2D and 3D Graphics
When writing an application, it's important to consider exactly what your graphical demands will be. Varying graphical tasks are best accomplished with varying techniques. For example, graphics and animations for a rather static application should be implemented much differently than graphics and animations for an interactive game. Here, we'll discuss a few of the options you have for drawing graphics on Android and which tasks they're best suited for.
- Canvas and Drawables
Android provides a set of
Viewwidgets that provide general functionality for a wide array of user interfaces. You can also extend these widgets to modify the way they look or behave. In addition, you can do your own custom 2D rendering using the various drawing methods contained in the
Canvasclass or create
Drawableobjects for things such as textured buttons or frame-by-frame animations.
- Hardware Acceleration
- Beginning in Android 3.0, you can hardware accelerate the majority of the drawing done by the Canvas APIs to further increase their performance.
Android supports OpenGL ES 1.0 and 2.0, with Android framework APIs as well as natively with the Native Development Kit (NDK). Using the framework APIs is desireable when you want to add a few graphical enhancements to your application that are not supported with the Canvas APIs, or if you desire platform independence and don't demand high performance. There is a performance hit in using the framework APIs compared to the NDK, so for many graphic intensive applications such as games, using the NDK is beneficial (It is important to note though that you can still get adequate performance using the framework APIs. For example, the Google Body app is developed entirely using the framework APIs). OpenGL with the NDK is also useful if you have a lot of native code that you want to port over to Android. For more information about using the NDK, read the docs in the
docs/directory of the NDK download.