Loading videos with predicates — iOS — Swift

Here is an article for those who are trying to load videos with predicates in Photos Kit.

First create a global variable that can take fetch results

var assetsFetchResult = PHFetchResult<PHAsset>()

Then we create variable from PHFetchOptions(). This will contain all our predicates and sortDescriptors.

let option = PHFetchOptions()

I was working on an application that loads videos by date. So I will use that as the predicate and sort by creationDate.

Here is the code that I used to setup my PHFetchOptions()

currentDate is a global variable of Date()

let option = PHFetchOptions()
var calendar = Calendar.current
calendar.timeZone = TimeZone.current
let predicate = NSPredicate(format: "creationDate > %@ AND creationDate < %@ AND mediaType == %i", currentDate.startOfDay as NSDate, currentDate.endOfDay as NSDate, PHAssetMediaType.video.rawValue)
option.predicate = predicate
let sort = NSSortDescriptor(key: "creationDate", ascending: true)
option.sortDescriptors = [sort]

See the predicate options you have..

PHFetchOptions - Photos | Apple Developer Documentation

😯 If you wonder how I got the currentDate.startOfDay, Don’t worry… I wrote a simple extension for that and here it is…

extension Date {
  var startOfDay : Date {
    let calendar = Calendar.current
    let unitFlags = Set<Calendar.Component>([.year, .month, .day])
    let components = calendar.dateComponents(unitFlags, from: self)
    return calendar.date(from: components)!
  }
}

Then we are good to go.. Now we fetch videos with PHAssetCollection that uses to group videos.

let videoSmartAlbumsFetchResult = PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .smartAlbumVideos, options: nil)

It returns PHAssetCollection with smartAlbum results. Then we grab that collection and derive the data out of it from the code below.

if videoSmartAlbumsFetchResult.count > 0 {
  let videoSmartAlbum = videoSmartAlbumsFetchResult[0]
  assetsFetchResult = PHAsset.fetchAssets(in: videoSmartAlbum, options: option)
  PHPhotoLibrary.shared().register(self)
}

You might wonder what does this line do… 😳

PHPhotoLibrary.shared().register(self)

Wanna know about it? please read this article…

Observing photo album changes — iOS — Swift

Now let’s look at how you can read the videos that are in assetsFetchResult .

It’s just a for loop to loop trough the assetsFetchResult array.

for i in 0..<assetsFetchResult.count {
 let asset = self.assetsFetchResult[i]
}

Huh.. Pretty simple.. isn’t it..

Now we have our asset from PHAsset . Fell free to do anything with it you like..

So the complete method is here..

var assetsFetchResult = PHFetchResult<PHAsset>()
private func loadVideos() {
 let option = PHFetchOptions()
 var calendar = Calendar.current
 calendar.timeZone = TimeZone.current
 let predicate = NSPredicate(format: "creationDate > %@ AND creationDate < %@ AND mediaType == %i", currentDate.startOfDay as NSDate, currentDate.endOfDay as NSDate, PHAssetMediaType.video.rawValue)
 option.predicate = predicate
 let sort = NSSortDescriptor(key: "creationDate", ascending: true)
 option.sortDescriptors = [sort]
 let videoSmartAlbumsFetchResult = PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .smartAlbumVideos, options: nil)
 if videoSmartAlbumsFetchResult.count > 0 {
  let videoSmartAlbum = videoSmartAlbumsFetchResult[0]
  assetsFetchResult = PHAsset.fetchAssets(in: videoSmartAlbum, options: option)
  PHPhotoLibrary.shared().register(self)
 }
}

Enjoy. 😊