void InitThumbnailGridAndButton()
{
thumbnailGrid = FindViewById <PdfThumbnailGrid> (Resource.Id.thumbnailGrid);
if (thumbnailGrid == null)
{
throw new IllegalStateException("Error while loading CustomFragmentActivity. The example layout was missing the thumbnail grid view.");
}
thumbnailGrid.PageClick += (sender, e) => {
fragment.PageIndex = e.P1;
(sender as PdfThumbnailGrid)?.Hide();
};
// The thumbnail grid is hidden by default. Set up a click listener to show it.
var openTumbnailGridButton = FindViewById <ImageView> (Resource.Id.openThumbnailGridButton);
openTumbnailGridButton.Click += (sender, e) => thumbnailGrid.Show();
openTumbnailGridButton.SetImageDrawable(TintDrawable(openTumbnailGridButton.Drawable, ContextCompat.GetColor(this, Resource.Color.pspdf__color_white)));
}
