Deleting photo from Photo Library using Photo framework

Question

I am writing a photo album app which can access the photo from the user's photo library, add filter, and delete photo. I used the Photo framework to delete an asset with PHAssetChangeRequest.deleteAssets(assetToDelete). The class of asset here is PHAsset.

// Delete the photo from library    
@IBAction func deleteBtnPressed(_ sender: Any) {
        let assetToDelete = self.asset
        if let assetToDelete = assetToDelete
          {
            PHPhotoLibrary.shared().performChanges({
            PHAssetChangeRequest.deleteAssets(assetToDelete)
          })
        }
      }

But error happen here, "Argument type 'PHAsset' does not conform to expected type 'NSFastEnumeration'".

So I change the type of assetToDelete as Xcode recommended:

PHAssetChangeRequest.deleteAssets(assetToDelete as! NSFastEnumeration)

It still doesn't work, the error is shows that:

Could not cast value of type 'PHAsset' to 'NSFastEnumeration'

Does anyone know how to deal with this? Thanks!

Warren Burton · Accepted Answer · 2019-06-14T13:06:53.167

11

The clue is in the name ‘assets’ plural - the API wants an array or any other collection type that conforms to NSFastEnumeration e.g Set

PHAssetChangeRequest.deleteAssets([assetToDelete] as NSArray)

https://developer.apple.com/documentation/photos/phassetchangerequest/1624062-deleteassets

edited Jun 14 '19 at 13:06

answered Oct 23 '17 at 07:44

Warren Burton

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Declared: `func delete(_ assets: [PHAsset]) {... PHAssetChangeRequest.deleteAssets(assets) ...}`. It gives error `Argument type '[PHAsset]' does not conform to expected type 'NSFastEnumeration'` – Vyachaslav Gerchicov Jun 13 '19 at 09:04
Interesting. Tried casting `as NSArray` ? – Warren Burton Jun 13 '19 at 10:19
yes, it works with casting. But `[assetToDelete]` you mentioned is `swift array`, not `NSArray` – Vyachaslav Gerchicov Jun 13 '19 at 13:15
@VyachaslavGerchicov The compiler "should" bridge the Swift array to NSArray automagically. Are you using Xcode 11? That might be a bug. – Warren Burton Jun 13 '19 at 20:05
With NSArray, as exactly Mr Burton's answer says, works for me. – Markus Aug 27 '19 at 15:21
if not use let arrayToDelete = NSArray(object: lastAsset) – Paresh. P Jan 16 '20 at 05:17
Just an FYI, this bridging no longer works for `PHAsset` arrays in latest Swift – iwasrobbed Jan 22 '20 at 23:28

score 5 · Answer 2 · answered Jan 22 '20 at 23:27

The more correct way would be to fetch from the library first:

let assetIdentifiers = assetsToDeleteFromDevice.map({ $0.localIdentifier })
let assets = PHAsset.fetchAssets(withLocalIdentifiers: assetIdentifiers, options: nil)
PHPhotoLibrary.shared().performChanges({
    PHAssetChangeRequest.deleteAssets(assets)
})

Deleting photo from Photo Library using Photo framework

2 Answers2