UICollection视频库

Question

我正在尝试对一个人的视频库进行UICollection;并且应用程序在此行崩溃：错误本身是“访问不良”

self.videoArray.append(video!)

以下是完整代码：

import UIKit
import Photos

class uploadVideoVC: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {

    var imageArray = [UIImage]()

    var videoArray = [AVPlayerItem]()

    func grabPhotos() {
        let imgManger = PHImageManager.default()

        let requestOptions = PHImageRequestOptions()

        requestOptions.isSynchronous = true
        requestOptions.deliveryMode = .highQualityFormat


        let videoRequests = PHVideoRequestOptions()
        videoRequests.deliveryMode = .highQualityFormat

        let fetchOptions = PHFetchOptions()
        fetchOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)] //can add multiple sorts by a comma

        if let fetchResult : PHFetchResult = PHAsset.fetchAssets(with: .video, options: fetchOptions) {

            if fetchResult.count > 0 {

                for i in 0..<fetchResult.count {

                   /** imgManger.requestImage(for: fetchResult.object(at: i), targetSize: CGSize(width: 200, height:200), contentMode: .aspectFill, options: requestOptions, resultHandler: {

                        image, error in

                        self.imageArray.append(image!)

                    })**/

                   imgManger.requestPlayerItem(forVideo: fetchResult.object(at: i), options: videoRequests, resultHandler: { video, error in
                     self.videoArray.append(video!)
                     })
                }

            } else {
                print("no photos mang")

                //i still think we need to reload the data?

            }

        }
    }


    let topBar = UIView()
    let videoCollectionView = UIView()

    override func viewDidLoad() {
        super.viewDidLoad()
        grabPhotos()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(true)
        self.view.backgroundColor = UIColor.red
        let flowLayout = UICollectionViewFlowLayout()

        let collectionView = UICollectionView(frame: self.view.bounds, collectionViewLayout: flowLayout)
        collectionView.register(VideoSelectionCVCell.self, forCellWithReuseIdentifier: cellId)

        collectionView.delegate = self
        collectionView.dataSource = self
        collectionView.backgroundColor = UIColor.cyan

        self.view.addSubview(collectionView)        // Do any additional setup after loading the view.
        self.navigationController?.isNavigationBarHidden = true;

        topBar.frame = (frame: CGRect(x: self.view.frame.size.width * 0, y: self.view.frame.size.height * 0, width:self.view.frame.size.width, height: self.view.frame.size.height / 15))
        topBar.backgroundColor = UIColor.blue.withAlphaComponent(0)

        // topBar.layer.cornerRadius = self.view.frame.width*0.04

        self.view.addSubview(topBar)

        videoCollectionView.frame = (frame: CGRect(x: self.view.frame.size.width * 0, y: self.view.frame.size.height / 15, width:self.view.frame.size.width, height: self.view.frame.size.height))
        videoCollectionView.backgroundColor = UIColor.red

        self.view.addSubview(videoCollectionView)

        videoCollectionView.addSubview(collectionView)


    }



    var numOfCol : Int = 2


    var cellId = "Cell"

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



    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
    {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! VideoSelectionCVCell

      //  cell.uploadedFile.image = imageArray[indexPath.row]

        //cell.uploadedFile.image = videoArray[indexPath.row] as! UIImage
        cell.backgroundColor = UIColor.purple
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        let width = (collectionView.bounds.width) / 2
        let height = (collectionView.bounds.height)/4 // = 25% of the screen



        return CGSize(width:width, height:height)
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 1
    }



    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {

        return 0.0
    }

    override var prefersStatusBarHidden: Bool {
        get {
            return true
        }
    }

}

Answer 1

不要强力打开选项。这就是让和守护关键字的用途。用以下内容替换崩溃线：

guard let video = video, error == nil else {
    print("something bad happened")
    return
}

self.videoArray.append(video)