UICollectionViewCell - how to select all items/cells in UIButton action method

Question

I'm trying to select all UICollectionViewCells after a UIButton is tapped.

How do I do this?

Answer 1

Updated for Swift 3

Just Shadow's Answer updated to Swift 3

  for i in 0..<assetCollectionView.numberOfSections {
    for j in 0..<assetCollectionView.numberOfItems(inSection: i) {
        assetCollectionView.selectItem(atIndexPath: IndexPath(row: j, section: i), animated: false, scrollPosition: .none)
    }
}

Answer 2

You can select all cells in the first section through:

for (NSInteger row = 0; row < [self.collectionView numberOfItemsInSection:0]; row++) {
    [self.collectionView selectItemAtIndexPath:[NSIndexPath indexPathForRow:row inSection:0] animated:NO scrollPosition:UICollectionViewScrollPositionNone];
}

If you have more than 1 section, just use another nested for loop to loop through all the sections.