Browse Author: Abhishek Waikar

Firebase JobDispatcher

The Firebase JobDispatcher is a library for scheduling background jobs in your Android app. It provides a JobScheduler-compatible API that works on all recent versions of Android (API level 9+) that have Google Play services installed.

Overview

What’s a JobScheduler?

The JobScheduler is an Android system service available on API levels 21 (Lollipop)+. It provides an API for scheduling units of work (represented by JobService subclasses) that will be executed in your app’s process.

Why is this better than background services and listening for system broadcasts?

Running apps in the background is expensive, which is especially harmful when they’re not actively doing work that’s important to the user. That problem is multiplied when those background services are listening for frequently sent broadcasts (android.net.conn.CONNECTIVITY_CHANGE and android.hardware.action.NEW_PICTURE are common examples). Even worse, there’s no way of specifying prerequisites for these broadcasts. Listening for CONNECTIVITY_CHANGE broadcasts does not guarantee that the device has an active network connection, only that the connection was recently changed.

In recognition of these issues, the Android framework team created the JobScheduler. This provides developers a simple way of specifying runtime constraints on their jobs. Available constraints include network typecharging state, and idle state.

This library uses the scheduling engine inside Google Play services(formerly the GCM Network Manager component) to provide a backwards compatible (back to Gingerbread) JobScheduler-like API.

This I/O presentation has more information on why background services can be harmful and what you can do about them:

 

There’s more information on upcoming changes to Android’s approach to background services on the Android developer preview page.

Requirements

The FirebaseJobDispatcher currently relies on the scheduling component in Google Play services. Because of that, it won’t work on environments without Google Play services installed.

Comparison to other libraries

Library Minimum API Requires Google Play Service API1 Custom retry strategies
Framework JobScheduler 21 No JobScheduler Yes
Firebase JobDispatcher 9 Yes JobScheduler Yes
evernote/android-job 14 No2 Custom Yes

1: Refers to the methods that need to be implemented in the Service subclass.
2: Uses AlarmManager to support API levels <= 21 if Google Play services is unavailable.

Getting started

Installation

Add the following to your build.gradle‘s dependencies section:

compile 'com.firebase:firebase-jobdispatcher:0.8.5'

Usage

Writing a new JobService

The simplest possible JobService:

import com.firebase.jobdispatcher.JobParameters;
import com.firebase.jobdispatcher.JobService;

public class MyJobService extends JobService {
    @Override
    public boolean onStartJob(JobParameters job) {
        // Do some work here

        return false; // Answers the question: "Is there still work going on?"
    }

    @Override
    public boolean onStopJob(JobParameters job) {
        return false; // Answers the question: "Should this job be retried?"
    }
}

Adding it to the manifest

<service
    android:exported="false"
    android:name=".MyJobService">
    <intent-filter>
        <action android:name="com.firebase.jobdispatcher.ACTION_EXECUTE"/>
    </intent-filter>
</service>

Creating a Dispatcher

// Create a new dispatcher using the Google Play driver.
FirebaseJobDispatcher dispatcher = new FirebaseJobDispatcher(new GooglePlayDriver(context));

Scheduling a simple job

Job myJob = dispatcher.newJobBuilder()
    .setService(MyJobService.class) // the JobService that will be called
    .setTag("my-unique-tag")        // uniquely identifies the job
    .build();

dispatcher.mustSchedule(myJob);

Scheduling a more complex job

Bundle myExtrasBundle = new Bundle();
myExtrasBundle.putString("some_key", "some_value");

Job myJob = dispatcher.newJobBuilder()
    // the JobService that will be called
    .setService(MyJobService.class)
    // uniquely identifies the job
    .setTag("my-unique-tag")
    // one-off job
    .setRecurring(false)
    // don't persist past a device reboot
    .setLifetime(Lifetime.UNTIL_NEXT_BOOT)
    // start between 0 and 60 seconds from now
    .setTrigger(Trigger.executionWindow(0, 60))
    // don't overwrite an existing job with the same tag
    .setReplaceCurrent(false)
    // retry with exponential backoff
    .setRetryStrategy(RetryStrategy.DEFAULT_EXPONENTIAL)
    // constraints that need to be satisfied for the job to run
    .setConstraints(
        // only run on an unmetered network
        Constraint.ON_UNMETERED_NETWORK,
        // only run when the device is charging
        Constraint.DEVICE_CHARGING
    )
    .setExtras(myExtrasBundle)
    .build();

dispatcher.mustSchedule(myJob);

Cancelling a job

dispatcher.cancel("my-unique-tag");

Cancelling all jobs

dispatcher.cancelAll();

For more info please check this link => https://github.com/firebase/firebase-jobdispatcher-android#user-content-firebase-jobdispatcher-

Reduce friction with the new Location APIs

The new APIs do not require your app to manually manage a connection to Google Play services through a GoogleApiClient. This reduces boilerplate and common pitfalls in your app.

 

A better developer experience

The new LocationServices APIs are much simpler and will make your code less error prone. The connection logic is handled automatically, and you only need to attach a single completion listener:

 

public class MainActivity extends AppCompatActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    FusedLocationProviderClient client =
            LocationServices.getFusedLocationProviderClient(this);

    client.requestLocationUpdates(LocationRequest.create(), pendingIntent)
        .addOnCompleteListener(new OnCompleteListener() {
          @Override
          public void onComplete(@NonNull Task task) {
            Log.d("MainActivity", "Result: " + task.getResult());
          }
        });
  }
}

The new API immediately improves the code in a few ways:

  • The API calls automatically wait for the service connection to be established, which removes the need to wait for onConnected before making requests.
  • It uses the Task API which makes it easier to compose asynchronous operations.
  • The code is self-contained and could easily be moved into a shared utility class or similar.
  • You don’t need to understand the underlying connection process to start coding.

What happened to all of the callbacks?

The new API will automatically resolve certain connection failures for you, so you don’t need to write code that for things like prompting the user to update Google Play services. Rather than exposing connection failures globally in the onConnectionFailed method, connection problems will fail the Task with an ApiException:

client.requestLocationUpdates(LocationRequest.create(), pendingIntent)
        .addOnFailureListener(new OnFailureListener() {
          @Override
          public void onFailure(@NonNull Exception e) {
            if (e instanceof ApiException) {
              Log.w(TAG, ((ApiException) e).getStatusMessage());
            } else {
              Log.w(TAG, e.getMessage());
            }
          }
        });

Read more , or head straight to  https://github.com/googlesamples/android-play-location

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