Swift - how to get last taken 3 photos from photo library?

Question

I need to get and show last taken 3 photos from photo library on viewDidload event without any clicks.

After this step, I should get other photos 3 by 3

Answer 1

Here's an elegant solution with efficiency in Swift 4.

In short, we request the latest photo assets once, then convert them into image when needed.

First import Photos Library:

import Photos

Then create a function to fetch the lastest photos taken:

func fetchLatestPhotos(forCount count: Int?) -> PHFetchResult {

    // Create fetch options.
    let options = PHFetchOptions()

    // If count limit is specified.
    if let count = count { options.fetchLimit = count }

    // Add sortDescriptor so the lastest photos will be returned.
    let sortDescriptor = NSSortDescriptor(key: "creationDate", ascending: false)
    options.sortDescriptors = [sortDescriptor]

    // Fetch the photos.
    return PHAsset.fetchAssets(with: .image, options: options)

}

In your case you might want to fetch enough photos at once (for example 50), then store the result somewhere in your view controller:

var latestPhotoAssetsFetched: PHFetchResult? = nil

In viewDidLoad:

self.latestPhotoAssetsFetched = self.fetchLatestPhotos(forCount: 50)

Finally request the image at the right place (for example, a collection view cell):

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

    /*
     ...your code to configure the cell...
     */

    // Get the asset. If nothing, return the cell.
    guard let asset = self.latestPhotoAssetsFetched?[indexPath.item] else {
        return cell
    }
    // Here we bind the asset with the cell.
    cell.representedAssetIdentifier = asset.localIdentifier
    // Request the image.
    PHImageManager.default().requestImage(for: asset,
                                   targetSize: cell.imageView.frame.size,
                                  contentMode: .aspectFill,
                                      options: nil) { (image, _) in
        // By the time the image is returned, the cell may has been recycled.
        // We update the UI only when it is still on the screen.
        if cell.representedAssetIdentifier == asset.localIdentifier {
            cell.imageView.image = image
        }
    }
    return cell
}

Remember to add a property to your cell:

class PhotoCell: UICollectionViewCell {
    var representedAssetIdentifier: String? = nil
}