Xamarin.Forms custom Android NavigationPageRenderer title and subtitle - xamarin

Question

Currently working on a project where I want to use AppCompat and have a requirement setting title and subtitle on most of the pages.
It doesn't work using AppCompat at all - neither setting the properties nor using a custom view.
When not using AppCompat both works as expected. The full source code is available here so just run the app if you're curious :)
using System.ComponentModel;
using Android.App;
using Android.Widget;
using App1.Droid.Renderers;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
#if __APPCOMPAT__
using NavigationRenderer = Xamarin.Forms.Platform.Android.AppCompat.NavigationPageRenderer;
#else
using NavigationRenderer = Xamarin.Forms.Platform.Android.NavigationRenderer;
#endif
[assembly: ExportRenderer(typeof(NavigationPage), typeof(NavigationPageRenderer))]
namespace App1.Droid.Renderers
{
public class NavigationPageRenderer : NavigationRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<NavigationPage> e)
{
base.OnElementChanged(e);
SetCustomView(e.NewElement.CurrentPage.GetType().Name);
}
private void SetCustomView(string view)
{
var activity = (Activity)Context;
#if __APPCOMPAT__
var actionBar = ((FormsAppCompatActivity)Context).SupportActionBar;
#else
var actionBar = activity.ActionBar;
#endif
actionBar.Title = view;
actionBar.Subtitle = " -> " + view;
var abv = new LinearLayout(activity)
{
Orientation = Orientation.Vertical
};
var main = new TextView(activity)
{
Text = view,
};
main.SetTextColor(Color.Aqua.ToAndroid());
main.SetPadding(4, 4, 2, 6);
abv.AddView(main);
abv.AddView(new TextView(activity)
{
Text = " -> " + view
});
actionBar.SetDisplayShowCustomEnabled(true);
actionBar.CustomView = abv;
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName.Equals("CurrentPage"))
{
SetCustomView(((NavigationPage)sender).CurrentPage.GetType().Name);
}
}
}
}
Edit: Thanks #jimmgarr. Altered the code slightly to keep alternating between AppCompbat and "normal mode". The code is available here

Answer 1

So it looks like the NavigationPage uses its own Toolbar instance. That's why setting the properties on SupportActionBar isn't doing anything.
I was able to get it working by overriding OnViewAdded() to get a reference to the new Toolbar when it's added:
public override void OnViewAdded(Android.Views.View child)
{
base.OnViewAdded(child);
if (child.GetType() == typeof(Support.Toolbar))
toolbar = (Support.Toolbar)child;
}
Then using the reference inside SetCustomView() to set only the Subtitle since the Title is already set automatically.
Here's the complete renderer class :)