PHAssetCollection *collection = (PHAssetCollection *)result;

PHFetchOptions*options = [[PHFetchOptionsalloc]init];

options.predicate = [NSPredicate predicateWithFormat:@"mediaType = %d OR mediaType = %d",PHAssetMediaTypeImage, PHAssetMediaTypeVideo];

?NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO];

//ascending為NO，即為逆序(由現(xiàn)在到過去)， ascending為YES時(shí)即為默認(rèn)排序，由遠(yuǎn)到近

?options.sortDescriptors=@[sort];

?PHFetchResult*assetsFetchResult =[PHAssetfetchAssetsInAssetCollection:collectionoptions:options];