Getting photos via PHFetchResult extremely slow with lots of photos - ios

Question

I'm using YangMingShan as a photo picker, and it's exactly what I need, but I'm running into problems when the user has lots of photos.
I've been testing on a phone with 25,000+ photos and 250 albums, and when I present the view controller, the app freezes for about 30 seconds before the collectionView loads.
Here's the problematic bit of code, and I'm trying to figure out if there's a more optimal way to fetch the results.
- (void)fetchCollections
{
NSMutableArray *allAblums = [NSMutableArray array];
PHFetchResult *smartAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
__block __weak void (^weakFetchAlbums)(PHFetchResult *collections);
void (^fetchAlbums)(PHFetchResult *collections);
weakFetchAlbums = fetchAlbums = ^void(PHFetchResult *collections) {
// create fecth options
PHFetchOptions *options = [PHFetchOptions new];
options.predicate = [NSPredicate predicateWithFormat:#"mediaType = %d",PHAssetMediaTypeImage];
options.sortDescriptors = #[[NSSortDescriptor sortDescriptorWithKey:#"creationDate" ascending:NO]];
for (PHCollection *collection in collections) {
if ([collection isKindOfClass:[PHAssetCollection class]]) {
PHAssetCollection *assetCollection = (PHAssetCollection *)collection;
PHFetchResult *assetsFetchResult = [PHAsset fetchAssetsInAssetCollection:assetCollection options:options];
if (assetsFetchResult.count > 0) {
[allAblums addObject:#{#"collection": assetCollection
, #"assets": assetsFetchResult}];
}
}
else if ([collection isKindOfClass:[PHCollectionList class]]) {
// If there are more sub-folders, dig into the collection to fetch the albums
PHCollectionList *collectionList = (PHCollectionList *)collection;
PHFetchResult *fetchResult = [PHCollectionList fetchCollectionsInCollectionList:(PHCollectionList *)collectionList options:nil];
weakFetchAlbums(fetchResult);
}
}
};
PHFetchResult *topLevelUserCollections = [PHCollectionList fetchTopLevelUserCollectionsWithOptions:nil];
fetchAlbums(topLevelUserCollections);
for (PHAssetCollection *collection in smartAlbums) {
PHFetchOptions *options = [PHFetchOptions new];
options.predicate = [NSPredicate predicateWithFormat:#"mediaType = %d",PHAssetMediaTypeImage];
options.sortDescriptors = #[[NSSortDescriptor sortDescriptorWithKey:#"creationDate" ascending:NO]];
PHFetchResult *assetsFetchResult = [PHAsset fetchAssetsInAssetCollection:collection options:options];
if (assetsFetchResult.count > 0) {
// put the "all photos" in the first index
if (collection.assetCollectionSubtype == PHAssetCollectionSubtypeSmartAlbumUserLibrary) {
[allAblums insertObject:#{#"collection": collection
, #"assets": assetsFetchResult} atIndex:0];
}
else {
[allAblums addObject:#{#"collection": collection
, #"assets": assetsFetchResult}];
}
}
}
self.collectionItems = [allAblums copy];
}

Answer 1

Go to YMSPhotoPickerViewController.m and change function.
- (void)refreshPhotoSelection
{
if ([self shouldOrderSelection]) {
PHFetchResult *fetchResult = self.currentCollectionItem[#"assets"];
for (NSInteger i=0; i<self.selectedPhotos.count; i++) {
PHAsset *needReloadAsset = self.selectedPhotos[i];
YMSPhotoCell *cell = (YMSPhotoCell *)[self.photoCollectionView cellForItemAtIndexPath:[NSIndexPath indexPathForItem:[fetchResult indexOfObject:needReloadAsset]+1 inSection:0]];
cell.selectionOrder = i+1;
[self.photoCollectionView selectItemAtIndexPath:[NSIndexPath indexPathForItem:[fetchResult indexOfObject:needReloadAsset]+1 inSection:0] animated:NO scrollPosition:UICollectionViewScrollPositionNone];
}
}
}