Drawable

ShapeDrawable
Demonstrates creating Drawables in XML.

OpenGL|ES

CameraPreview
Demonstrates capturing the image stream from the camera, drawing to a surface (extending SurfaceView) on a separate thread (extending Thread).
GL SurfaceView
Demonstrates how to perform OpenGL rendering in to a SurfaceView.
Code:
GLSurfaceViewActivity.java, GLSurfaceView.java
Layout:
hello_world.xml
PolyToPoly
Demonstrates calling the Matrix.setPolyToPoly() method to translate coordinates on a canvas to a new perspective (used to simulate perspective).
DrawPoints
Demonstrates using the Paint and Canvas objects to draw random points on the screen, with different colors and strokes.
PathEffects
Demonstrates the use of Path and various PathEffect subclasses.
SurfaceView Overlay
Shows how you can place overlays on top of a SurfaceView.
Code:
SurfaceViewOverlay.java, GLSurfaceView.java
Layout:
surface_view_overlay.xml
TouchPaint
Demonstrates the handling of touch screen events to implement a simple painting app.