Adding text annotation to figure programmatically

I would like to add text annotation to a figure from a GUI made with GUIDE. First I plot some data, than when the user clicks on a checkbox I call the text function in the event handler like this:

text(obj.XData(q), obj.YData(q)+10, int2str(q), 'Units', 'pixels');

obj is the line object itself, q is a counter for each point in the plot. It runs without errors, but nothing happens. I suppose I should 'refresh' the axis somehow, but refresh command doesn't help and I haven't found anything in the documentation.

Edit: I have found out that my code was wrong: pixel units correspond to a coordinate s开发者_Go百科ystem where the origin is the lower-left corner of my axis control, what is not the same as my data coordinate system. I fixed this problem with ds2nfu, and when I paint before plotting everything is fine. But after plotting I see nothing. Is it possible that there is some kind of z-order problem with annotations?

As I mentioned in the comments, you should use the normalized units to place things in the same coordinate system as the data.

Now for the other problem. I'm not sure if this is a z-order issue, but if it is, you can bring the text to the front using UISTACK:

hText = text(x,y,'str');
uistack(hText, 'top')