iOS Swift：显示的视图控制器为零

Question

I'm trying to know which is the presented view controller of a modal view controller shown by a modal segue..

print(self.presentedViewController) is always nil, how is it possible?

Answer 1

To get the "parent" view controller of the view controller you are in, you want to get the "presenting" controller:

print(self.presentingViewController)

If your code is in the VC that just presented a modal VC, in that code you can call:

print(self.presentedViewController)

to get a reference to the modal VC.

Answer 2

Weird, it kept returning nil in viewDidLoad , however, when I wrapped my print in timeout, it returned it correctly:

DispatchQueue.main.asyncAfter(deadline: .now() + 0.0) {
    print("test", self.presentingViewController)
}