MissingMethodException for custom renderer

Question

When loading my MainPage Visual Studio goes into break mode with the following error

System.MissingMethodException: Default constructor not found for type Test.Renderers.PostListViewAndroid

I updated my Custom Renderer class to support 2.5 since Context is obsolete as of version 2.5

My custom renderer is

[assembly: ExportRenderer(typeof(PostListView), typeof(PostListViewAndroid))]
namespace SocialNetwork.Droid.Renderers
 {
public class PostListViewAndroid: ListViewRenderer
{

    public PostListViewAndroid(Context context) : base(context)
    {

    }

    protected override void OnElementChanged(ElementChangedEventArgs<ListView> e)
    {
        base.OnElementChanged(e);
        Control.SetSelector(Android.Resource.Color.Transparent);
    }
}
}

And the PostListView is simply

public class PostListView : ListView
{
}

Answer 1

If you are using Xamarin.Forms >= 2.5 you need to use ListViewRenderer(Context context) : base(context) as you know

This is the source for the current ListViewRenderer

public class ListViewRenderer : ViewRenderer<ListView, AListView>, SwipeRefreshLayout.IOnRefreshListener
{
    ...

    public ListViewRenderer(Context context) : base(context)
    {
        AutoPackage = false;
    }

    [Obsolete("This constructor is obsolete as of version 2.5. Please use ListViewRenderer(Context) instead.")]
    public ListViewRenderer()
    {
        AutoPackage = false;
    }

Notice the Obsolete Attribute, meaning you don't need it. However it seems your problem is that your packages and references are out of alignment. Id try the following steps

Step 1

1. Clean Solution
2. Delete bins and objs directions in all projects
3. Restart visual studio
4. Rebuild

---

Step 2

Try updating all packages for solution in the package package console

Update-Package  –reinstall

After this step, if it still hasn't worked try step 1 again

Answer 2

If base class does not have default empty constructor (in your case ListViewRenderer) - you cannot do this. If it has, then add below

public PostListViewAndroid()
    {

    }

Its for simple reason : when derive class in instantiated, first base class constructor is invoked for initialization. So if there is no default constructor in base class, its not going to work out.