Basic GUI elements or rendering text?

I've been having fun with the openXR API and been writing this "water animation" which reacts to the heartrate. https://youtu.be/7os9slgfJcU Now I'd like to display text (heartrate for example) or a simple popup window. Or it would be even nicer to recycle Android views such as AndroidPlot. Is there any way of accessing these? It's certainly possible when pressing the menu button then the menu pops up rendered on top of my app.