Da Real Fragmentation Explained Codemotion 2016

Nowadays, fragmentation in Android is a fact. As developers, we have to deal constantly with random behaviors between different versions of the operating system, incomplete ROMs, different hardware qualities, manufacturers that modify the specs of some APIs or even ignore them... That’s “Da real fragmentation” and it makes development much more difficult. In addition, if you have background processes running, your life becomes a nightmare!

In this session we will talk about the problems that we found along the way creating an app which needs to keep track of sensor signals in background. We will review how to deal with the different versions of alarms in Android, how to live with Doze mode and other battery optimization apps and we will show you some hardware and software peculiarities of different manufacturers.

Apart from that, we will explain how we have solved such fragmentation issues in order to develop an app that works properly in as many devices as possible.

Da Real Fragmentation series
Alarms: http://pguardiola.com/blog/darealfragmentation-alarms/
Doze: http://pguardiola.com/blog/darealfragmentation-doze/
Sensors: http://pguardiola.com/blog/darealfragmentation-sensors/
Repository: https://github.com/Guardiola31337/darealfragmentation

Transcript

1. DA REAL FRAGMENTATION EXPLAINED
2. HELLO! Pablo Guardiola @Guardiola31337 Raúl Román @rromanl
4. ALARMS
5. ∎ postDelayed() ∎ AlarmManager ∎ JobScheduler (API 21+) SCHEDULE A TASK
6. ∎ Wake up ∎ Rate (Repeating/One-shot) ∎ Precision (Exact/Inexact) ∎ Clock (Elapsed Real Time/RTC) OPTIONS
7. ∎ set() API 1 ∎ setExact() API 19 ∎ setWindow() API 19 ∎ setRepeating() API 1: Type, trigger time (ms), interval, PendingIntent METHODS
8. ∎ setInexactRepeating() API 3 ∎ setAlarmClock() API 21 ∎ setAndAllowWhileIdle() API 23 ∎ setExactAndAllowWhileIdle() API 23 METHODS
9. PROBLEM SDK Fragmentation ∎ A bunch of APIs do the same ∎ Names of methods almost identical
10. SOLUTIONS ∎ Master AlarmManager ∎ evernote/android-job
11. PROBLEM <5 minutes repeating alarms NOT ALLOWED
12. Samsung Galaxy J5
14. Alarm Set at mar. ago. 09 13:08:23 CEST 2016 Alarm received at mar. ago. 09 13:15:00 CEST 2016 Alarm received at mar. ago. 09 13:15:00 CEST 2016 Alarm received at mar. ago. 09 13:15:41 CEST 2016 Alarm received at mar. ago. 09 13:20:41 CEST 2016 Alarm received at mar. ago. 09 13:25:40 CEST 2016 Alarm received at mar. ago. 09 13:30:41 CEST 2016 Alarm received at mar. ago. 09 13:30:41 CEST 2016 Alarm received at mar. ago. 09 13:35:41 CEST 2016 Xiaomi Redmi Note 2
15. SOLUTIONS ∎ One-shot alarms ∎ setAlarmClock() ∎ Malfunctioning alarms detectors ∎ Sticky services
16. SENSORS
17. CATEGORIES ∎ Motion ∎ Environmental ∎ Position
18. TYPES ∎ Hardware-based ∎ Software-based
19. FRAMEWORK SensorManager ∎ Instance sensor service ∎ Access and list sensors ∎ Register/Unregister listeners ∎ Data acquisition rates ∎ Sensor accuracy constants ∎ Acquire orientation
20. FRAMEWORK SensorEventListener ∎ onSensorChanged() ∎ onAccuracyChanged()
21. FRAMEWORK SensorEvent ∎ Raw sensor data (values) ∎ Type of sensor ∎ Accuracy ∎ Timestamp
22. BATCHING API 19+ Batch period (maxReportLatencyUs)
23. PROBLEM Delay you specify is only a SUGGESTED delay
