约束不明确地表明表格视图单元格的内容视图的高度为零

Question

This warning is driving me crazy:

[Warning] Warning once only: Detected a case where constraints ambiguously suggest a height of zero for a tableview cell's content view. We're considering the collapse unintentional and using standard height instead.

I have a UICollectionView inside a UITableViewCell. The table view cell has auto row height, and the collection view has cell size of 44x44. The collection view cell has default size. I have a button inside the collection view cell with constraints pinning it to the top, bottom, left, and right of the cell (I also tried manually setting its size to 44x44). You can see the rest of the constraints in the following image:

When I try to set the Table View Cell Row Height as custom equal to 44, I get an error that the constraints are conflicting and one of them needs to be removed. When I set it to 50, I get the warning above again.

Any ideas? :S

Thanks!

Answer 1

CollectionView constraints are wrong, you added top constraint and also aligning collectionView center vertically, remove one of them. also take a look of screen short.

Answer 2

make sure in your cell class to define constraints in a such way that cell contentView will have a least 1px height/width (eg height constraint >= 1)

I do like this (collectionView is a subview of cells contentView)

collectionView.heightAnchor.constraint(greaterThanOrEqualToConstant: 1).isActive = true