Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 1 | page.title=Wi-Fi Peer-to-Peer |
Joe Fernandez | 33baa5a | 2013-11-14 11:41:19 -0800 | [diff] [blame] | 2 | page.tags=wireless,WifiP2pManager,Wi-Fi Direct,WiFi Direct,P2P,Wi-Fi P2P,WiFi P2P |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 3 | |
| 4 | @jd:body |
| 5 | |
| 6 | <div id="qv-wrapper"> |
| 7 | <div id="qv"> |
| 8 | <h2>In this document</h2> |
| 9 | |
| 10 | <ol> |
| 11 | <li><a href="#api">API Overview</a></li> |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 12 | <li><a href="#creating-br">Creating a Broadcast Receiver for Wi-Fi P2P Intents</a></li> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 13 | |
| 14 | <li> |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 15 | <a href="#creating-app">Creating a Wi-Fi P2P Application</a> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 16 | |
| 17 | <ol> |
| 18 | <li><a href="#setup">Initial setup</a></li> |
| 19 | |
| 20 | <li><a href="#discovering">Discovering peers</a></li> |
| 21 | |
| 22 | <li><a href="#connecting">Connecting to peers</a></li> |
| 23 | |
| 24 | <li><a href="#transferring">Transferring data</a></li> |
| 25 | </ol> |
| 26 | </li> |
| 27 | </ol> |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 28 | <h2>See also</h2> |
| 29 | <ul> |
| 30 | <li><a href="{@docRoot}training/connect-devices-wirelessly/wifi-direct.html">Creating |
| 31 | P2P Connections with Wi-Fi</a></li> |
| 32 | </ul> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 33 | </div> |
| 34 | </div> |
| 35 | |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 36 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 37 | <p>Wi-Fi peer-to-peer (P2P) allows Android 4.0 (API level 14) or later devices with the appropriate |
| 38 | hardware to connect directly to each other via Wi-Fi without an intermediate access point (Android's |
| 39 | Wi-Fi P2P framework complies with the Wi-Fi Alliance's Wi-Fi Direct™ certification program). |
| 40 | Using these APIs, you can discover and connect to other devices when each device supports Wi-Fi P2P, |
| 41 | then communicate over a speedy connection across distances much longer than a Bluetooth connection. |
| 42 | This is useful for applications that share data among users, such as a multiplayer game or |
| 43 | a photo sharing application.</p> |
| 44 | |
| 45 | <p>The Wi-Fi P2P APIs consist of the following main parts:</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 46 | |
| 47 | <ul> |
| 48 | <li>Methods that allow you to discover, request, and connect to peers are defined |
| 49 | in the {@link android.net.wifi.p2p.WifiP2pManager} class.</li> |
| 50 | |
| 51 | <li>Listeners that allow you to be notified of the success or failure of {@link |
| 52 | android.net.wifi.p2p.WifiP2pManager} method calls. When calling {@link |
| 53 | android.net.wifi.p2p.WifiP2pManager} methods, each method can receive a specific listener |
| 54 | passed in as a parameter.</li> |
| 55 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 56 | <li>Intents that notify you of specific events detected by the Wi-Fi P2P framework, |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 57 | such as a dropped connection or a newly discovered peer.</li> |
| 58 | </ul> |
| 59 | |
| 60 | <p>You often use these three main components of the APIs together. For example, you can |
| 61 | provide a {@link android.net.wifi.p2p.WifiP2pManager.ActionListener} to a call to {@link |
| 62 | android.net.wifi.p2p.WifiP2pManager#discoverPeers discoverPeers()}, so that you can be |
| 63 | notified with the {@link android.net.wifi.p2p.WifiP2pManager.ActionListener#onSuccess |
| 64 | ActionListener.onSuccess()} and {@link android.net.wifi.p2p.WifiP2pManager.ActionListener#onFailure |
| 65 | ActionListener.onFailure()} |
| 66 | methods. A {@link android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_PEERS_CHANGED_ACTION} intent is |
| 67 | also broadcast if the {@link android.net.wifi.p2p.WifiP2pManager#discoverPeers discoverPeers()} |
| 68 | method discovers that the peers list has changed.</p> |
| 69 | |
| 70 | <h2 id="api">API Overview</h2> |
| 71 | |
