In this lecture we'll show you some of the low-hanging fruit for UI optimization of your Android applications.

1. UI optimization of android
applications
Dino Kovač

2. Rules of optimization
1.Don’t.!
2.Don’t… yet.!
3.Profile before optimizing!

3. –Donald Knuth
“Premature optimization is the root of all evil.”

4. Tools
• Hierarchy Viewer!
• “Show GPU Overdraw” (Developer options, android
4.2+)

5. Example app
• One relevant activity!
• Two lists!
• A compound view as the
right list item

6. View tree

7. How android draws views
1. measure pass - each view stores it’s
measurements!
2. layout pass - each view positions it’s children!
3. draw pass - each view draws itself

8. Focus of optimization
• Flattening layout hierarchy!
• Minimizing overdraw

9. Layout simplification

10. <merge />

11. <merge />

12. Overdraw
• Pixels get drawn more
than once!
• blue(2), green(3), light
red(4), dark red(5)!
• mostly multiple
backgrounds

13. Tweaking the selector

14. Overdraw before/after

15. Some numbers
Hierarchy
depth
Total
views
Measure Layout Draw Total
Before 9 76 0.354 1.7792 3.3624 5.4956
After 8 52 0.3402 1.0984 2.7098 4.1484

16. References
• http://c2.com/cgi/wiki?RulesOfOptimization!
• http://www.youtube.com/watch?v=URyoiAt8098!
• http://www.youtube.com/watch?v=-FUw8HMbmBQ!
• http://android-developers.blogspot.com/2009/03/android-
layout-tricks-3-optimize-by.html!
• http://developer.android.com/training/improving-layouts/
optimizing-layout.html!
• https://github.com/reisub/android_uioptimizationexample