This code snippet demonstrates how to draw a filled rectangle on a PDF page using the RadaeePDF SDK for Android. The drawRect function takes a Page object, an array of floats representing the rectangle's coordinates (top-left and bottom-right corners), and an integer representing the fill color. The function creates a PageContent object, defines a path for the rectangle using the Path class, fills the path with the specified color, and finally adds the content to the page.  

/**
 * Adds a rectangle to the given page content.
 * 
 * @param page the pdf page object
 * @param rect the PDF coordinates of the rectangle to be drawn.
 * @param fillColor the rectangle fill color
 */
 public static void drawRect(Page page, float[] rect, int fillColor) {
     PageContent content = new PageContent();
     content.Create();
     content.GSSave();
 
     // draw a rectangle
     Path path = new Path();
     path.MoveTo(rect[0], rect[1]);
     path.LineTo(rect[2], rect[1]);
     path.LineTo(rect[2], rect[3]);
     path.LineTo(rect[0], rect[3]);
     path.ClosePath();
 
     //fill it
     content.SetFillColor(fillColor);
     content.FillPath(path, true);//using winding fill rule
     content.GSRestore();
 
     //destroy the path
     path.Destroy();
 
     //add content to page
     page.AddContent(content, true);
     content.Destroy();
 }