This document discusses performance best practices for building Android apps. It provides 7 rules: 1) Avoid sluggishness by maintaining high FPS and avoiding skipped frames; 2) Use appropriate colors like gray instead of alpha layers; 3) Limit view hierarchy complexity to 3 levels using ConstraintLayout; 4) Avoid expensive calls like onLayout() and onMeasure() except for specific cases; 5) Perform IO in background threads and use object pools to reduce garbage collection; 6) Debug performance issues using tools like gfxinfo before optimizing code; 7) Treat performance regressions seriously with tests and monitor using Developer Console. The document emphasizes optimizing for smoothness over features to provide good user experience.

1. Performance: How to build
an app instead of slideshow
by Anton Minashkin

2. What is a Performance?

3. Rule #1: Slow != Sluggish

4. FPS
Frame duration
Skipped frames

5. FPS (60. Well… Almost)
Frame duration (16.667. Ok, ok, should be like that)
Skipped frames (0. Just shut up. We're all believe in it)

6. What is a Frame?

7. So why my app skips frames?

8. Overdraw

9. Overdraw

10. Overdraw

11. Alpha

12. Alpha
“Rendering of transparent pixels on
screen, known as alpha rendering, is a
key contributor to overdraw” - Android
Performance Tips

13. Alpha
Rule #2: If you need a grey color
- use the f****g grey color!

14. Alpha
This is grey!!

15. Complex View Hierarchy

16. Complex View Hierarchy
1. Less or equal 3 View levels (don’t try to
write it with symbols)
2. RelativeLayout instead of nested
LinearLayouts

17. Complex View Hierarchy
1. ConstraintLayout
2. Merge

18. Complex View Hierarchy

19. onLayout() + onMeasure()

20. onLayout() + onMeasure()
Rule #3: Don’t call it!

21. onLayout() + onMeasure()
1. Animations
2. Custom Views

22. GC( ) callsnew Object(); new Object();
new Object(); new Object();
new Object(); new Object();

23. GC() calls
1. Use object pools
2. Use mappings carefully
3. Know when Android fails

24. GC() calls
1. Do NOT create anything in onDraw()
2. Cache!

25. GC() calls
1. Strings & Fonts
2. Use Android collections

26. GC() calls
Logs:
Log.i(TAG, “User name - “ + name);

27. GC() calls
Logs:
Log.i(TAG, “User name - “ + name);
Memory Leak!

28. IO

29. IO
IO calls are blocking calls. And slow.
And sometime concurrent.

30. IO
Rule #4: Always do IO in a
background

31. RecyclerView
RecyclerView
RecyclerView
RecyclerView
RecyclerView
RecyclerView
RecyclerView
RecyclerView

32. RecyclerView
RecyclerView is not the same as
ListView. And the difference is not about
ViewHolder

33. RecyclerView
1. Use default implementations
2. Do understand how it works
3. Forget this method -
notifyDataSetChanged()

34. Rule #5: Google before code

35. How not to make it worse?

36. Rule#6: Do not look at code!
Until you know what goes wrong

37. Statistic
1. Use Developer Console
2. Consider performance issues as
bugs

38. Debugging

39. Debugging

40. Debugging
adb shell dumpsys gfxinfo <PACKAGE_NAME>

41. Do tests
1. Yes, you can write a test for performance issue
2. Yes, do it
3. Check gfxinfo

42. Rule#7: Regression matters

44. Info
To read:
d.android.com/vitals
To watch:
Android Performance Patterns on Youtube
Everything from Chet Haase
To complain (cry):
@AntonMinashkin
anton.minashkin@outlook.com
...any social network