Yes, You Can add constraints to all subviews in the scrollview.
If you add constraints to all subviews,
- you don't need to set the content size and content size will be automatically calculated in runtime based on your constraints.
- you don't need to set frames to views.
- No worry about orientation support.
- No worry about 3.5/4 inch iPhones.
So better to use Auto Layout to views.