DroidFlakes: An Android Animation Demo

Here's a simple app that I wrote recently to see how background processing affects frame rate. There's nothing too complicated going on in the app, but it seemed worth publishing to show how to do various things in Android, such as:

• Using a single ValueAnimator (3.0+ API) to animate several objects independently
• Manipulating the transform of Canvas to move/rotate objects
• Using the GPU to provide faster rendering (3.0+ capability)
• Tracking the current frames per second performance

Here's a video of the running application, captured using HDMI on a 3.1 tablet. You can see how the More, Less, and GPU controls affect what's going on in the app. Note that it starts out with no GPU acceleration and bogs down when we have lots of flakes on the screen. Then see how the frame rate improves once the GPU box is checked. The app is accelerated by default; non-GPU rendering is performed by setting a software layer on the view, which forces rendering to happen in software to a bitmap, which is then copied into the view.

Here's the code (a zipped Eclipse project for the app). You should be able to build/run it for any 3.0+ target device.

Note: this is not the Renderscript app that I showed in a recent user group talk. That other app is based on this one, but uses Renderscript to animate and draw the droidflakes. This version just uses the standard Canvas API to draw bitmaps. I'll post the Renderscript version soon.