Pitfall: NSLayoutConstraint Breaking in UICollectionView
I encountered a weird error when using UICollectionView, where the storyboard is using autolayout.
This is the error:
Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints)
"<NSAutoresizingMaskLayoutConstraint:0x7fda61cf61e0 h=--& v=--& H:[UIView:0x7fda6411d500(50)]>"
Will attempt to recover by breaking constraint
It doesn’t crash as it is able to recover by breaking constraint.
It is weird becase:
If I try to solve by breaking the constraint, it will not layout as I wanted
I checked every constraints and they are valid and minimal; I need not remove any unwanted constraints
The problem lies with the view cell.
Somehow, the contentView must set translatesAutoresizingMaskIntoConstraints to NO.