topLayoutGuide in child view controller

Question

I have a UIPageViewController with translucent status bar and navigation bar. Its topLayoutGuide is 64 pixels, as expected.

However, the ch

Answer 1

you can add a constraint in the storyboard and change it in viewWillLayoutSubviews

something like this:

- (void)viewWillLayoutSubviews
{
    [super viewWillLayoutSubviews];
    self.topGuideConstraint.constant = [self.parentViewController.topLayoutGuide length];
}