| 72 | <p>The {@link android.net.wifi.p2p.WifiP2pManager} class provides methods to allow you to interact with |
| 73 | the Wi-Fi hardware on your device to do things like discover and connect to peers. The following actions |
| 74 | are available:</p> |
| 75 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 76 | <p class="table-caption"><strong>Table 1.</strong>Wi-Fi P2P Methods</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 77 | |
| 78 | <table> |
| 79 | <tr> |
| 80 | <th>Method</th> |
| 81 | <th>Description</th> |
| 82 | </tr> |
| 83 | |
| 84 | <tr> |
| 85 | <td>{@link android.net.wifi.p2p.WifiP2pManager#initialize initialize()}</td> |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 86 | <td>Registers the application with the Wi-Fi framework. This must be called before calling any other Wi-Fi P2P method.</td> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 87 | </tr> |
| 88 | |
| 89 | <tr> |
| 90 | <td>{@link android.net.wifi.p2p.WifiP2pManager#connect connect()}</td> |
| 91 | <td>Starts a peer-to-peer connection with a device with the specified configuration.</td> |
| 92 | </tr> |
| 93 | |
| 94 | <tr> |
| 95 | <td>{@link android.net.wifi.p2p.WifiP2pManager#cancelConnect cancelConnect()}</td> |
| 96 | <td>Cancels any ongoing peer-to-peer group negotiation.</td> |
| 97 | </tr> |
| 98 | |
| 99 | <tr> |
| 100 | <td>{@link android.net.wifi.p2p.WifiP2pManager#requestConnectionInfo requestConnectInfo()}</td> |
| 101 | <td>Requests a device's connection information.</td> |
| 102 | </tr> |
| 103 | |
| 104 | <tr> |
| 105 | <td>{@link android.net.wifi.p2p.WifiP2pManager#createGroup createGroup()}</td> |
| 106 | <td>Creates a peer-to-peer group with the current device as the group owner.</td> |
| 107 | </tr> |
| 108 | |
| 109 | <tr> |
| 110 | <td>{@link android.net.wifi.p2p.WifiP2pManager#removeGroup removeGroup()}</td> |
| 111 | <td>Removes the current peer-to-peer group.</td> |
| 112 | </tr> |
| 113 | |
| 114 | <tr> |
| 115 | <td>{@link android.net.wifi.p2p.WifiP2pManager#requestGroupInfo requestGroupInfo()}</td> |
| 116 | <td>Requests peer-to-peer group information.</td> |
| 117 | </tr> |
| 118 | |
| 119 | <tr> |
| 120 | <td>{@link android.net.wifi.p2p.WifiP2pManager.PeerListListener#discoverPeers discoverPeers()}</td> |
| 121 | <td>Initiates peer discovery </td> |
| 122 | </tr> |
| 123 | |
| 124 | <tr> |
| 125 | <td>{@link android.net.wifi.p2p.WifiP2pManager#requestPeers requestPeers()}</td> |
| 126 | <td>Requests the current list of discovered peers.</td> |
| 127 | </tr> |
| 128 | </table> |
| 129 | |
| 130 | |
| 131 | <p>{@link android.net.wifi.p2p.WifiP2pManager} methods let you pass in a listener, |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 132 | so that the Wi-Fi P2P framework can notify your |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 133 | activity of the status of a call. The available listener interfaces and the |
| 134 | corresponding {@link android.net.wifi.p2p.WifiP2pManager} method calls that use the listeners |
| 135 | are described in the following table:</p> |
| 136 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 137 | <p class="table-caption"><strong>Table 2.</strong> Wi-Fi P2P Listeners</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 138 | |
| 139 | <table> |
| 140 | <tr> |
| 141 | <th>Listener interface</th> |
| 142 | <th>Associated actions</th> |
| 143 | </tr> |
| 144 | <tr> |
| 145 | <td>{@link android.net.wifi.p2p.WifiP2pManager.ActionListener}</td> |
| 146 | <td>{@link android.net.wifi.p2p.WifiP2pManager#connect connect()}, {@link |
| 147 | android.net.wifi.p2p.WifiP2pManager#cancelConnect cancelConnect()}, {@link |
| 148 | android.net.wifi.p2p.WifiP2pManager#createGroup createGroup()}, {@link |
| 149 | android.net.wifi.p2p.WifiP2pManager#removeGroup removeGroup()}, and {@link |
| 150 | android.net.wifi.p2p.WifiP2pManager.PeerListListener#discoverPeers discoverPeers()}</td> |
| 151 | </tr> |
| 152 | |
| 153 | <tr> |
| 154 | <td>{@link android.net.wifi.p2p.WifiP2pManager.ChannelListener}</td> |
| 155 | <td>{@link android.net.wifi.p2p.WifiP2pManager#initialize initialize()}</td> |
| 156 | </tr> |
| 157 | |
| 158 | <tr> |
