Question

我正在尝试构建一个Instagram的克隆，我决定使用一个返回3个不同单元格的UICollectionViewController，并将滚动方向设置为水平，并将分页设置为true，这样我就可以有三个不同的页面2个垂直单元格我将加载2个其他uicollectionviewcell，它们嵌套1用于dm的feed 1，当用户到达相机时隐藏导航栏我遇到了问题因为Instagram具有为Feed单元格和消息单元格显示的导航栏，但不为相机单元格显示导航栏。下面是我的maincollectionviewcontroller的代码。

import UIKit
import AVFoundation

class MainViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    let cellID = "cellId"
    let messageCellID = "messageCellID"
    let cameraCellID = "cameraCellID"
    var swipeRight = UISwipeGestureRecognizer()

    override func viewDidLoad() {
        super.viewDidLoad()
        let titleImage = UIImageView(image: #imageLiteral(resourceName: "Instagram_logo"))
        titleImage.layer.masksToBounds = true
        self.navigationItem.titleView = titleImage

        setupCollectionView()
        setupSwipeGesture()
       }

//    //Swipe right to get camera
//    func setupSwipeGesture() {
//        swipeRight.direction = .right
//        self.navigationController?.isNavigationBarHidden = true
//        let cameraViewController = ViewController()
//        cameraViewController.transitioningDelegate = self
//        navigationController?.pushViewController(cameraViewController, animated: true)
//    }

    func setupSwipeGesture() {
        print("trying to swipe")
        swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(swiped))
        self.view.addGestureRecognizer(swipeRight)
        swipeRight.direction = .right
    }

    func swiped(){
        print("swipping to get Camera")
        self.navigationController?.isNavigationBarHidden = true
        let cameraViewController = ViewController()
        cameraViewController.transitioningDelegate = self
        navigationController?.pushViewController(cameraViewController, animated: true)

    }


    func setupCollectionView(){

        collectionView?.backgroundColor = .white
        collectionView?.register(MainViewFeedCellCollectionViewCell.self, forCellWithReuseIdentifier: cellID)
        collectionView?.register(MainViewMessagedFeedCell.self, forCellWithReuseIdentifier: messageCellID)
        collectionView?.register(MainViewCameraFeed.self, forCellWithReuseIdentifier: cameraCellID)
        collectionView?.isPagingEnabled = true
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        scrollToMenuIndex(menuIndex: 0)
    }

    func goBackToMainPage(){
        scrollToMenuIndex(menuIndex: 0)
    }

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        if (indexPath.item == 2){
            return collectionView.dequeueReusableCell(withReuseIdentifier: messageCellID, for: indexPath)
        }

        else if (indexPath.item == 0){
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cameraCellID, for: indexPath)
            return cell
        }

        else if (indexPath.item == 1){
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath)
            return cell
        }

        else{
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath)
            return cell
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        print("\(indexPath.row)")
//        if indexPath.row == 0{
//            navigationController?.isNavigationBarHidden = true
//            return CGSize(width: view.frame.width, height:`      view.frame.height )
        //}
        return CGSize(width: view.frame.width, height: view.frame.height - 70)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }

    func scrollToMenuIndex(menuIndex: Int){
        let index = IndexPath(item: menuIndex, section: 0)
        collectionView?.scrollToItem(at: index, at: .centeredHorizontally, animated: true)

    }

}

Answer 1

我为解决类似问题所做的是将UIScrollViewDelegate添加到我的UIViewController中。根据您提供的内容，这是一个解释性答案。由于一次只出现一个UICollectionViewCell，这应该可以解决问题。我不确定这是否是完成它的最佳方式，但它对我有用：

var visibleCurrentCell: IndexPath? {
    for cell in self.collectionView.visibleCells {
        let indexPath = self.collectionView.indexPath(for: cell)
        return indexPath
    }

    return nil
}

func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
    Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(checkIfCameraIsShowing), userInfo: nil, repeats: false)
}

func checkIfCameraIsShowing() {
    if let visibleCurrCell = visibleCurrentCell, let _ = collectionView.cellForItem(at: visibleCurrCell) as? CameraCollectionViewCell {
        self.navigationController?.isNavigationBarHidden = true
    }
}

如何使用不同的单元格大小垂直渲染UICollectionviewcell

1 个答案: