Drawing on the canvas of a SurfaceView

Even after inheriting from View for custom drawing code, we are limited to Android's determination and frequency to actually redraw the view.

How to do it...

Drawing on a View instance requires that the drawing occurs within the UI update cycles as well as on the UI thread. This provides limitations that can be avoided by drawing on a SurfaceView instance from another thread:

1. In order to draw on a SurfaceView instance, we need a Surface instance to draw on. Thus, we need to know when the surface is created and destroyed:

   public class MainActivity :
     Activity, ISurfaceHolderCallback {
     private ISurfaceHolder surfaceHolder;
     public void SurfaceChanged(
       ISurfaceHolder holder, Format format,
     int width, int height) {
     }
     public void SurfaceCreated(ISurfaceHolder holder) {
       surfaceHolder = holder;
     }
     public void SurfaceDestroyed(ISurfaceHolder holder) {
       surfaceHolder = null
     }
   }

2. Then, we need to get hold of the ISurfaceHolder instance...