAppear（true）
}
}
扩展MainPageViewController：UIPageViewControllerDelegate，UIPageViewControllerDataSource，ThumbnailViewDelegate {
func didSelectThumbnail(at index: Int) {
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
guard let viewController = viewController as? PageViewController else {return nil}
if let index = pageViewControllersArray.index(of: viewController){
if index > 0{
return pageViewControllersArray[index - 1]
}
}
return nil
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
guard let viewController = viewController as? PageViewController else {return nil}
if let index = pageViewControllersArray.index(of: viewController){
if index < pageViewControllersArray.count - 1{
return pageViewControllersArray[index + 1]
}
}
return nil
}
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
return pageViewControllersArray.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
return currentIndex
}
}
答案 0 :(得分：0)
调用select方法时，在整个屏幕上显示另一个页面视图或页面视图控制器。