How do I resize my UITableView using Autolayout?

Question

I have a UITableView in a ViewController in a Storyboard (not a UITableViewController). What I want to do is add a custom UIView above the TableView in code. When the View is not there, the TableView's top anchor is anchored to PrimaryNavCollectionViewOutlet. I store this constraint as an outlet, and then if I have to add the View, I can use this outlet to remove the storyboard constraint.

I then constrain the inserted View to be below where the TableView was, and constraint the TableView to be below that.

Here's my code:

if (_viewAboveTableView != null)
{
     TableView.RemoveConstraint(TableViewTopConstraint);
                
     View.AddSubview(_viewAboveTableView);
     _viewAboveTableView.TranslatesAutoresizingMaskIntoConstraints = false;
     TableView.TranslatesAutoresizingMaskIntoConstraints = false;
     _viewAboveTableView.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor).Active = true;
     _viewAboveTableView.TopAnchor.ConstraintEqualTo(PrimaryNavCollectionViewOutlet.BottomAnchor).Active = true;
     _viewAboveTableView.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor).Active = true;
     _viewAboveTableView.BottomAnchor.ConstraintEqualTo(TableView.TopAnchor).Active = true;
}

Unfortunately, when I run it, I can't see _viewAboveTableView. I feel like I'm missing something easy, but I can't figure out what. I've tried LayoutIfNeeded() and a few other methods on the View, but they don't make it appear. What have I missed?

You could post the full code of `add a custom UIView above the TableView in code` . It seems have some constraint conflicts . — Lucas Zhang, Mar 30 '21 at 01:22
It's pretty much all that I've posted. What are the conflicts you're seeing? — Chucky, Mar 30 '21 at 08:23
Where did you add the custom view ? Post the relevant code . — Lucas Zhang, Apr 01 '21 at 03:16

score 0 · Answer 1 · answered Mar 30 '21 at 01:23

Add height constraint to _viewAboveTableView. Or
Make sure _viewAboveTableView has content that will specify intrinsic content size -- it should have properly laid-out subviews with content size (intrinsic or explicit via layouts. e.g. image, label etc.)

My guess is _viewAboveTableView is not getting inflated because it doesn't specify intrinsic content size (height > 0). If it's wrong constraints, you should be able to see it in the console.

score 0 · Accepted Answer · answered Apr 01 '21 at 11:40

It looks like the problem with what I was doing was that TableView.RemoveConstraint(TableViewTopConstraint); didn't have the intended effect.

From this answer I learned that RemoveConstraint is, or is about to be, deprecated in favour of TableViewTopConstraint.Active = false;. This made my code work the way that was intended.

How do I resize my UITableView using Autolayout?

2 Answers2