Android 5.0 internals and inferiority complex droidcon.de 2015
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The document discusses the technical details and updates of Android Lollipop, highlighting the gap between average developers and top developers from Google. It covers new APIs, the emphasis on project advancements such as Project Volta for improved battery life, and job scheduling in Android. The presentation encourages developers to overcome feelings of inferiority and to engage deeply with coding to improve their skills.
![BatteryController
public class ChargingTracker extends BroadcastReceiver {
private final AlarmManager mAlarm;
private final PendingIntent mStableChargingTriggerIntent;
[...]
@Override
public void onReceive(Context context, Intent intent) {
onReceiveInternal(intent);
}
}](https://image.slidesharecdn.com/android5-150605121325-lva1-app6891/85/Android-5-0-internals-and-inferiority-complex-droidcon-de-2015-40-320.jpg)
![public void startTracking() {
IntentFilter filter = new IntentFilter();
// Battery health.
filter.addAction(Intent.ACTION_BATTERY_LOW);
filter.addAction(Intent.ACTION_BATTERY_OKAY);
// Charging/not charging.
filter.addAction(Intent.ACTION_POWER_CONNECTED);
filter.addAction(Intent.ACTION_POWER_DISCONNECTED);
// Charging stable.
filter.addAction(ACTION_CHARGING_STABLE);
mContext.registerReceiver(this, filter);
[...]
}](https://image.slidesharecdn.com/android5-150605121325-lva1-app6891/85/Android-5-0-internals-and-inferiority-complex-droidcon-de-2015-41-320.jpg)
![public void onReceiveInternal(Intent intent) {
final String action = intent.getAction();
if (Intent.ACTION_BATTERY_LOW.equals(action)) {
[...]
mBatteryHealthy = false;
} else if (Intent.ACTION_BATTERY_OKAY.equals(action)) {
[...]
mBatteryHealthy = true;
maybeReportNewChargingState();
}
[...]
}](https://image.slidesharecdn.com/android5-150605121325-lva1-app6891/85/Android-5-0-internals-and-inferiority-complex-droidcon-de-2015-42-320.jpg)
![@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
[...]
} else if (action.equals(Intent.ACTION_SCREEN_OFF)
|| action.equals(Intent.ACTION_DREAMING_STARTED)) {
final long nowElapsed = SystemClock.elapsedRealtime();
final long when = nowElapsed + INACTIVITY_IDLE_THRESHOLD;
mAlarm.setWindow(AlarmManager.ELAPSED_REALTIME_WAKEUP,
when, IDLE_WINDOW_SLOP, mIdleTriggerIntent);
}
[...]](https://image.slidesharecdn.com/android5-150605121325-lva1-app6891/85/Android-5-0-internals-and-inferiority-complex-droidcon-de-2015-63-320.jpg)
![@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(Intent.ACTION_SCREEN_ON)
|| action.equals(Intent.ACTION_DREAMING_STOPPED)) {
// possible transition to not-idle
if (mIdle) {
[...]
mAlarm.cancel(mIdleTriggerIntent);
mIdle = false;
reportNewIdleState(mIdle);
}
[...]](https://image.slidesharecdn.com/android5-150605121325-lva1-app6891/85/Android-5-0-internals-and-inferiority-complex-droidcon-de-2015-64-320.jpg)
![@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
[...]
} else if (action.equals(ACTION_TRIGGER_IDLE)) {
// idle time starts now
if (!mIdle) {
[...]
mIdle = true;
reportNewIdleState(mIdle);
}
}
}](https://image.slidesharecdn.com/android5-150605121325-lva1-app6891/85/Android-5-0-internals-and-inferiority-complex-droidcon-de-2015-65-320.jpg)
Android 5.0 internals and inferiority complex droidcon.de 2015
- 1. Android Lollipop Internals and our inferiority complex or impostor syndrome
- 3. About presentation and the gap between us mortals and rockstar developers from Square and Google
- 4. History ● originally as “What’s new in Lollipop” ● about new APIs ● how it works under the hood ● the devil is in the detail http://nelenkov.blogspot.de/@kapitanpetko
- 5. What to look for ● technical information a bit ● motivation hopefully lot more ● are we rockstar devs or not?
- 6. Disclaimer
- 7. Disclaimer ● nothing against the Google ● actually make a living thanks to their technologies
- 8. Disclaimer ● don’t want to diminish their achievements ● or suggest anything bad about their devs
- 9. Disclaimer ● have never been recruited by them
- 10. The APIs arms race
- 12. The APIs arms race ● each new release thousands new APIs ● iOS 8 includes over 4,000 new APIs ● thousands of new Material Designs or new Bluetooth stacks?
