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      1 /*
      2  * Copyright 2014 Google Inc.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.jobscheduler.service;
     18 
     19 import android.app.job.JobParameters;
     20 import android.app.job.JobService;
     21 import android.content.Intent;
     22 import android.os.Handler;
     23 import android.os.Message;
     24 import android.os.Messenger;
     25 import android.os.RemoteException;
     26 import android.support.annotation.Nullable;
     27 import android.util.Log;
     28 
     29 
     30 import static com.example.android.jobscheduler.MainActivity.MESSENGER_INTENT_KEY;
     31 import static com.example.android.jobscheduler.MainActivity.MSG_COLOR_START;
     32 import static com.example.android.jobscheduler.MainActivity.MSG_COLOR_STOP;
     33 import static com.example.android.jobscheduler.MainActivity.WORK_DURATION_KEY;
     34 
     35 
     36 /**
     37  * Service to handle callbacks from the JobScheduler. Requests scheduled with the JobScheduler
     38  * ultimately land on this service's "onStartJob" method. It runs jobs for a specific amount of time
     39  * and finishes them. It keeps the activity updated with changes via a Messenger.
     40  */
     41 public class MyJobService extends JobService {
     42 
     43     private static final String TAG = MyJobService.class.getSimpleName();
     44 
     45     private Messenger mActivityMessenger;
     46 
     47     @Override
     48     public void onCreate() {
     49         super.onCreate();
     50         Log.i(TAG, "Service created");
     51     }
     52 
     53     @Override
     54     public void onDestroy() {
     55         super.onDestroy();
     56         Log.i(TAG, "Service destroyed");
     57     }
     58 
     59     /**
     60      * When the app's MainActivity is created, it starts this service. This is so that the
     61      * activity and this service can communicate back and forth. See "setUiCallback()"
     62      */
     63     @Override
     64     public int onStartCommand(Intent intent, int flags, int startId) {
     65         mActivityMessenger = intent.getParcelableExtra(MESSENGER_INTENT_KEY);
     66         return START_NOT_STICKY;
     67     }
     68 
     69     @Override
     70     public boolean onStartJob(final JobParameters params) {
     71         // The work that this service "does" is simply wait for a certain duration and finish
     72         // the job (on another thread).
     73 
     74         sendMessage(MSG_COLOR_START, params.getJobId());
     75 
     76         long duration = params.getExtras().getLong(WORK_DURATION_KEY);
     77 
     78         // Uses a handler to delay the execution of jobFinished().
     79         Handler handler = new Handler();
     80         handler.postDelayed(new Runnable() {
     81             @Override
     82             public void run() {
     83                 sendMessage(MSG_COLOR_STOP, params.getJobId());
     84                 jobFinished(params, false);
     85             }
     86         }, duration);
     87         Log.i(TAG, "on start job: " + params.getJobId());
     88 
     89         // Return true as there's more work to be done with this job.
     90         return true;
     91     }
     92 
     93     @Override
     94     public boolean onStopJob(JobParameters params) {
     95         // Stop tracking these job parameters, as we've 'finished' executing.
     96         sendMessage(MSG_COLOR_STOP, params.getJobId());
     97         Log.i(TAG, "on stop job: " + params.getJobId());
     98 
     99         // Return false to drop the job.
    100         return false;
    101     }
    102 
    103     private void sendMessage(int messageID, @Nullable Object params) {
    104         // If this service is launched by the JobScheduler, there's no callback Messenger. It
    105         // only exists when the MainActivity calls startService() with the callback in the Intent.
    106         if (mActivityMessenger == null) {
    107             Log.d(TAG, "Service is bound, not started. There's no callback to send a message to.");
    108             return;
    109         }
    110         Message m = Message.obtain();
    111         m.what = messageID;
    112         m.obj = params;
    113         try {
    114             mActivityMessenger.send(m);
    115         } catch (RemoteException e) {
    116             Log.e(TAG, "Error passing service object back to activity.");
    117         }
    118     }
    119 }
    120