When is preferredContentSize respected?

Question

I have a table view controller which get it's content set after viewDidLoad. When setting the new content I calculate the preferredContentSize. Before I present the popover I can query the preferredContentSize of my view controller, which is correct. But after the presentation I get the standard size of the popover (320x480). If I use setPopoverContentSize:animated: with the before queried values everything works.

My question now is why doesn't it respect the preferredContentSize right in the beginning? What I'm doing wrong?

Answer 1

Now I had the same problem another time. If I put my table height calculation into viewWillAppear than it works:

public override void ViewWillAppear (bool animated)
{
    base.ViewWillAppear (animated);

    TableView.LayoutIfNeeded ();
    this.PreferredContentSize = new SizeF (320f, TableView.ContentSize.Height);
}

The code is in C# but you can easily convert it to Objective-C or Swift.

Answer 2

I converted testing’s code to Swift 2.0.

override func viewWillAppear(animated: Bool) {
   super.viewWillAppear(animated)
   tableView.layoutIfNeeded()
   preferredContentSize.height = tableView.contentSize.height
}