如何知道当前的大小类以及我的按钮是否显示？

Question

I use size classes in my projet.

I have a button, which is displayed only for

• Compact Width and Compact height
• Compact width and Regular height

This button isn't displayed for other size classes.

On this button I apply a specific effect. But I need to apply this effect ONLY for my 2 sizes classes.

Something like :

if button is available for the current size classe
    apply the effect

Is it possible to implement ?

Answer 1

To follow up on my now-deleted previous answer and subsequent comment, Apple's docs state that

A runtime object for an uninstalled view is still created. However, the view and any related constraints are not added to the view hierarchy and the view has a superview property of nil. This is different from being hidden. A hidden view is in the view hierarchy along as are any related constraints.

In other words, the only way to know is to check whether the outlet view's parent view is nil .

Answer 2

During ViewWillApper() check the traitCollection of your View Controller.

myViewController: UIViewController{

    mybutton = UIButton(frame: myframe)

    func viewWillAppear(){

        if traitCollection.horizontalSizeClass == .Compact {
            applyAwesomeEffect(myButton)
        }
    }
}