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
onCreate()48     public void onCreate() {
49         super.onCreate();
50         Log.i(TAG, "Service created");
51     }
52 
53     @Override
onDestroy()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
onStartCommand(Intent intent, int flags, int startId)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
onStartJob(final JobParameters params)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
onStopJob(JobParameters params)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 
sendMessage(int messageID, @Nullable Object params)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