24. PROBLEM Samples NEVER evenly spaced
25. Huawei P7
26. Bq Aquaris E5
28. SOLUTION LOWER / HIGHER frequency
29. SOLUTION RESAMPLER ∎ Interpolator ∎ Extrapolator
30. PROBLEM GARBAGE DATA until sensor become stable
31. Jiayu S3
32. SOLUTION THROW AWAY initial data
33. PROBLEM Common sensors are NON-WAKE-UP
34. Nexus 6
35. SOLUTION Acquire and release WAKELOCKS wisely
36. PROBLEM EPOCH timestamps
37. 1479140553176;1479140553136657000;-0.158000;-0.016000;9.647000 1479140553196;1479140553196627000;0.462000;-1.719000;3.162000 1479140553396;1479140553396613000;-0.179000;-0.006000;9.566000 1479140553596;1479140553596599000;-0.175000;0.002000;9.599000 Epoch (Jiayu S3) 1479140749449;935794384747;0.172383;0.373495;9.155427 1479140749651;935994876413;0.181959;0.335188;9.117120 1479140749850;936195380007;0.153229;0.325611;9.136273 1479140750052;936396651360;0.162806;0.363919;9.097966 Elapsed time (Moto X 2nd Gen.)
39. SOLUTION BASE TIME + difference
40. PROBLEM BACKJUMPS
41. Nexus 5
43. SOLUTION REARRANGE base time of the following samples
44. PROBLEM SIGNAL noise
45. Jiayu S3
46. SOLUTION ADAPTIVE filters
47. PROBLEM OFFSET/Drifting
48. SOLUTION CALIBRATION
49. PROBLEM System will NOT disable sensors AUTOMATICALLY
50. SOLUTION DISABLE sensors you don’t need anymore
51. PROBLEM Sensor COORDINATE SYSTEM based on device NATURAL ORIENTATION
52. SOLUTION ∎ getRotation() ∎ remapCoordinateSystem() ∎ getOrientation() ∎ getRotationMatrix()
53. PROBLEM NOT safe to hold onto SensorEvent past onSensorChanged()
54. SOLUTION COPY values from SensorEvent
55. POWER-SAVING MODES
56. DOZE API 23+ ∎ AlarmManager ∎ JobScheduler ∎ SyncManager ∎ Network ∎ ...
57. DEEP-DOZE Android 6.0+ ∎ Unplugged ∎ Screen off ∎ No motion detected
59. LIGHT-DOZE Android 7.0+ ∎ Unplugged ∎ Screen off ∎ Not necessarily stationary
62. APP STANDBY API 23+ ∎ User not using the app ∎ App not in foreground ∎ No notifications
63. SMART MANAGER (Samsung) ∎ Always optimizing ∎ Optimizing when not used for 3 days ∎ Turn off
64. PROBLEMS ∎ Two battery optimization modes simultaneously ∎ Task killers ∎ Optimized by default
65. SOLUTIONS ∎ Malfunctioning detectors ∎ Persistency ∎ Logs ∎ Whitelist ∎ Prevent the app to enter
66. PROBLEM ALARMS Alarms methods of Android 5.1- when in Doze (Android 6.0+ devices) WON’T work properly
67. Nexus 6 (3 min. repeating alarm)
68. PROBLEM ALARMS Neither setAndAllowWhileIdle() nor setExactAndAllowWhileIdle() can fire more than once per 9 minutes, per app
69. Nexus 6 setAndAllowWhileIdle() (3 min. repeating alarm)
70. SOLUTIONS ∎ setAndAllowWhileIdle() ∎ setExactAndAllowWhileIdle() ∎ setAlarmClock() ∎ Firebase Cloud Messaging
71. SOLUTIONS ∎ Whitelist (Only wakelocks and network) ∎ Foreground services ∎ Hope
72. PROBLEM SENSORS Normally in idle modes you WON’T receive samples
73. SOLUTIONS ∎ Detect real frequency and increase it: □ Reregistering □ Preventing idle mode
74. CONCLUSIONS ∎ EXPECT THE UNEXPECTED! ∎ FRAGMENTATION IS A FACT ∎ DEFENSIVE CODE
76. THANKS! Any questions?
77. References ∎ Da Real Fragmentation series (http://pguardiola.com) ∎ Da Real Fragmentation GitHub repository (https://github.com/Guardiola31337/darealfragmentation) ∎ Presentation template by SlidesCarnival