I was wandering if is there a way to specify several layers in a layer-list XML file and tell each layer to blend according to a specific XferMode from PorterDUff.
It would be very useful to generate composite backgrounds.
Neither the XML form nor the POJO representing a LayerList provide access to such methods to define a XferMode.
Nevertheless, you could use the layer list as a "Drawable info" storage mechanism, and paint it in a custom way using method such as getNumberOfLayers and getDrawable().
Inside your loop, you can easily change to whatever PorterDuffMode you want between layers. Unfortunately it doesn't seem possible to store all the information you need inside the native XML files for layer-lists, and I don't know of any image format that would let you do see neither.