UICollectionViewCell有2个单元格，每个单元格的高度都为“ wrap_content”

Question

I am trying to have a automatic-height cells on a CollectionView.

I have 2 different cells, that works.

When I rotate the device landscape , I change to automatic height and width. It works. But when getting back to portrait , it does not:

func checkEstimatedSize(){
    if(DeviceType.IS_IPAD || UIDevice.current.orientation == .landscapeLeft || UIDevice.current.orientation == .landscapeRight){
        if let layout = myCollectionView.collectionViewLayout as? UICollectionViewFlowLayout {
            layout.estimatedItemSize = CGSize(width: 1, height: 1)
            layout.invalidateLayout()
        }
    }else{
        if(UIDevice.current.orientation == .portrait || UIDevice.current.orientation == .portraitUpsideDown){
            if let layout = myCollectionView.collectionViewLayout as? UICollectionViewFlowLayout {
                //get width of CollectionView
                layout.estimatedItemSize = CGSize(width: 0, height: 1)
                layout.invalidateLayout()
            }
        }
    }
}

When portrait, I want width same as CollectionView but height depends on the content of the cell.

I know there is a sizeForItemAt indexPath , but how to check/set "autoheight" to a cell (or CollectionView).

Sorry, I am not an expert, that's why I am asking experts...

Thank you in advance.

EDIT:

turns out that I changed layout.estimatedItemSize = CGSize(width: myCollectionView.frame.width, height: 0) on the second else and kinda works... but now I am receiving a warning plus simulator freeze: The behavior of the UICollectionViewFlowLayout is not defined because: MyApp the item width must be less than the width of the UICollectionView minus the section insets left and right values, minus the content insets left and right values.

ideas?

Answer 1

I needed to set UICollectionViewFlowLayoutAutomaticSize to my else:

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator){
    checkEstimatedSize()
}

func checkEstimatedSize(){
    if(DeviceType.IS_IPAD || UIDevice.current.orientation == .landscapeLeft || UIDevice.current.orientation == .landscapeRight){
        if let layout = myCollectionView.collectionViewLayout as? UICollectionViewFlowLayout {
            layout.estimatedItemSize = CGSize(width: 1, height: 1)
            layout.invalidateLayout()
        }
    }else{
        if let layout = myCollectionView.collectionViewLayout as? UICollectionViewFlowLayout {
            layout.estimatedItemSize = UICollectionViewFlowLayoutAutomaticSize
            layout.invalidateLayout()
        }
    }
}

Like this works perfectly!

Thank you all!