Fetch Album with local Identifier using Photos Framework

Question

I am keeping track from which album the user has selected a photo and passing it as a string (albumName) to the next VC.

I want to fetch only the photos in that album for further selection and processing.

this is what I thought would do the trick but I must be missing something:

-(void) fetchImages{
    self.assets = [[PHFetchResult alloc]init];
        NSLog(@"Album Name:%@",self.albumName);

    if (self.fromAlbum) {


        PHFetchResult *userAlbums = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[self.albumName]    options:nil];
        PHAssetCollection *collection = userAlbums[0];

        PHFetchOptions *onlyImagesOptions = [PHFetchOptions new];
        onlyImagesOptions.predicate = [NSPredicate predicateWithFormat:@"mediaType = %i", PHAssetMediaTypeImage];

        NSLog(@"Collection:%@", collection.localIdentifier);

        self.assets = [PHAsset fetchAssetsInAssetCollection:collection options:onlyImagesOptions];

.....

when i log the collection.localIdentifier i get null so no collection/album is fetched.

What am I missing/messing up?

Thanks

Answer 1

If you trying fetch collection by Album Name use code below

    PHFetchOptions *fetchOptions = [[PHFetchOptions alloc] init];
    fetchOptions.predicate = [NSPredicate predicateWithFormat:@"title = %@", albumNamed];
    PHFetchResult *fetchResult = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
                                                           subtype:PHAssetCollectionSubtypeAny
                                                           options:fetchOptions];

PHAssetCollection *collection = fetchResult.firstObject;

Answer 2

Album name is not a local identifier that's why the method fetchAssetCollectionsWithLocalIdentifiers returns nil .
Also names of albums are not unique, and it's possible to create multiple albums with the same name, so in this case your app may not work properly.
I guess that you have previously fetched asset collections and kept its' localizedTitle in string albumName .
I would recommend you to keep and use localIdentifier of assetcollection instead of localizedTitle and pass it to VC. Then you'll be able to easily fetch assets by using that identifier.

 //Assume we have previously done this to fetch album name and identifier
 PHFetchResult * myFirstFetchResult = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAny options:nil];
 PHAssetCollection * myFirstAssetCollection = myFirstFetchResult.firstObject;
 NSString * albumName = myFirstAssetCollection.localizedTitle;
 NSString * albumIdentifier = myFirstAssetCollection.localIdentifier;    //<-Add this...

 //Pass albumIdentifier to VC...

 //Inside your 'fetchImages' method use this to get assetcollection from passed albumIdentifier
 PHFetchResult *userAlbums = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[self.albumIdentifier] options:nil];
 PHAssetCollection *collection = userAlbums.firstObject;
 //Now you have successfully passed and got asset collection and you can use