| CanvasWatchFaceService | Base class for watch faces that draw on a Canvas. | 
| CanvasWatchFaceService.Engine | The actual implementation of a watch face that draws on a Canvas. | 
| Gles2WatchFaceService | Base class for watch faces that draw using OpenGL ES 2.0. | 
| Gles2WatchFaceService.Engine | The actual implementation of a watch face that draws using OpenGL ES 2.0. | 
| WatchFaceService | A subclass of WallpaperServicewith aWallpaperService.Enginethat exposes
 callbacks for the lifecycle of a watch face. | 
| WatchFaceService.Engine | The actual implementation of a watch face. | 
| WatchFaceStyle | A style descriptor for watch faces. | 
| WatchFaceStyle.Builder | Builder for WatchFaceStyle objects. |