What is the most efficient way of coding drag and zoom for android

I am new to processing and I’ve been looking for a while for a way to zoom and drag for my andriod app. I don’t need it to be very robust. just something to zoom in and drag around a certain sketch. I have ideas but I am mostly lost. I believe I could use the scale and transform, function. If there are any built-in function, please also let me know. Thanks a lot!