| 159 | <td>{@link android.net.wifi.p2p.WifiP2pManager.ConnectionInfoListener}</td> |
| 160 | <td>{@link android.net.wifi.p2p.WifiP2pManager#requestConnectionInfo requestConnectInfo()}</td> |
| 161 | </tr> |
| 162 | |
| 163 | <tr> |
| 164 | <td>{@link android.net.wifi.p2p.WifiP2pManager.GroupInfoListener}</td> |
| 165 | <td>{@link android.net.wifi.p2p.WifiP2pManager#requestGroupInfo requestGroupInfo()}</td> |
| 166 | </tr> |
| 167 | |
| 168 | <tr> |
| 169 | <td>{@link android.net.wifi.p2p.WifiP2pManager.PeerListListener}</td> |
| 170 | <td>{@link android.net.wifi.p2p.WifiP2pManager#requestPeers requestPeers()}</td> |
| 171 | </tr> |
| 172 | </table> |
| 173 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 174 | <p>The Wi-Fi P2P APIs define intents that are broadcast when certain Wi-Fi P2P events happen, |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 175 | such as when a new peer is discovered or when a device's Wi-Fi state changes. You can register |
| 176 | to receive these intents in your application by <a href="#creating-br">creating a broadcast |
| 177 | receiver</a> that handles these intents:</p> |
| 178 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 179 | <p class="table-caption"><strong>Table 3.</strong> Wi-Fi P2P Intents</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 180 | |
| 181 | <table> |
| 182 | <tr> |
| 183 | <th>Intent</th> |
| 184 | <th>Description</th> |
| 185 | </tr> |
| 186 | <tr> |
| 187 | <td>{@link android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_CONNECTION_CHANGED_ACTION}</td> |
| 188 | <td>Broadcast when the state of the device's Wi-Fi connection changes.</td> |
| 189 | </tr> |
| 190 | <tr> |
| 191 | <td>{@link android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_PEERS_CHANGED_ACTION}</td> |
| 192 | <td>Broadcast when you call {@link |
| 193 | android.net.wifi.p2p.WifiP2pManager.PeerListListener#discoverPeers discoverPeers()}. You |
| 194 | usually want to call {@link android.net.wifi.p2p.WifiP2pManager.PeerListListener#requestPeers |
| 195 | requestPeers()} to get an updated list of peers if you handle this intent in your |
| 196 | application.</td> |
| 197 | </tr> |
| 198 | <tr> |
| 199 | <td>{@link android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_STATE_CHANGED_ACTION}</td> |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 200 | <td>Broadcast when Wi-Fi P2P is enabled or disabled on the device.</td> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 201 | </tr> |
| 202 | <tr> |
| 203 | <td>{@link android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_THIS_DEVICE_CHANGED_ACTION}</td> |
| 204 | <td>Broadcast when a device's details have changed, such as the device's name.</td> |
| 205 | </tr> |
| 206 | </table> |
| 207 | |
| 208 | |
| 209 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 210 | <h2 id="creating-br">Creating a Broadcast Receiver for Wi-Fi P2P Intents</h2> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 211 | |
| 212 | <p>A broadcast receiver allows you to receive intents broadcast by the Android system, |
| 213 | so that your application can respond to events that you are interested in. The basic steps |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 214 | for creating a broadcast receiver to handle Wi-Fi P2P intents are as follows:</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 215 | |
| 216 | <ol> |
| 217 | <li>Create a class that extends the {@link android.content.BroadcastReceiver} class. For the |
| 218 | class' constructor, you most likely want to have parameters for the {@link |
| 219 | android.net.wifi.p2p.WifiP2pManager}, {@link android.net.wifi.p2p.WifiP2pManager.Channel}, and |
| 220 | the activity that this broadcast receiver will be registered in. This allows the broadcast |
| 221 | receiver to send updates to the activity as well as have access to the Wi-Fi hardware and a |
| 222 | communication channel if needed.</li> |
| 223 | |
| 224 | <li>In the broadcast receiver, check for the intents that you are interested in |
| 225 | <code>{@link android.content.BroadcastReceiver#onReceive onReceive()}</code>. |
| 226 | Carry out any necessary actions depending on the intent that is |
