This document discusses ANR (Application Not Responding) errors in Android. It defines an ANR as occurring when the main thread is blocked for over 5 seconds. Potential causes of ANRs include slow code on the main thread, heavy I/O on the main thread, lock contention, deadlocks, and slow broadcast receivers. The document provides examples and recommends using systrace to debug ANRs by capturing a trace file to understand the root cause.

1. ANR (Application Not Responding)

2. ANR (Application Not Responding)
Presentation isn’t responding.
Do you want to close it?
Wait OK

3. AGENDA:
Pre-requisites
What is an ANR?
Debugging an ANR

4. LETS SEE A SHORT STORY

5. COOK
ORDER LIST
GIVE ME 2
BANANAS.
WILL BE RIGHT
BACK!!

6. COOK
TIME: 10ms
GOT IT!!
ORDER LIST

7. COOK
TIME: 10ms
HERE IT IS!!
GOT IT!!
ORDER LIST

8. CASE II

9. COOK
GIVE ME A
PIZZA.
WILL BE RIGHT
BACK!!
ORDER LIST

10. COOK
COOKING
PIZZA!!
ORDER LIST

11. COOK
COOKING
PIZZA!!GIVE ME A CUP
OF TEA.
ORDER LIST

12. COOK
COOKING
PIZZA!!
ORDER LIST

13. COOK
COOKING
PIZZA!!
TIME: 1s2s3s4s5s
???
ORDER LIST

14. COOK
ORDER LIST
COOKING
PIZZA!!
TIME: 5s
Application isn’t responding.
Do you want to close it?
Wait OK
CHEF

15. UI Thread
Task Queue
TIME:
Resources
DRAW A
BUTTON!
COMPUTING!
10ms
DONE!!
CLICK ME!

16. UI Thread
Task Queue
TIME:
Resources
PROCESS BACK KEY
EVENT!
FILTER THIS HUGE
LIST!
FILTERING!!
1s2s3s4s5s

17. UI Thread
Task Queue
TIME:
Resources
FILTERING!!
5s
Application isn’t responding.
Do you want to close it?
Wait OK

18. Slow code on the Main Thread.
Heavy I/O on the Main Thread.
Lock Contention.
Deadlocks.
Slow Broadcast Receiver.
WHAT CAUSES AN ANR?

19. 1. SLOW CODE ON THE MAIN THREAD

20. 1. SLOW CODE ON THE MAIN THREAD
No heavy
computations
allowed!

21. 2. HEAVY I/O ON THE MAIN THREAD

22. 2. HEAVY I/O ON THE MAIN THREAD

23. 3. LOCK CONTENTION

24. LET’S TURN THE PAPER
BLACK!
THE PAPER IS BLACK &
WHITE!

25. GOTTA WAIT FOR THAT PAPER TO
BE FREE!
Shared Resource

27. < Setters for builder class >

28. SampleApplication
< Initial data set >

29. SampleApplication

34. ?
SampleApplication
< Initial data set >

35. 4. DEADLOCK

37. Artist

38. Player
Pen fight!

39. Artist
Player
Pen fight!

40. Artist
Player
Pen fight!
DEADLOCK

41. 5. SLOW BROADCAST RECEIVER

42. Strict Mode!
DEBUGGING AN ANR:

43. DEBUGGING AN ANR:
1. Capture a ‘trace’ file.
?

44. DEBUGGING AN ANR:
(UNDERSTANDING THE ROOT CAUSE)
2. Systrace.
Catapult

45. DEBUGGING AN ANR:
(UNDERSTANDING THE ROOT CAUSE)
2. Systrace.

46. DEBUGGING AN ANR:
(WHAT IS A SYSTRACE?)
Systrace
SYSTRACE
fTraceaTrace

47. DEBUGGING AN ANR:
(WHAT IS A SYSTRACE?)
SYSTRACE
fTraceaTrace
Systrace

48. DEBUGGING AN ANR:
(WHAT IS A SYSTRACE?)
SYSTRACE
fTrace
aTrace
Systrace

49. DEBUGGING AN ANR:
(WHAT IS A SYSTRACE?)
SYSTRACE
fTrace
aTrace
Systrace

50. DEBUGGING AN ANR:
(CAPTURING A SYSTRACE)
android-sdk/platform-tools/systrace/
$ python systrace.py [options] [categories]

51. BONUS SECTION!
Background Thread Priority
Flattening view hierarchy
Measure Layout pass
Application initialisation
Request Layout

52. ABOUT US:
Ranit Raj Ganguly
Kavya P S
https://medium.com/@kavya.ps095
https://www.linkedin.com/in/kavya-ps095/
https://www.linkedin.com/in/ranitrajganguly/

53. THANK YOU!