Im getting the following exception:
0x13 in Android.App.Activity.n_OnCreate_Landroid_os_Bundle_ at /Users/builder/data/lanes/monodroid-mlion-monodroid-4.12-series/b5dc5ce9/source/monodroid/src/Mono.Android/platforms/android-19/src/generated/Android.App.Activity.cs:2178,218 C#
It is accessing the ActionBar of the activity which can be null.
The code should check if it is null before accessing the ActionBar.
The reason ive set my android theme to not use the action bar is because the is so little support for it in Xamarin forms ive wasted two weeks to work around the problems im having displaying some toolbar items.
Even your sample todo doesn't show any toolbar items.
This is now a show stopper for me.