如何设置TextColor Xamarin.Forms TableSection？

Question

I am a fan of doing as much as possible in xaml, I have aTableView` with a TableSection.

<TableView Intent="Menu">
     <TableRoot>
          <TableSection Title="Test Section" TextColor="#FFFFFF">
                <TextCell Text="Test Item" TextColor="#FFFFFF"/>
          </TableSection>
     </TableRoot>
</TableView>

For TextCell TextColor="#FFFFFF" seems to work, however whenever I use this attribute on a TableSection I get this:

An unhandled exception occurred.

Is it possible to change the color of the TableSection with xaml?

Answer 1

Custom Renderers! I have two blog posts on this here:

Android: Xamarin.Forms TableView Section Custom Header on Android

iOS: Xamarin.Forms TableView Section Custom Header on iOS

Basically, create a custom view that inherits TableView , then custom renderers that implement custom TableViewModelRenderer . From there you can override methods to get the header view for the section title.

Here's what that might look like for Android:

public class ColoredTableViewRenderer : TableViewRenderer
{

    protected override TableViewModelRenderer GetModelRenderer(Android.Widget.ListView listView, TableView view)
    {
        return new CustomHeaderTableViewModelRenderer(Context, listView, view);
    }

    private class CustomHeaderTableViewModelRenderer : TableViewModelRenderer
    {
        private readonly ColoredTableView _coloredTableView;

        public CustomHeaderTableViewModelRenderer(Context context, Android.Widget.ListView listView, TableView view) : base(context, listView, view)
        {
            _coloredTableView = view as ColoredTableView;
        }

        public override Android.Views.View GetView(int position, Android.Views.View convertView, ViewGroup parent)
        {
            var view = base.GetView(position, convertView, parent);

            var element = GetCellForPosition(position);

            // section header will be a TextCell
            if (element.GetType() == typeof(TextCell))
            {
                try
                {
                    // Get the textView of the actual layout
                    var textView = ((((view as LinearLayout).GetChildAt(0) as LinearLayout).GetChildAt(1) as LinearLayout).GetChildAt(0) as TextView);

                    // get the divider below the header
                    var divider = (view as LinearLayout).GetChildAt(1);

                    // Set the color
                    textView.SetTextColor(_coloredTableView.GroupHeaderColor.ToAndroid());
                    textView.TextAlignment = Android.Views.TextAlignment.Center;
                    textView.Gravity = GravityFlags.CenterHorizontal;
                    divider.SetBackgroundColor(_coloredTableView.GroupHeaderColor.ToAndroid());
                }
                catch (Exception) { }
            }

            return view;
        }
    }
}

And the on iOS:

public class ColoredTableViewRenderer : TableViewRenderer
{
    protected override void OnElementChanged(ElementChangedEventArgs<TableView> e)
    {
        base.OnElementChanged(e);
        if (Control == null)
            return;

        var coloredTableView = Element as ColoredTableView;
        tableView.WeakDelegate = new CustomHeaderTableModelRenderer(coloredTableView);
    }



    private class CustomHeaderTableModelRenderer : UnEvenTableViewModelRenderer
    {
        private readonly ColoredTableView _coloredTableView;
        public CustomHeaderTableModelRenderer(TableView model) : base(model)
        {
            _coloredTableView = model as ColoredTableView;
        }
        public override UIView GetViewForHeader(UITableView tableView, nint section)
        {
            return new UILabel()
            {
                Text = TitleForHeader(tableView, section),
                TextColor = _coloredTableView.GroupHeaderColor.ToUIColor(),
                TextAlignment = UITextAlignment.Center
            };
        }
    }
}

Answer 2

According to the official documentation for TableSection you are out of luck. I'm afraid you would have to write a custom renderer for a subclass of the TableSection class and expose an extra property of type Xamarin.Forms.Color . Then you would be able to set the color from XAML.

Answer 3

You can set this color in the base theme (may apply to other widgets too)

In /Resources/values/styles.xml

<style name="MainTheme.Base" parent="Theme.AppCompat.Light">
    <item name="colorAccent">#434857</item>

For Individual Section Titles, the TextColor property now seems to work correctly:

<TableView Intent="Settings">
    <TableRoot>
        <TableSection Title="App Settings" TextColor="Red">