- 13. The APIs arms race ● the more, the better ● … or just a marketing? ● Android Weekly pressure ;-)
- 14. Lollipop Or any other Android version, I guess
- 15. Significant changes ● Material Design ● WebView updated via Play Store ● FDE
- 16. Significant changes ● Bluetooth stack changes ● Android Work/Multi-user - BYOD ● JobScheduler API
- 19. One random change ● new package android.util.Range ● immutable range
- 20. android.util.Range ● check if a value is in a range ● check if ranges are equal ● get lower/upper values ● intersect two ranges
- 21. Range::contains(value) public boolean contains(T value) { checkNotNull(value, "value must not be null"); boolean gteLower = value.compareTo(mLower) >= 0; boolean lteUpper = value.compareTo(mUpper) <= 0; return gteLower && lteUpper; }
- 22. The Projects
- 23. Project Butter ● in JellyBean ● smoother UI 60fps
- 24. Other projects ● Svelte in KitKat running low-end on devices with 512MB or less ● Pi ;-) Google as a telecom
- 25. Project Volta ● improve battery life
- 26. Project Volta ● at platform level ● at developers level ● at users level
- 27. Project Volta ● ART runtime ● JobScheduler API and Battery Historian ● Battery Saver
- 28. JobScheduler API
- 29. Our task Our App Task ● non user-facing background task ;-) ● can wait to be run later execution time doesn’t matter ● resource intensive
- 30. The old way Our App Task Alarm Manager Network Manager Battery Manager
- 31. JobInfo.Builder builder = new JobInfo.Builder(jobId, serviceComponent) .setMinimumLatency(4000) .setOverrideDeadline(5000) .setRequiredNetworkType( JobInfo.NETWORK_TYPE_UNMETERED) .setRequiresCharging(true) .setPersisted(true); JobInfo jobInfo = builder.build(); constraints our task task is now a job
- 33. JobScheduler Our App Job Info JobInfo.Builder schedule() Job Scheduler
- 40. BatteryController public class ChargingTracker extends BroadcastReceiver { private final AlarmManager mAlarm; private final PendingIntent mStableChargingTriggerIntent; [...] @Override public void onReceive(Context context, Intent intent) { onReceiveInternal(intent); } }
- 41. public void startTracking() { IntentFilter filter = new IntentFilter(); // Battery health. filter.addAction(Intent.ACTION_BATTERY_LOW); filter.addAction(Intent.ACTION_BATTERY_OKAY); // Charging/not charging. filter.addAction(Intent.ACTION_POWER_CONNECTED); filter.addAction(Intent.ACTION_POWER_DISCONNECTED); // Charging stable. filter.addAction(ACTION_CHARGING_STABLE); mContext.registerReceiver(this, filter); [...] }
- 42. public void onReceiveInternal(Intent intent) { final String action = intent.getAction(); if (Intent.ACTION_BATTERY_LOW.equals(action)) { [...] mBatteryHealthy = false; } else if (Intent.ACTION_BATTERY_OKAY.equals(action)) { [...] mBatteryHealthy = true; maybeReportNewChargingState(); } [...] }
- 46. GCMNetworkManager Fresh from Google I/O 2015 Cloud Messaging 3.0
- 48. ● based on GPS not API 21 so portable ● tasks vs jobs so similar API ● jobs executed on a service so similar API again ;-) GCMNetworkManager
- 52. Idle mode system has determined that phone is not being used and is not likely to be used anytime soon
- 53. Idle mode example Job criteria: idle state + charging When: at night, when the phone is next to your bed
- 55. Many Googles ● not the same Google for every one of us ● different search results ● different ads ● fine-grained targeting of contents
- 59. Almost there... ● strong technology marketing videos, blog posts, APIs arms race ● bold statements about possibilities idle state, at night, next to the bed ● proven track record search and ads tailored to our behaviour
- 60. The idle state algorithm or is it “idle”?
- 61. // Policy: we decide that we're "idle" if the device has been unused / // screen off or dreaming for at least this long private static final long INACTIVITY_IDLE_THRESHOLD = 71 * 60 * 1000; // millis; 71 min private static final long IDLE_WINDOW_SLOP = 5 * 60 * 1000; // 5 minute window, to be nice quotes are here ;-)
- 62. The “idle” state algorithm 1. display turns off 2. start the timer for 71 minutes +/- 5 minutes 3. alarm goes off 4. if screen still turned off we are in the idle state
- 63. @Override public void onReceive(Context context, Intent intent) { final String action = intent.getAction(); [...] } else if (action.equals(Intent.ACTION_SCREEN_OFF) || action.equals(Intent.ACTION_DREAMING_STARTED)) { final long nowElapsed = SystemClock.elapsedRealtime(); final long when = nowElapsed + INACTIVITY_IDLE_THRESHOLD; mAlarm.setWindow(AlarmManager.ELAPSED_REALTIME_WAKEUP, when, IDLE_WINDOW_SLOP, mIdleTriggerIntent); } [...]
- 64. @Override public void onReceive(Context context, Intent intent) { final String action = intent.getAction(); if (action.equals(Intent.ACTION_SCREEN_ON) || action.equals(Intent.ACTION_DREAMING_STOPPED)) { // possible transition to not-idle if (mIdle) { [...] mAlarm.cancel(mIdleTriggerIntent); mIdle = false; reportNewIdleState(mIdle); } [...]
- 65. @Override public void onReceive(Context context, Intent intent) { final String action = intent.getAction(); [...] } else if (action.equals(ACTION_TRIGGER_IDLE)) { // idle time starts now if (!mIdle) { [...] mIdle = true; reportNewIdleState(mIdle); } } }
- 66. The “idle” state algorithm ● time is not a factor at night ● sensors not used lying next to the bed Android Doze to the rescue?
- 67. The “idle” state algorithm ● display the only factor how long is being turned off ● not tuned per user same for everyone not based on our own behaviour
- 68. The “idle” state algorithm ● random 71 minutes or maybe there is some magic here?
- 69. Takeaways ● don’t be afraid to look at the code not a rocket science there can cure from inferiority complex ● write code to get better it always sucks with the first version gets better which each commit or PR
- 70. Thanks ● droidcon Berlin ● YOU for attending my talk and others too ;-)