iOS故事板限制/纵向和横向视图的特征

Question

my iOS project consists at the moment of one single UIView or UIViewController. The controller class is called MainViewController.swift. The view of the view controller has a subview which I've placed at the bottom:

I've set the auto layout option to keep the distance of the subview for every device size the same:

Now I want to keep the sub view always on the short side of the parent view, which means that in landscape mode the sub view show be on the right side of the parent view:

I've checked some tutorials and other posts in the meanwhile:

• Ray Wenderlich Tutorial
• Stackoverflow Post

At this point it is not clear to my how to realize such a behavior best? Possibilites I've found to solve the issue:

• Vary for traits...but how?
• Constraints?
• Programmatically - I think this would be the fastest solution, but I really want to use storyboards and learn the correct usage.

Answer 1

Here you can play with size classes and traits. if you want give constraint in portrait mode you have to select compact width and regular height and for landscape compact width compact height.

Please go through following steps to constraint portrait and landscape separately.

1) Please select mode either landscape and portrait from traits.

2) Now, you can constraint each mode one by one. suppose i am giving constraint to red view in portrait mode and i will enable particular constraints for for portrait size class so it will be disable for landscape mode.

3)once we are finished with portrait mode i have switched to compact height compact regular size class which is landscape mode.

4) Now, we can constraint the landscape mode as shown in above screenshot.

As we can see constraints which is light in color are disable for current size class.

So this is how we can constraints landscape and portrait mode separately.

Answer 2

Because there is no size class or trait difference between an iPad in landscape, and an iPad in portrait, you will ultimately have to handle at least some cases programatically. That being the case, you might as well just handle all cases programatically with a method that does something like:

1. Get current screen size
2. If width > height, add constraints to center the subview vertical and pin it to the right edge. Otherwise, add constraints to center the subview horizontally and pin it to the bottom edge.