swift - 将相册中的照片上传到 UICollectionView

Question

我开始学习 Swift，目前正在参加为 ios 构建应用程序的类(class)。我尝试获取照片并将它们放在 CollectionView 上，它在 Xcode 模拟器上运行良好。然而，我发现当我在 iPhone 上尝试时，collectionView 甚至无法加载。请求图片的代码是这样的。

    let imgManager = PHImageManager.default()

    let requestOptions = PHImageRequestOptions()
    requestOptions.isSynchronous = true
    requestOptions.deliveryMode = .highQualityFormat

请求选项:

    let fetchOptions = PHFetchOptions()
    fetchOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: true)]
    if let fetchResult :PHFetchResult = PHAsset.fetchAssets(with: .image , options: fetchOptions) {

        if fetchResult.countOfAssets(with: PHAssetMediaType.image) > 0 {

            for i in 0..<fetchResult.count{

                imgManager.requestImage(for: fetchResult.object(at: i) as! PHAsset, targetSize: CGSize(width: 200, height: 200), contentMode: .aspectFill, options: requestOptions, resultHandler: {image, Error in
                self.imageArray.append(image!)
                self.PHArray.append(fetchResult.object(at: i))
                    print("Success")
                })

            }

不知何故，在iPhone中，它仍然会请求照片，但不会显示collectionView。我对编码非常陌生，我不确定这是否合适。我们将非常高兴，并欢迎任何真诚的建议。

Answer 1

var 图片:NSMutableArray = NSMutableArray()

func fetchPhotos ()
{
    images = NSMutableArray()
  //  totalImageCountNeeded = 3
    self.fetchPhotoAtIndexFromEnd(0)
}

func fetchPhotoAtIndexFromEnd(index:Int)
{
    let status : PHAuthorizationStatus = PHPhotoLibrary.authorizationStatus()
    if status == PHAuthorizationStatus.Authorized
    {
    let imgManager = PHImageManager.defaultManager()
    let requestOptions = PHImageRequestOptions()
    requestOptions.synchronous = true

    let fetchOptions = PHFetchOptions()
    fetchOptions.sortDescriptors = [NSSortDescriptor(key:"creationDate", ascending: true)]

    if let fetchResult: PHFetchResult = PHAsset.fetchAssetsWithMediaType(PHAssetMediaType.Image, options: fetchOptions)
    {
        if fetchResult.count > 0
        {
            imgManager.requestImageForAsset(fetchResult.objectAtIndex(fetchResult.count - 1 - index) as! PHAsset, targetSize: CGSizeMake(self.img_CollectionL.frame.size.height/3, self.img_CollectionL.frame.size.width/3), contentMode: PHImageContentMode.AspectFill, options: requestOptions, resultHandler: { (image, _) in
                //self.images.addObject(image!)
                if image != nil
                {
                    self.images.addObject(image!)
                }
                if index + 1 < fetchResult.count && self.images.count < 20 //self.totalImageCountNeeded
                {
                    self.fetchPhotoAtIndexFromEnd(index + 1)
                }
                else
                {
                    print("Completed array: \(self.images)")
                }
            })
            self.img_Collection.reloadData()
        }
    }
    }
}

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

func collectionView(_ collectionView: UICollectionView,
                           cellForItemAt indexPath: IndexPath) -> UICollectionViewCell 
{
   let cell  = collectionView.dequeueReusableCellWithReuseIdentifier("cell1", forIndexPath: indexPath)
   let imagess_ : UIImageView = cell.viewWithTag(100) as! UIImageView
   imagess_.image = images [indexPath.row] as? UIImage
        return cell
}