UILabel not wrapping in UITableView until device rotate (iOS8) - xamarin.ios

Question

I have a custom MvxTableViewCell that is associated with an MvxStandardTableViewSource. That Source is then applied to a UITableView. The custom table cell is defined without any Storyboard or NIB. It is laid out in code and uses AutoLayout.
this.searchResultsTable = new UITableView();
this.searchResultsTable.AccessibilityIdentifier = "SearchView_SearchResultsTable";
this.searchResultsTable.TranslatesAutoresizingMaskIntoConstraints = false;
this.searchResultsTable.RowHeight = UITableView.AutomaticDimension;
this.searchResultsTable.EstimatedRowHeight = 44.0f;
this.searchResultsTable.RegisterClassForCellReuse(typeof(CustomerItemCell), new NSString("CustomerItemCell"));
this.searchResultsTable.AllowsMultipleSelectionDuringEditing = true;
this.searchResultsTable.TableFooterView = new UIView();
this.searchResultsTableDataSource = new MvxStandardTableViewSource(this.searchResultsTable, new NSString("CustomerItemCell"));
this.searchResultsTable.Source = this.searchResultsTableDataSource;
The MVxStandardTableViewSource is databound to a ViewModel property of type List
var set = this.CreateBindingSet<SearchView, SearchViewModel>();
set.Bind(this.searchResultsTableDataSource).To(vm => vm.SearchResults);
set.Bind(this.searchBar).For(x => x.Text).To(vm => vm.CurrentSearchCriteria);
set.Apply();
This all works fine until an item in the data source causes some text wrapping in one of the UILabels and consequently a different height to the other cells.
The cell height is mostly correctly calculated but the UILabel within the
cell does not get redrawn until the device is rotated. I am using iOS AutoLayout to layout the various UIViews in the Cell.
Here are some examples of the large cell in my layout, see the
person "THISISAPATIENTWITHA-" (note this is test data not real people's data)
Initial display of cells
Same cells but device has been rotated
Still the same cells with device rotated back to original
How do I get the UILabel to redraw? We only need to support iOS8 and above.
I cannot see an event or method that gets called when the data binding has happened that would allow me to effectively tell the custom cell "You now have your subviews populated with bound data so redraw them"
The table has another issue too that is covered by this question, Implementing cell reuse for varying height cells in UITableView
Simple Repro on Github
https://github.com/munkii/TableCellResizeIssue

Answer 1

UPDATE:
I've forked your GitHub project and submitted a pull request. But here's my updates to your project.
https://github.com/SharpMobileCode/TableCellResizeIssue
First, you're using FluentLayout for your constraints. Nothing wrong with that actually, but that's some good info to tell others. :)
Second, in order for UITableView.AutomaticDimension to work on TableView Cells, there must be enough autolayout constraints defined in order for the cell to calculate the height of the cell. UITableView.AutomaticDimension depends on proper AutoLayout constraints.
Since you were using FluentLayout to abstract iOS AutoLayout constraints, this was not obvious as no warnings were present in the application output window. Though FluentLayout was technically correct, it however wasn't enough for UITableView.AutomaticDimension to automatically calculate each cell height.
So what I did was added a few more constraints. Look in CustomerItemCell.CreateView() in the pull request (or my github link). You can see that I added additional constraints for all the bottom labels so that they add a Bottom Constraint to the ContentView (Just like you did with this.bornLabel). This had to be applied to all the labels on the bottom of the cell. This gives AutoLayout enough information to properly calculate the cell height.
Third, This almost works, but if you rotate to Landscape, you'll notice that the long name cells will be bigger and have extra padding. To fix this, I created another class called AutoLayoutLabel that inherits from UILabel. I overrode the Bounds property so that it changes the PreferredMaxLayoutWidth to the proper width when rotated to Landscape, and back to Portrait. You then will need to use AutoLayoutLabel instead of UILabel. You'll need this for all labels that need to wrap. I'm not sure how to set PreferredMaxLayoutWidth to auto in code, but this is how to do it programmatically (which also works for iOS 7).
public class AutoLayoutLabel : UILabel
{
public override CGRect Bounds
{
get
{
return base.Bounds;
}
set
{
base.Bounds = value;
if(this.Lines == 0 && Bounds.Size.Width != PreferredMaxLayoutWidth)
{
PreferredMaxLayoutWidth = Bounds.Size.Width;
SetNeedsUpdateConstraints();
}
}
}
}
Well, that should do it!

Answer 2

I now have a solution to this part of my issue. Prompted by #SharpMobileCode reference to PreferredMaxLayoutWidth I decided to give that another go. Rather that setting it to Automatic (which seems impossible in code) I am setting it Explicitly, once AutoLayout has done its thing. Like this
/// <summary>
/// Lays out subviews.
/// </summary>
public override void LayoutSubviews()
{
base.LayoutSubviews();
this.nameLabel.PreferredMaxLayoutWidth = this.nameLabel.Frame.Size.Width;
}
I am no longer seeing the Labels not wrap (hurrah!) however I am seeing an issue with what looks like cell reuse. Once I scroll all of the cell off the top of the screen I can scroll it back on and it has reverted to the same height as all the other cells. I can see the label is still wrapping but the cell height is wrong.

Answer 3

The standard table views in MvvmCross date back to iOS4 - while the new UITableViewAutomaticDimension sizing wasn't really added until much more recently (iOS8?)
Most real apps tend to use custom cells rather than the standard ones, but if you do want to use the standard ones, then I'd guess you could try adding some code to the setters in the cell which would trigger resize recalculations - e.g. to setters in https://github.com/MvvmCross/MvvmCross/blob/3.5/Cirrious/Cirrious.MvvmCross.Binding.Touch/Views/MvxStandardTableViewCell.cs#L73
I would guess that judiciously placed calls in there to request layout recalc would cause the parent cell and table to redraw.