UIView Constraints Settings iOS Storyboard

Question

I want to specify leading, trailing constraints for one of my UIView object. But when I set that I was getting following kind of red warning:

Details about constraints error:

Why I was getting this kind of error that is big question in my mind!! I have tried with multiple combination of constraints too because I am aware that constraints always need in combination.

Edit

Set all 4 constraints:

How can I solve this error?

Answer 1

For the constraints in iOS development, you must define constraints for both side: vertical and horizontal. Like in the picture, you've created only constraints for horizontal side. The XCode requires the vertical side (top, botom, center_vertical, height)