What is Nslayoutconstraint?

Returns the optimal size of the view based on its current constraints. iOS 6.0+ iPadOS 6.0+ Mac Catalyst 13.1+

The relationship between two user interface objects that must be satisfied by the constraint-based layout system .

Stack views are a powerful tool for quickly and easily designing your user interfaces . Their attributes allow a high degree of control over how they lay out their arranged views. You can augment these settings with additional, custom constraints; however, this increases the layout’s complexity.21 Mar 2016

Overview. Stack views let you leverage the power of Auto Layout , creating user interfaces that can dynamically adapt to the device’s orientation, screen size, and any changes in the available space. The stack view manages the layout of all the views in its arrangedSubviews property.