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Schedule jobs intelligently

Modern apps can perform many of their tasks asynchronously, outside the direct flow of user interaction. Some examples of these asynchronous tasks are:

  • Updating network resources.
  • Downloading information.
  • Updating background tasks.
  • Scheduling system service calls.

Scheduling this work intelligently can improve your app’s performance, along with aspects of system health such as battery life. JobScheduler does this scheduling work for you.

There are several APIs that your app can use to schedule background work. Chief among these options is JobScheduler. The JobScheduler API allows you to specify robust conditions for executing tasks, along with centralized task scheduling across the device for optimal system health. JobScheduler also offers highly scalable functionality: it is suitable for small tasks like clearing a cache, and for large ones such as syncing a database to the cloud.

In addition to JobScheduler, there are several other facilities available to help your app schedule work. These include:

Note: WorkManager is a new API, currently in alpha, that allows you to schedule background tasks that need guaranteed completion (regardless of whether the app process is around or not). WorkManager provides JobScheduler-like capabilities to API 14+ devices, even those without Google Play Services. WorkManager is queryable (observable), has strong support for graphs of work, and a fluent API. If you are using JobScheduler, FireBaseJobScheduler, and/or AlarmManager plus BroadcastReceivers, you should consider using WorkManager instead. To learn more, see Work Manager.

This page provides brief introductions to JobScheduler and other APIs that can help your app schedule work to maximize app performance and system health. To see an example of the APIs in use, navigate to the Android JobScheduler Sample on GitHub.

Android Framework JobScheduler

JobScheduler is the Android framework API for scheduling tasks or work. It first became available in Android 5.0 (API level 21), and remains under active development. Notably, Android 7.0 (API level 24) added the ability to trigger jobs based on ContentProvider changes.

JobScheduler is implemented in the platform, which allows it to collect information about jobs that need to run across all apps. This information is used to schedule jobs to run at, or around, the same time. Batching job execution in this fashion allows the device to enter and stay in sleep states longer, preserving battery life.

You use JobScheduler by registering jobs, specifying their requirements for network and timing. The system then gracefully schedules the jobs to execute at the appropriate times. At the same time, it also defers job execution as necessary to comply with Doze and App Standby restrictions. JobScheduler provides many methods to define job-execution conditions.

If your app targets Android 5.0 (API level 21), we recommend that you use the JobScheduler to execute background tasks. For more information about JobScheduler, see its API-reference documentation.

AlarmManager

The AlarmManager API is another option that the framework provides for scheduling tasks. This API is useful in cases in which an app needs to post a notification or set off an alarm at a very specific time.

You should only use this API for tasks that must execute at a specific time, but don't require the other, more robust, execution conditions that JobScheduler allows you to specify, such as device idle and charging detect.

Firebase JobDispatcher

Firebase JobDispatcher is an open-source library that provides an API similar to JobScheduler in the Android platform. Firebase JobDispatcher serves as a JobScheduler-compatibility layer for apps targeting versions of Android lower than 5.0 (API level 21).

Firebase JobDispatcher supports the use of Google Play services as an implementation for dispatching (running) jobs, but the library also allows you to define and use other implementations: For example, you might decide to use JobScheduler or write your own, custom code. Because of this versatility, we recommend that you use this Firebase JobDispatcher if your app targets a version of Android lower than 5.0 (API level 21).

For more information about Firebase JobDispatcher, refer to its documentation and source code.

Additional facilities

In addition to the APIs and libraries described above, there are also sync adapters and services that can enable your app, under specific conditions, to perform better and more robustly.

SyncAdapter

The framework continues to provide the SyncAdapter class for managing tasks that sync data between the device and a server. Sync adapters are designed specifically for syncing data between a device and the cloud; you should only use them for this type of task. Sync adapters are more complex to implement than the libraries and APIs mentioned above, because they require at least a fake authenticator and content provider implementation. For these reasons, you typically should not create a sync adapter just to sync data to the cloud in the background. Wherever possible, you should instead use JobScheduler, Firebase JobDispatcher, or GCM Network Manager .

In Android N (API level 24), the SyncManager sits on top of the JobScheduler. You should only use the SyncAdapter class if you require the additional functionality that it provides.

Services

The Services framework allows you to perform long-running operations in the background. We recommend foreground services for tasks, such as playing music, which need to stay resident for the user. Bound services also continue to be useful for various use cases: for example, when a service needs to run only when a user is viewing a fragment or activity.

You should avoid using started services that run perpetually or perform periodic work, since they continue to use device resources even when they aren't performing useful tasks. Instead, you should use other solutions that this page describes, and that provide native lifecycle management. Use started services only as a last resort. The Android platform may not support started services in the future.

Best practices

Regardless of the solution you adopt, keep the following points in mind:

  • Captive Internet Portals, VPNs, and proxies can pose Internet-connectivity detection problems. A library or API may think the Internet is available, but your service may not be accessible. Fail gracefully and reschedule as few of your tasks as possible.
  • Depending on the conditions you assign for running a task, such as network availability, after the task is triggered, a change may occur so that those conditions are no longer met. In such a case, your operation may fail unexpectedly and repeatedly. For this reason, you should code your background task logic to notice when tasks are failing persistently, and perform exponential back-off to avoid inadvertently over-using resources.
  • Remember to use exponential backoff when rescheduling any work, especially when using AlarmManager. If your app uses JobScheduler, Firebase JobDispatcher, or sync adapters, exponential backoff is automatically used.