| 227 | received. For example, if the broadcast receiver receives a {@link |
| 228 | android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_PEERS_CHANGED_ACTION} intent, you can call the |
| 229 | {@link android.net.wifi.p2p.WifiP2pManager#requestPeers requestPeers()} method to get a list of |
| 230 | the currently discovered peers.</li> |
| 231 | </ol> |
| 232 | |
| 233 | <p>The following code shows you how to create a typical broadcast receiver. The broadcast |
| 234 | receiver takes a {@link android.net.wifi.p2p.WifiP2pManager} object and an activity as |
| 235 | arguments and uses these two classes to appropriately carry out the needed actions when the |
| 236 | broadcast receiver receives an intent:</p> |
| 237 | |
| 238 | <pre> |
| 239 | /** |
| 240 | * A BroadcastReceiver that notifies of important Wi-Fi p2p events. |
| 241 | */ |
| 242 | public class WiFiDirectBroadcastReceiver extends BroadcastReceiver { |
| 243 | |
Scott Main | 6aad995 | 2013-01-07 18:51:49 -0800 | [diff] [blame] | 244 | private WifiP2pManager mManager; |
| 245 | private Channel mChannel; |
| 246 | private MyWiFiActivity mActivity; |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 247 | |
| 248 | public WiFiDirectBroadcastReceiver(WifiP2pManager manager, Channel channel, |
| 249 | MyWifiActivity activity) { |
| 250 | super(); |
Scott Main | 6aad995 | 2013-01-07 18:51:49 -0800 | [diff] [blame] | 251 | this.mManager = manager; |
| 252 | this.mChannel = channel; |
| 253 | this.mActivity = activity; |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 254 | } |
| 255 | |
| 256 | @Override |
| 257 | public void onReceive(Context context, Intent intent) { |
| 258 | String action = intent.getAction(); |
| 259 | |
| 260 | if (WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)) { |
| 261 | // Check to see if Wi-Fi is enabled and notify appropriate activity |
| 262 | } else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) { |
| 263 | // Call WifiP2pManager.requestPeers() to get a list of current peers |
| 264 | } else if (WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION.equals(action)) { |
| 265 | // Respond to new connection or disconnections |
| 266 | } else if (WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action)) { |
| 267 | // Respond to this device's wifi state changing |
| 268 | } |
| 269 | } |
| 270 | } |
| 271 | </pre> |
| 272 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 273 | <h2 id="creating-app">Creating a Wi-Fi P2P Application</h2> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 274 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 275 | <p>Creating a Wi-Fi P2P application involves creating and registering a |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 276 | broadcast receiver for your application, discovering peers, connecting to a peer, and |
| 277 | transferring data to a peer. The following sections describe how to do this.</p> |
| 278 | |
| 279 | <h3 id="setup">Initial setup</h3> |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 280 | <p>Before using the Wi-Fi P2P APIs, you must ensure that your application can access |
| 281 | the hardware and that the device supports the Wi-Fi P2P protocol. If Wi-Fi P2P is supported, |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 282 | you can obtain an instance of {@link android.net.wifi.p2p.WifiP2pManager}, create and register |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 283 | your broadcast receiver, and begin using the Wi-Fi P2P APIs.</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 284 | <ol> |
| 285 | <li> |
| 286 | <p>Request permission to use the Wi-Fi hardware on the device and also declare |
| 287 | your application to have the correct minimum SDK version in the Android manifest:</p> |
| 288 | <pre> |
| 289 | <uses-sdk android:minSdkVersion="14" /> |
| 290 | <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" /> |
| 291 | <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" /> |
| 292 | <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" /> |
| 293 | <uses-permission android:name="android.permission.INTERNET" /> |
| 294 | <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> |
