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android / platform / development / refs/heads/main / . / samples / ApiDemos / src / com / example / android / apis / app / MessengerService.java
blob: f25af9154b499a0159641a4cd5d7e0609231bed4 [file] [log] [blame]
Dianne Hackbornbae0f4f2010-02-16 17:48:27 -0800[diff] [blame]1/*
2 * Copyright (C) 2010 The Android Open Source Project
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
17package com.example.android.apis.app;
18
19import android.app.Notification;
20import android.app.NotificationManager;
21import android.app.PendingIntent;
22import android.app.Service;
23import android.content.Intent;
24import android.os.Binder;
25import android.os.Handler;
26import android.os.IBinder;
27import android.os.Message;
28import android.os.Messenger;
29import android.os.RemoteException;
30import android.util.Log;
31import android.widget.Toast;
32
33import java.util.ArrayList;
34
35// Need the following import to get access to the app resources, since this
36// class is in a sub-package.
37import com.example.android.apis.R;
38import com.example.android.apis.app.RemoteService.Controller;
39
40/**
41 * This is an example of implementing an application service that uses the
42 * {@link Messenger} class for communicating with clients. This allows for
43 * remote interaction with a service, without needing to define an AIDL
44 * interface.
45 *
46 * <p>Notice the use of the {@link NotificationManager} when interesting things
47 * happen in the service. This is generally how background services should
48 * interact with the user, rather than doing something more disruptive such as
49 * calling startActivity().
50 */
51//BEGIN_INCLUDE(service)
52public class MessengerService extends Service {
53 /** For showing and hiding our notification. */
54 NotificationManager mNM;
55 /** Keeps track of all current registered clients. */
56 ArrayList<Messenger> mClients = new ArrayList<Messenger>();
57 /** Holds last value set by a client. */
58 int mValue = 0;
59
60 /**
61 * Command to the service to register a client, receiving callbacks
62 * from the service. The Message's replyTo field must be a Messenger of
63 * the client where callbacks should be sent.
64 */
65 static final int MSG_REGISTER_CLIENT = 1;
66
67 /**
68 * Command to the service to unregister a client, ot stop receiving callbacks
69 * from the service. The Message's replyTo field must be a Messenger of
70 * the client as previously given with MSG_REGISTER_CLIENT.
71 */
72 static final int MSG_UNREGISTER_CLIENT = 2;
73
74 /**
75 * Command to service to set a new value. This can be sent to the
76 * service to supply a new value, and will be sent by the service to
77 * any registered clients with the new value.
78 */
79 static final int MSG_SET_VALUE = 3;
80
81 /**
82 * Handler of incoming messages from clients.
83 */
84 class IncomingHandler extends Handler {
85 @Override
86 public void handleMessage(Message msg) {
87 switch (msg.what) {
88 case MSG_REGISTER_CLIENT:
89 mClients.add(msg.replyTo);
90 break;
91 case MSG_UNREGISTER_CLIENT:
92 mClients.remove(msg.replyTo);
93 break;
94 case MSG_SET_VALUE:
95 mValue = msg.arg1;
96 for (int i=mClients.size()-1; i>=0; i--) {
97 try {
98 mClients.get(i).send(Message.obtain(null,
99 MSG_SET_VALUE, mValue, 0));
100 } catch (RemoteException e) {
101 // The client is dead. Remove it from the list;
102 // we are going through the list from back to front
103 // so this is safe to do inside the loop.
104 mClients.remove(i);
105 }
106 }
107 break;
108 default:
109 super.handleMessage(msg);
110 }
111 }
112 }
113
114 /**
115 * Target we publish for clients to send messages to IncomingHandler.
116 */
117 final Messenger mMessenger = new Messenger(new IncomingHandler());
118
119 @Override
120 public void onCreate() {
121 mNM = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
122
123 // Display a notification about us starting.
124 showNotification();
125 }
126
127 @Override
128 public void onDestroy() {
129 // Cancel the persistent notification.
130 mNM.cancel(R.string.remote_service_started);
131
132 // Tell the user we stopped.
133 Toast.makeText(this, R.string.remote_service_stopped, Toast.LENGTH_SHORT).show();
134 }
135
136 /**
137 * When binding to the service, we return an interface to our messenger
138 * for sending messages to the service.
139 */
140 @Override
141 public IBinder onBind(Intent intent) {
142 return mMessenger.getBinder();
143 }
144
145 /**
146 * Show a notification while this service is running.
147 */
148 private void showNotification() {
149 // In this sample, we'll use the same text for the ticker and the expanded notification
150 CharSequence text = getText(R.string.remote_service_started);
151
Dianne Hackbornbae0f4f2010-02-16 17:48:27 -0800[diff] [blame]152 // The PendingIntent to launch our activity if the user selects this notification
153 PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
154 new Intent(this, Controller.class), 0);
155
156 // Set the info for the views that show in the notification panel.
Chris Wrenb6ba3c52015-06-11 10:56:59 -0400[diff] [blame]157 Notification notification = new Notification.Builder(this)
158 .setSmallIcon(R.drawable.stat_sample) // the status icon
159 .setTicker(text) // the status text
160 .setWhen(System.currentTimeMillis()) // the time stamp
161 .setContentTitle(getText(R.string.local_service_label)) // the label of the entry
162 .setContentText(text) // the contents of the entry
163 .setContentIntent(contentIntent) // The intent to send when the entry is clicked
164 .build();
Dianne Hackbornbae0f4f2010-02-16 17:48:27 -0800[diff] [blame]165
166 // Send the notification.
167 // We use a string id because it is a unique number. We use it later to cancel.
168 mNM.notify(R.string.remote_service_started, notification);
169 }
170}
171//END_INCLUDE(service)