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
   

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2. HELLO!
   Pablo Guardiola
   @Guardiola31337
   Raúl Román
   @rromanl
   

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3. View Slide

4. ALARMS
   

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5. ∎ postDelayed()
   ∎ AlarmManager
   ∎ JobScheduler (API 21+)
   SCHEDULE A TASK
   

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6. ∎ Wake up
   ∎ Rate (Repeating/One-shot)
   ∎ Precision (Exact/Inexact)
   ∎ Clock (Elapsed Real Time/RTC)
   OPTIONS
   

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7. ∎ set() API 1
   ∎ setExact() API 19
   ∎ setWindow() API 19
   ∎ setRepeating() API 1:
   Type, trigger time (ms), interval,
   PendingIntent
   METHODS
   

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8. ∎ setInexactRepeating() API 3
   ∎ setAlarmClock() API 21
   ∎ setAndAllowWhileIdle() API 23
   ∎ setExactAndAllowWhileIdle() API 23
   METHODS
   

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9. PROBLEM
   SDK Fragmentation
   ∎ A bunch of APIs do the same
   ∎ Names of methods almost
   identical
   

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10. SOLUTIONS
    ∎ Master AlarmManager
    ∎ evernote/android-job
    

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11. PROBLEM
    <5 minutes repeating
    alarms
    NOT ALLOWED
    

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12. Samsung Galaxy J5
    

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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
    

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15. SOLUTIONS
    ∎ One-shot alarms
    ∎ setAlarmClock()
    ∎ Malfunctioning alarms detectors
    ∎ Sticky services
    

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16. SENSORS
    

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17. CATEGORIES
    ∎ Motion
    ∎ Environmental
    ∎ Position
    

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18. TYPES
    ∎ Hardware-based
    ∎ Software-based
    

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19. FRAMEWORK
    SensorManager
    ∎ Instance sensor service
    ∎ Access and list sensors
    ∎ Register/Unregister listeners
    ∎ Data acquisition rates
    ∎ Sensor accuracy constants
    ∎ Acquire orientation
    

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20. FRAMEWORK
    SensorEventListener
    ∎ onSensorChanged()
    ∎ onAccuracyChanged()
    

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21. FRAMEWORK
    SensorEvent
    ∎ Raw sensor data (values)
    ∎ Type of sensor
    ∎ Accuracy
    ∎ Timestamp
    

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22. BATCHING
    API 19+
    Batch period
    (maxReportLatencyUs)
    

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23. PROBLEM
    Delay you specify is
    only a SUGGESTED
    delay
    

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24. PROBLEM
    Samples NEVER
    evenly spaced
    

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25. Huawei P7
    

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26. Bq Aquaris E5
    

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28. SOLUTION
    LOWER / HIGHER
    frequency
    

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29. SOLUTION
    RESAMPLER
    ∎ Interpolator
    ∎ Extrapolator
    

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30. PROBLEM
    GARBAGE DATA until
    sensor become
    stable
    

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31. Jiayu S3
    

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32. SOLUTION
    THROW AWAY
    initial data
    

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33. PROBLEM
    Common sensors
    are NON-WAKE-UP
    

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34. Nexus 6
    

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35. SOLUTION
    Acquire and release
    WAKELOCKS wisely
    

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36. PROBLEM
    EPOCH
    timestamps
    

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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.)
    

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38. View Slide

39. SOLUTION
    BASE TIME +
    difference
    

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40. PROBLEM
    BACKJUMPS
    

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41. Nexus 5
    

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43. SOLUTION
    REARRANGE base
    time of the following
    samples
    

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44. PROBLEM
    SIGNAL noise
    

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45. Jiayu S3
    

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46. SOLUTION
    ADAPTIVE
    filters
    

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47. PROBLEM
    OFFSET/Drifting
    

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48. SOLUTION
    CALIBRATION
    

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49. PROBLEM
    System will NOT disable
    sensors
    AUTOMATICALLY
    

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50. SOLUTION
    DISABLE sensors
    you don’t need
    anymore
    

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51. PROBLEM
    Sensor COORDINATE
    SYSTEM based on device
    NATURAL ORIENTATION
    

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52. SOLUTION
    ∎ getRotation()
    ∎ remapCoordinateSystem()
    ∎ getOrientation()
    ∎ getRotationMatrix()
    

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53. PROBLEM
    NOT safe to hold onto
    SensorEvent past
    onSensorChanged()
    

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54. SOLUTION
    COPY values from
    SensorEvent
    

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55. POWER-SAVING
    MODES
    

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56. DOZE
    API 23+
    ∎ AlarmManager
    ∎ JobScheduler
    ∎ SyncManager
    ∎ Network
    ∎ ...
    

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57. DEEP-DOZE
    Android 6.0+
    ∎ Unplugged
    ∎ Screen off
    ∎ No motion detected
    

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59. LIGHT-DOZE
    Android 7.0+
    ∎ Unplugged
    ∎ Screen off
    ∎ Not necessarily stationary
    

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62. APP STANDBY
    API 23+
    ∎ User not using the app
    ∎ App not in foreground
    ∎ No notifications
    

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63. SMART MANAGER (Samsung)
    ∎ Always optimizing
    ∎ Optimizing when not used
    for 3 days
    ∎ Turn off
    

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64. PROBLEMS
    ∎ Two battery optimization
    modes simultaneously
    ∎ Task killers
    ∎ Optimized by default
    

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65. SOLUTIONS
    ∎ Malfunctioning detectors
    ∎ Persistency
    ∎ Logs
    ∎ Whitelist
    ∎ Prevent the app to enter
    

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66. PROBLEM
    ALARMS
    Alarms methods of Android 5.1-
    when in Doze (Android 6.0+ devices)
    WON’T work properly
    

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67. Nexus 6
    (3 min. repeating alarm)
    

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68. PROBLEM
    ALARMS
    Neither setAndAllowWhileIdle() nor
    setExactAndAllowWhileIdle() can fire
    more than once per 9 minutes, per
    app
    

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69. Nexus 6
    setAndAllowWhileIdle()
    (3 min. repeating alarm)
    

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70. SOLUTIONS
    ∎ setAndAllowWhileIdle()
    ∎ setExactAndAllowWhileIdle()
    ∎ setAlarmClock()
    ∎ Firebase Cloud Messaging
    

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71. SOLUTIONS
    ∎ Whitelist (Only wakelocks
    and network)
    ∎ Foreground services
    ∎ Hope
    

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72. PROBLEM
    SENSORS
    Normally in idle modes you
    WON’T receive samples
    

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73. SOLUTIONS
    ∎ Detect real frequency and
    increase it:
    □ Reregistering
    □ Preventing idle mode
    

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74. CONCLUSIONS
    ∎ EXPECT THE UNEXPECTED!
    ∎ FRAGMENTATION IS A FACT
    ∎ DEFENSIVE CODE
    

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76. THANKS!
    Any questions?
    

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77. References
    ∎ Da Real Fragmentation series (http://pguardiola.com)
    ∎ Da Real Fragmentation GitHub repository
    (https://github.com/Guardiola31337/darealfragmentation)
    ∎ Presentation template by SlidesCarnival
    

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