I want to create a filled rectangle to be positioned in the background, anyway it covers the textboxes I already created with vector graphics. Is there a way (I'm sure there is, I'm just struggling to find it) to move the rectangle in the background?
Could you please help me with this? Thanks.
Working from memory, no there is not.
Vector graphics is drawn in the order in which they are added to the frame, so if the text is already there and you add a rectangle then it will be over the text.
The easiest way through code to handle generating graphics using vector graphics is to use the layer value, set everything that is a fixed size to 1 layer and everything that could change to another layer, onCreate draw all of the graphics and then as needed remove all of the graphics from 1 layer only (is a method to let you do this) and then add it all back in with the correct values.
You can work with the layers manually, as well. Use -1 for the text-vectorgraphics and values >0 for the rectangles, then the text will be displayed in front of the rectangles: