How can you tell a device has rotated so you can reload a UICollectionView

Question

I want to invalidateLayout() of the custom UICollectionView when the bounds are changed. I know that I can call this method from the controller using viewWillLayoutSubviews(). But since I want to make this custom UICollectionView as a framework, I want to implement the function without being dependent to the controller.

If I try to invalidateLayout() inside override open func layoutSubviews() then I get an infinite loop.

What is the best way to implement what I want with the constraints give?

you mean when you rotate device you want to update layout? – Tushar Sharma Jul 30 '17 at 05:13 — Tushar Sharma, Jul 30 '17 at 05:13
@TusharSharma you are a mind reader !! – Ham Dong Kyun Jul 30 '17 at 05:39 — Ham Dong Kyun, Jul 30 '17 at 05:39

Tushar Sharma · Answer 1 · 2017-07-30T05:59:25.913

0

View Controllers have this method -:

override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
        collectionView.collectionViewLayout.invalidateLayout()
    }

edited Jul 30 '17 at 05:59

answered Jul 30 '17 at 05:47

Tushar Sharma

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Are you sure it is the UICollectionView that has this method? Can you give me the link to the Apple Developer Documentation? I couldn't find it – Ham Dong Kyun Jul 30 '17 at 05:56
@Ham Dong Kyun its a view controller method sorry for mistake . You can just type it out and you will get one. – Tushar Sharma Jul 30 '17 at 06:00
Sorry, but I explicitly explained that I do not want to link it to the controller. – Ham Dong Kyun Jul 30 '17 at 06:00
@HamDongKyun what you meant by link to controller? Please explain . – Tushar Sharma Jul 30 '17 at 06:02
I want the code to be in the UICollectionView subclass and not linked to any UIViewControllers. – Ham Dong Kyun Jul 30 '17 at 06:03
@Ham Dong Kyun I am not getting what are you trying to achieve with that, but this is the only good way you can determine rotation and update layout without any burden. – Tushar Sharma Jul 30 '17 at 06:05
I want to make a UI Framework as explained in the question above. Within this framework I would like to provide a collection view that will resize the cell size when the device is rotated. Due to the above request, I can not link to any UIViewController to detect the rotation. – Ham Dong Kyun Jul 30 '17 at 06:09

How can you tell a device has rotated so you can reload a UICollectionView

1 Answers1