How can I customize the UI?

You have different methods to customize the GUI:

• Choose between two different styles: rectangle or laser.
• Change the color of the viewfinder: setViewfinderColor

mBarcodePicker.getOverlayView().setViewfinderColor(0, 0.4f,0.8f); 

     and  the color of the viewfinder once the barcode has been recognized: setViewfinderDecodedColor

mBarcodePicker.getOverlayView().setViewfinderDecodedColor(0, 0.4f, 0.8f);

• Change the dimension: setViewfinderDimension

mBarcodePicker.getOverlayView().setViewfinderDimension(0.7,0.3,0.4,0.3);

• Disable the viewfinder and insert a new view into the root view

mBarcodePicker.getOverlayView().drawViewfinder(false);
rootView.addView(newViewFinder, rParams);