protected override void OnCreate (Bundle bundle)
{
    base.OnCreate (bundle);
    global::Xamarin.Forms.Forms.Init (this, bundle);
    var metrics = Resources.DisplayMetrics;
    var widthInDp = ConvertPixelsToDp(metrics.WidthPixels);
    var heightInDp = ConvertPixelsToDp(metrics.HeightPixels);

    App.ScreenWidth = metrics.WidthPixels;
    App.ScreenHeight = metrics.HeightPixels;

    LoadApplication (new App ());
}

public int ConvertPixelsToDp(float pixelValue)
{
    var dp = (int) ((pixelValue)/Resources.DisplayMetrics.Density);
    return dp;
}