How to access Android Activity Context from DependencyService after Forms.Context deprecated

Hi,

I implemented a DependencyService to display a dialog with EditText to get user input. Normally I created a AlertDialog.Builder with new AlertDialog.Builder(Forms.Context);

But after updated Xamarin.Forms it says that the Forms.Context is deprecated. And I don't think it is a good idea to create a static property for MainActivity to access its instance. Since I don't know much about how Android manages activity instances.

Here's my code for Android implementation of the service

[assembly: Dependency(typeof(MyApp.Droid.DependencyService.MessagePrompt))]
namespace MyApp.Droid.DependencyService
{
    class MessagePrompt : IMessagePrompt
    {
        async Task<MessagePromptResult> IMessagePrompt.DisplayPromptAsync(string title, string message, string positiveButton, string negativeButton, string placeholder)
        {
            var completionSource = new TaskCompletionSource<MessagePromptResult>();

            var builder = new AlertDialog.Builder(Forms.Context);

            if (title != null)
                builder.SetTitle(title);

            if (message != null)
                builder.SetMessage(message);

            var input = new EditText(Forms.Context)
            {
                Left = 10,
                Right = 10,
                InputType = Android.Text.InputTypes.TextVariationShortMessage,
                Hint = placeholder
            };
            builder.SetView(input);

            builder.SetPositiveButton(positiveButton, (s, e) =>
            {
                completionSource.SetResult(new MessagePromptResult(true, input.Text));
            });
            builder.SetNegativeButton(negativeButton, (s, e) =>
            {
                completionSource.SetResult(new MessagePromptResult(false, null));
            });

            builder.Show();

            return await completionSource.Task;
        }
    }
}