Question

The Code

if ( !_groups) {
    _groups = [[NSMutableArray alloc] init];
} else {
    [_groups removeAllObjects];
}

if (!_assetsLibrary) {
    _assetsLibrary = [[ALAssetsLibrary alloc] init];
}

ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) {
    if ( group ) {
        DLog(@"group: %@", group);
        [_groups addObject:group];
        [self.tableView reloadData];
    }
};

ALAssetsLibraryAccessFailureBlock failureBlock = ^(NSError *error){
    DLog(@"error: %@", error);
};


NSUInteger groupTypes = ALAssetsGroupAlbum | ALAssetsGroupEvent | ALAssetsGroupFaces;
[_assetsLibrary enumerateGroupsWithTypes:groupTypes usingBlock:listGroupBlock failureBlock:failureBlock];

So the code is straight from WWDC 2010 demo. Session 421.

The Problem

listGroupBlock DLog is never called. And my _groups array is empty;
Technically this block is called 1 time but group parameter is nil.

P.S.
DLog is just pretty NSLog with class name and line in it.

Answer 1

The problem was that on the devices on which I tested, iPad 1, there wasn’t albums/events or faces.

So i’ve changed the groupType from

NSUInteger groupTypes = ALAssetsGroupAlbum | ALAssetsGroupEvent | ALAssetsGroupFaces;

to

NSUInteger groupTypes = ALAssetsGroupLibrary | ALAssetsGroupSavedPhotos | ALAssetsGroupAlbum | ALAssetsGroupEvent | ALAssetsGroupFaces;