A hard-fought road to JobScheduler and back

By November 2018 we'll have to switch to targetSdk 26+, which means almost every app, whether explicitly or not, will use platform JobScheduler. However, this component is far away from being perfect, as it has lots of problems you don’t expect or probably wouldn’t even face till the component reaches the users. In this talk, we’ll discuss such problems, as well as mistakes in Android code, and see how we can switch to JobScheduler as painless as possible.

Transcript

8. Постоянная нагрузка
10. Network BroadcastReceiver <receiver android:name=".MyNetworkReceiver"> <intent-filter> <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/> <action android:name="android.net.wifi.WIFI_STATE_CHANGED"/> <action android:name="android.net.wifi.STATE_CHANGE" /> </intent-filter> </receiver>
13. JobScheduler API
14. Android O – фоновая работа не пройдет 
15. Android O – фоновая работа не пройдет 
16. Это все ради
17. Зачем знать про JobScheduler?
20. Планируем новую задачу JobInfo jobInfo = new JobInfo.Builder( SAMPLE_JOB_ID, SampleJobService.getComponentName() ) .setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED) //... .build();
21. Планируем новую задачу JobInfo jobInfo = new JobInfo.Builder( SAMPLE_JOB_ID, SampleJobService.getComponentName() ) .setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED) //... .build(); JobScheduler jobScheduler = (JobScheduler) getSystemService(JOB_SCHEDULER_SERVICE); jobScheduler.schedule(jobInfo);
22. Периодичность JobInfo jobInfo = //... .setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED) .setRequiresCharging(true) .setPeriodic(10_000) //... .build();
23. Периодичность
24. Сейчас! JobInfo jobInfo = //... .setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED) .setOverrideDeadline(0) //... .build();
29. JobScheduler перезаписывает задачи JobInfo jobInfo = //... .setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY) .setMinimumLatency(TimeUnit.DAYS.toMillis(1)) //... .build(); JobScheduler jobScheduler = (JobScheduler) getSystemService(JOB_SCHEDULER_SERVICE); jobScheduler.schedule(jobInfo);
30. Можно проверять List<JobInfo> pendingJobs = jobScheduler.getAllPendingJobs(); for (JobInfo pendingJob : pendingJobs) { if (pendingJob.getId() == SAMPLE_JOB_ID) { return; } } jobScheduler.schedule(jobInfo);
31. При планировании задач
32. Заменить можно не все
33. Переходим на JobService
34. Ох уж эти булевские флаги @Override public boolean onStartJob(JobParameters params) { // ... return false; } @Override public boolean onStopJob(JobParameters params) { return false; }
35. Ох уж эти булевские флаги @Override public boolean onStartJob(JobParameters params) { // ... return false; } @Override public boolean onStopJob(JobParameters params) { return false; }
36. Ох уж эти булевские флаги @Override public boolean onStartJob(JobParameters params) { // ... return false; } @Override public boolean onStopJob(JobParameters params) { return false; }
37. Ох уж эти булевские флаги (2) @Override public boolean onStartJob(JobParameters params) { executorService.execute(() -> { // ... jobFinished(params, false); }); return true; }
38. НИКОГДА не забывайте @Override public boolean onStartJob(JobParameters params) { executorService.execute(() -> { // ... jobFinished(params, false); }); return true; }
39. НИКОГДА не забывайте @Override public boolean onStartJob(JobParameters params) { executorService.execute(() -> { try { // ... } finally { jobFinished(params, false); } }); return true; }
40. Battery Historian
41. Battery Historian
45. Креши в JobScheduler
46. ВСЕГДА может что-то пойти не так @Nullable private static List<JobInfo> getAllPendingJobs(@NonNull JobScheduler jobScheduler) { try { return jobScheduler.getAllPendingJobs(); } catch (Exception e) { // IllegalStateException, IllegalArgumentException, NPE return null; } }
47. Android-Job об этом знает public void cancel(int jobId) { try { getJobScheduler().cancel(jobId); } catch (Exception e) { mCat.e(e); } }
48. При планировании задач
49. Ошибка синхронизации java.lang.NullPointerException: Attempt to invoke virtual method 'int com.android.server.job.controllers.JobStatus.getUid()' on a null object reference at android.os.Parcel.readException(Parcel.java:1546) at android.os.Parcel.readException(Parcel.java:1493) at android.app.job.IJobCallback$Stub$Proxy.jobFinished(IJobCallback.java:167) at android.app.job.JobService$JobHandler.handleMessage(JobService.java:147) at android.os.Handler.dispatchMessage(Handler.java:102)
50. Android 5
51. Android 7+
54. Отчаяние и рефлексия interface IJobCallback { /* * Tell the job manager that the client is done with its execution, so that it can go on to * the next one and stop attributing wakelock time to us etc. */ void jobFinished(int jobId, boolean reschedule); }
55. Что требуется
56. JobIntentService public void onCreate() { super.onCreate(); if (Build.VERSION.SDK_INT >= 26) { mJobImpl = new JobServiceEngineImpl(this); mCompatWorkEnqueuer = null; } else { mJobImpl = null; ComponentName cn = new ComponentName(this, this.getClass()); mCompatWorkEnqueuer = getWorkEnqueuer(this, cn, false, 0); } }
64. Уменьшаем влияние от ресиверов
65. Отключаем ресиверы public static void setReceiverEnabled(@NonNull Context context, @NonNull Class<? extends BroadcastReceiver> receiverClass, boolean enable) { PackageManager pm = context.getPackageManager(); ComponentName component = new ComponentName(context, receiverClass); int enabledFlag = enabled ? PackageManager.COMPONENT_ENABLED_STATE_ENABLED : PackageManager.COMPONENT_ENABLED_STATE_DISABLED; pm.setComponentEnabledSetting(component, enabledFlag, PackageManager.DONT_KILL_APP); }
69. Резюме
70. Ссылки
72. Прозрачная Activity
73. startForegroundService Intent serviceIntent = new Intent(this, ForegroundService.class); startForegroundService(serviceIntent);
74. Я тебя породил, я тебя и убью @Override public int onStartCommand(Intent intent, int flags, int startId) { executorService.execute(() -> { // do some work System.exit(-1); }); return START_NOT_STICKY; }