safeAreaLayoutGuide not updated after rotating the device

Question

I present a UIViewController out, which uses autolayout to set the constraints for the sub views inside the view of the view controller. all the constraints are kept in the code, without storyboard or xib.

I add the safeAreaLayoutGuide inside the code, such as below:

NSLayoutConstraint *const containerViewTopConstraint = [self.containerView.topAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor];

the problem is after I rotating from portrait to landscape, the view.safeAreaLayoutGuide didn't get updated. which is still the old safeAreaLayoutGuide in the portrait. wonder if I miss something? Thanks!

Answer 1

It sounds like you're misinterpreting the concept of "top"?

The layout guide does not "rotate with the device." When you rotate your phone, the self.view.safeAreaLayoutGuide.topAnchor is no longer the edge with the notch.

In these image, all 4 edges of the cyan label (top / bottom / leading / trailing) are constrained to the view's safeAreaLayoutGuide:

In these images, only the Top edge is constraint to the view's safeAreaLayoutGuide - leading / trailing / bottom are constrained to the view's respective anchors:

Answer 2

Turns out I found the reason, which is very silly, my teammate wrote the wrong code...

-(void)viewDidAppear:(BOOL)animated {
    [super viewDidDisappear:animated];
    ...
}

which cause the safeAreaLayoutGuide not be updated after rotating.

Thanks all your guys answer.