Top "Viewdidlayoutsubviews" questions

UIViewController viewDidLayoutSubviews

I am having difficulty figuring out why Erica Sadun does the following (calling viewDidAppear in viewDidLayoutSubviews) in her cookbook example …

ios viewdidlayoutsubviews
What's exactly viewDidLayoutSubviews?

I was reading the description of viewDidLayoutSubviews of UIViewController: Called to notify the view controller that its view has just …

ios uiviewcontroller uikit bounds viewdidlayoutsubviews
Why viewDidLayoutSubviews is called twice only on first run?

It's driving me crazy this. Only on first run the viewDidLayoutSubviews is called twice. Here is the code I'm using: …

ios swift2 viewdidlayoutsubviews