Scheduling Work With WorkManager In Android

Introduction

 

WorkManager has the ability to choose an appropriate way to perform the scheduled task. Choosing the appropriate way means it can decide whether a task should be performed on the thread of our application’s processor using AlarmManager, JobScheduler, Firebase or JobDispatcher. Yes, this is the great feature of WorkManager. If our application is not running at the API level of the device, the included dependencies are the factor to decide how jobs should be scheduled.

 

Adding WorkManager in Project

 

To add WorkManager in a project, specify the below dependency in module level build.gradle file.

dependencies {
implementation "android.arch.work:work-runtime:1.0.0-beta02"
}

This API is in beta so it may have a bug while executing or scheduling the tasks. WorkManager uses different classes to schedule a job, we need to use a subclass of one of them.

 

Worker

 

The worker is an abstract class that extends another abstract class ListenableWorker. ListenableWorker class can perform work asynchronously in WorkManager.

 

Worker class can perform work synchronously on a background thread provided by WorkManager. When we extend the Worker class, we need to override doWork() method in the class. The system instantiates Worker class at runtime and doWork() method is called on the specified background thread.

 

This method is for synchronous processing of the work, if you want asynchronous processing, ListenableWorker is recommended. A Worker is given a maximum of ten minutes to finish its execution and return a ListenableWorker.Result. After this time has expired, the Worker will be signaled to stop.

 

WorkRequest

 

WorkRequest is an abstract class that is used to specify necessary parameters for work that should be queued in WorkManager. We can specify the Worker class where we have written the code to perform the work, the time interval to do periodic tasks, certain conditions or constraints which are required to perform the task.

 

WorkRequest.Builder

 

This is a helper class for creating WorkRequest object. We can use OneTimeWorkRequest.Builder or PeriodicWorkRequest.Builder to perform one-time work or periodic work.

 

Scheduling One Time Work

 

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OneTimeWorkRequest compressionWork =
       new OneTimeWorkRequest.Builder(MyWorker.class)
               .build();
WorkManager.getInstance().enqueue(compressionWork);

Scheduling Periodic Task

 

To perform periodic tasks like syncing data, you can use PeriodicWorkRequest.Builder and PeriodicWorkRequest object for scheduling the task. You can specify time and units in PeriodicWorkRequest.Builder(), but you cannot have an interval less than 15 minutes. It would not show any error but your task will not be performed in case of interval less than 15 minutes.

PeriodicWorkRequest.Builder builder = new PeriodicWorkRequest.Builder(MyWorker.class, 15, TimeUnit.MINUTES);
builder.setConstraints(Constraints.NONE);
PeriodicWorkRequest workRequest = builder.build();
WorkManager.getInstance().enqueue(workRequest);

Cancelling Periodic Work

 

You can cancel a scheduled task by using cancelWorkById(UUID workId) method of WorkManager. You can get Id of scheduled work by WorkRequest object.

UUID workId = workRequest.getId();

WorkManager.getInstance().cancelWorkById(workId);

Example

 

I have created a basic demo application to schedule a one-time task and periodic task. The demo contains a worker class called MyWorker and an Activity to schedule them.

 

MyWorker class

public class MyWorker extends Worker {
   public final String TAG = MyWorker.class.getSimpleName();

   public MyWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
       super(context, workerParams);
   }

   @NonNull
   @Override
   public Result doWork() {
       Log.v(TAG, "Work is in progress");

       try {
           Thread.sleep(1000);
       } catch (InterruptedException e) {
           e.printStackTrace();
       }
       Log.v(TAG, "Work finished");
       return Worker.Result.success();
   }
}

WorkManagerDemoActivity class

public class WorkManagerDemoActivity extends AppCompatActivity {

   private boolean mIsPeriodicWorkScheduled = false;
   private Button mPeriodicWorkButton;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_work_manager_demo);

       mPeriodicWorkButton = findViewById(R.id.button_schedule_periodic_work);
       // One time work
       findViewById(R.id.button_schedule_one_time).setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               OneTimeWorkRequest compressionWork =
                       new OneTimeWorkRequest.Builder(MyWorker.class)
                               .build();
               WorkManager.getInstance().enqueue(compressionWork);

           }
       });

       // Periodic work
       mPeriodicWorkButton.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {

               PeriodicWorkRequest.Builder builder = new PeriodicWorkRequest.Builder(MyWorker.class, 15, TimeUnit.MINUTES);
               builder.setConstraints(Constraints.NONE);
               PeriodicWorkRequest workRequest = builder.build();

               if (mIsPeriodicWorkScheduled) {

                   UUID workId = workRequest.getId();

                   WorkManager.getInstance().cancelWorkById(workId);

                   mPeriodicWorkButton.setText("Schedule Periodic Work");

                   mIsPeriodicWorkScheduled = false;

               } else {

                   WorkManager.getInstance().enqueue(workRequest);

                   mIsPeriodicWorkScheduled = true;

                   mPeriodicWorkButton.setText("Cancel Periodic Work");
               }
           }
       });
   }
}

Layout of Activity

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:gravity="center_horizontal"
   android:orientation="vertical"
   android:padding="20dp"
   tools:context="com.example.atiwari.beprepare.work_manager.WorkManagerDemoActivity">

   <Button
       android:id="@+id/button_schedule_one_time"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="Schedule One Time Work" />

   <Button
       android:id="@+id/button_schedule_periodic_work"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="Schedule Periodic Work" />
</LinearLayout>

If you have any issue while implementing this, please write me in the comment section.

 

Thank you.