CollectionView cell height is not automatically resizing

Question

So I am encountering some issues with a UICollectionView I have in my Xamarin iOS project.

The cells for the CollectionView are not expanding with the label in them. The label in the cell has lines set to 0 and the following constraints:

• (top, bottom, leading, trailing) to superview

• Height >= 10

In my ViewDidLoad() I setup the CollectionView as follows:

var source = new CustomCollectionViewSource(collectionView);
        collectionView.Source = source;
        collectionView.SetCollectionViewLayout(new UICollectionViewFlowLayout()
        {
            ScrollDirection = UICollectionViewScrollDirection.Vertical,
            EstimatedItemSize = new CGSize(collectionView.Frame.Width, 10)
        }, false);

        var set = this.CreateBindingSet<MainViewController, MainViewModel>();
        set.Bind(source).For(v => v.ItemsSource).To(vm => vm.DataSource);
        set.Apply();

and my CollectionViewSource

 public class CustomCollectionViewSource : MvxCollectionViewSource
{
    public IList<Item> Messages { get; set; }

    public override void ReloadData()
    {
        var list = (ItemsSource as IEnumerable<Item>).ToArray();
        Messages = list;
    }

    public CustomCollectionViewSource(UICollectionView collectionView) : base(collectionView)
    {
        collectionView.RegisterNibForCell(CustomCollectionViewCell.Nib, CustomCollectionViewCell.Key);
    }

    public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
    {
        var cell = collectionView.DequeueReusableCell(CustomCollectionViewCell.Key, indexPath) as CustomCollectionViewCell;
        cell.DataContext = Messages.ElementAtOrDefault(indexPath.Row);

        return cell;
    }
}

I am trying to have the cells be the width of the collection view and for the height to be flexible; however, whenever I populate the cells, I always get something like this: The cells are cutoff and have an ellipses at the end. I've read online that the constraints must be right to dynamically resize, so is there something I'm missing?

I also read that to get a calculated height for each cell I can load the nib of the cell, populate it, then set the size manually in a custom UICollectionViewDelegate. Cool idea, but I could find any working examples for Xamarin iOS.

Please let me know if there is something I'm missing or any other info you require. Thanks in advance!

Answer 1

1.Make your label support multiple lines by

textLabel.LineBreakMode = UILineBreakMode.WordWrap;
textLabel.Lines = 0;  

2.Set the cell estimated height

cell.estimatedItemSize = UICollectionViewFlowLayoutAutomaticSize

Things to note:

• To define the cell’s height, you need an unbroken chain of
  constraints and views (with defined heights) to fill the area
  between the content view’s top edge and its bottom edge.

• If your views have intrinsic content heights, the system uses those values. If not, you must add the appropriate height constraints, either to the views or to the content view itself.