Google map screenshot always black screen

I want to take google map screenshot in my xamarin PCL Project. The map is displaying perfectly. But when i try to take a screenshot it is displaying a black screen for the map part. But extra part of the screen is capture perfectly. When i try to take screenshot from another app, i can take perfectly. I am using the below code.

My interface

public interface IScreenshotService { Task<byte[]> Capture(); }
`
public class ScreenshotService : IScreenshotService
{
public static Activity Activity { get; set; }

public async System.Threading.Tasks.Task<byte[]> Capture()
{
    if (Activity == null)
    {
        throw new Exception("You have to set ScreenshotManager.Activity in your Android project");
    }

    var view = Activity.Window.DecorView;
    view.DrawingCacheEnabled = true;

    Bitmap bitmap = view.GetDrawingCache(true);

    byte[] bitmapData;

    using (var stream = new MemoryStream())
    {
        bitmap.Compress(Bitmap.CompressFormat.Png, 0, stream);
        bitmapData = stream.ToArray();
    }

    return bitmapData;
}

}

`

Code to for calling function

byte[] screenshotData = await DependencyService.Get<IScreenshotService>().Capture();