I looked into the internals of UIImageView a bit. I would recommend to not fixing this in a universal way. UIImageView is specifically optimized for performance and does not use the usual way to provide the contents of the CALayer that backs the UIImageView.
Furthermore we cannot trigger a recreation of the contents of the UIImageView layer as if it get’s cleared and we call setNeedsDisplay on it it goes trough the normal flow to assign the contents to a layer via the CALayerDelegate methods. Unfortunately UIImageView does not do it, it actually does not implement some of the methods at all, so nothing will show up. It’s getting better, by calling setNeedsDisplay on an UIImageView layer it actually clears the contents and nothing is visible anymore. So we have to be careful to not calling that too.
Unfortunately I didn’t find a way yet to trigger a recreation of the UIImageView layers content except calling the private _updateState method.
That said it’s different for layers of other UIKit components like UILabel for example. Clearing the contents of a UILabel layer and calling setNeedsDisplay on the layer usually recreates the contents of the it and it will show up again.
This commit prevents to clear the contents of a layer for all wrapped UIKit and instead only NOT clear the content if the node wraps a UIImageView otherwise we should clear the contents of the layer to reclaim memory as usual.
23736c3cf7