Android :: Use Callbacks In Own Code

Here I update my world to include the canvas size. world.getViewPort().updateViewPortSize(width,height); Is there a better way to do this? Is there a way that I can automatically update my world object without having to manually call it in the setSurfaceSize method but instead call it from My world class? My guess is that I can use some sort of callback, but I don't understand them!

/* Callback invoked when the surface dimensions change. */
public void setSurfaceSize(int width, int height) {
// synchronized to make sure these all change atomically
synchronized (mSurfaceHolder) {
mCanvasWidth = width;
mCanvasHeight = height;
world.getViewPort().updateViewPortSize(width,height); }