Change UICollectionViewCell size on different device orientations

Question

I am using an UICollectionView with UICollectionViewFlowLayout.

I set the size of each cell through the

collectionView:lay         


        

Answer 1

If you are using autolayout.You just need to invalidate layout in your view controller when rotating and adjust offset in your flow layout subclass.

So, In your view controller -

override func willRotateToInterfaceOrientation(toInterfaceOrientation:     UIInterfaceOrientation, duration: NSTimeInterval) {
    self.galleryCollectionView.collectionViewLayout.invalidateLayout()
}

And in your FlowLayout Subclass

override func prepareLayout() {
    if self.collectionView!.indexPathsForVisibleItems().count > 0{
    var currentIndex : CGFloat!
    currentIndex = CGFloat((self.collectionView!.indexPathsForVisibleItems()[0] as! NSIndexPath).row)
    if let currentVal = currentIndex{
        self.collectionView!.contentOffset = CGPointMake(currentIndex * self.collectionView!.frame.width, self.collectionView!.contentOffset.y);
    }   
    }     
}