c# - Xamarin how to open xamarin forms page from android project?

Question

I want to open Xamarin forms page from Xamarin Android project. On android project I created toolabar item image, where I am calling event to open page from Xamarin forms project.

Here is my MainActivity.cs toolabar image item implementation:

    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsApplicationActivity
    {
      private IMenu CurrentMenu { get; set; }
      private ImageView imgSmallC { get; set; }

      public override bool OnCreateOptionsMenu(IMenu menu)
            {
               ActionBar.DisplayOptions = ActionBarDisplayOptions.HomeAsUp | ActionBarDisplayOptions.ShowCustom | ActionBarDisplayOptions.ShowTitle | ActionBarDisplayOptions.ShowHome;  
                LayoutInflater inflater = (LayoutInflater)ActionBar.ThemedContext.GetSystemService(LayoutInflaterService);
                View customActionBarView = inflater.Inflate(Resource.Layout.actionbar_custom_view_done, null);  

                imgSmallC = (ImageView)customActionBarView.FindViewById<ImageView>(Resource.Id.ImgSmallC);

                imgSmallC.Click += (object sender, EventArgs args) =>
                {
                    StartActivity(typeof(MyPopupPage));
                };
                return base.OnCreateOptionsMenu(menu);
            }
}

In StartActivity I am calling MyPopupPage.xaml page from Xamarin forms project, but unfortunately when I am debugging project and I click on toolbar image I get such a error:

System.ArgumentException: type Parameter name: Type is not derived from a java type.

Answer 1

You can not use a Xamarin.Form based Page as an Android Activity, they are two completely different things.

You can access the Xamarin.Forms Application singleton from the Xamarin.Android project and use that to PushModelAsync or PushAsync

Example (using full Namespace):

    await Xamarin.Forms.Application.Current.MainPage.Navigation.PushModalAsync(new PushPageFromNative.MyPage());

A Dependency Service-based Example:

Interface:

using System;
namespace PushPageFromNative
{
    public interface IShowForm
    {
        void PushPage();
    }
}

Xamarin.Form-based code:

var pushFormBtn = new Button
{
    Text = "Push Form",
    VerticalOptions = LayoutOptions.CenterAndExpand,
    HorizontalOptions = LayoutOptions.CenterAndExpand,
};
pushFormBtn.Clicked += (sender, e) =>
{
        DependencyService.Get<IShowForm>().PushPage();
};

Xamarin.Android Dependancy Implementation:

async public void PushPage()
{
    // Do some Android specific things... and then push a new Forms' Page
    await Xamarin.Forms.Application.Current.MainPage.Navigation.PushModalAsync(new PushPageFromNative.MyPage());
}