| 295 | </pre> |
| 296 | </li> |
| 297 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 298 | <li>Check to see if Wi-Fi P2P is on and supported. A good place to check this is in your |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 299 | broadcast receiver when it receives the {@link |
| 300 | android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_STATE_CHANGED_ACTION} intent. Notify your |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 301 | activity of the Wi-Fi P2P state and react accordingly: |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 302 | <pre> |
| 303 | @Override |
| 304 | public void onReceive(Context context, Intent intent) { |
| 305 | ... |
| 306 | String action = intent.getAction(); |
| 307 | if (WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)) { |
| 308 | int state = intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE, -1); |
| 309 | if (state == WifiP2pManager.WIFI_P2P_STATE_ENABLED) { |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 310 | // Wifi P2P is enabled |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 311 | } else { |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 312 | // Wi-Fi P2P is not enabled |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 313 | } |
| 314 | } |
| 315 | ... |
| 316 | } |
| 317 | </pre> |
| 318 | </li> |
| 319 | |
| 320 | <li>In your activity's {@link android.app.Activity#onCreate onCreate()} method, obtain an instance of {@link |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 321 | android.net.wifi.p2p.WifiP2pManager} and register your application with the Wi-Fi P2P |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 322 | framework by calling {@link android.net.wifi.p2p.WifiP2pManager#initialize initialize()}. This |
| 323 | method returns a {@link android.net.wifi.p2p.WifiP2pManager.Channel}, which is used to connect |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 324 | your application to the Wi-Fi P2P framework. You should also create an instance of your |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 325 | broadcast receiver with the {@link |
| 326 | android.net.wifi.p2p.WifiP2pManager} and {@link android.net.wifi.p2p.WifiP2pManager.Channel} |
| 327 | objects along with a reference to your activity. This allows your broadcast receiver to notify |
| 328 | your activity of interesting events and update it accordingly. It also lets you manipulate the device's |
| 329 | Wi-Fi state if necessary: |
| 330 | <pre> |
| 331 | WifiP2pManager mManager; |
| 332 | Channel mChannel; |
| 333 | BroadcastReceiver mReceiver; |
| 334 | ... |
| 335 | @Override |
| 336 | protected void onCreate(Bundle savedInstanceState){ |
| 337 | ... |
| 338 | mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE); |
| 339 | mChannel = mManager.initialize(this, getMainLooper(), null); |
Scott Main | 6aad995 | 2013-01-07 18:51:49 -0800 | [diff] [blame] | 340 | mReceiver = new WiFiDirectBroadcastReceiver(mManager, mChannel, this); |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 341 | ... |
| 342 | } |
| 343 | </pre> |
| 344 | </li> |
| 345 | |
| 346 | <li>Create an intent filter and add the same intents that your |
| 347 | broadcast receiver checks for: |
| 348 | <pre> |
| 349 | IntentFilter mIntentFilter; |
| 350 | ... |
| 351 | @Override |
| 352 | protected void onCreate(Bundle savedInstanceState){ |
| 353 | ... |
| 354 | mIntentFilter = new IntentFilter(); |
| 355 | mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION); |
| 356 | mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION); |
| 357 | mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION); |
| 358 | mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION); |
| 359 | ... |
| 360 | } |
| 361 | </pre> |
| 362 | </li> |
| 363 | |
| 364 | <li>Register the broadcast receiver in the {@link android.app.Activity#onResume()} method |
| 365 | of your activity and unregister it in the {@link android.app.Activity#onPause()} method of your activity: |
| 366 | <pre> |
| 367 | /* register the broadcast receiver with the intent values to be matched */ |
| 368 | @Override |
| 369 | protected void onResume() { |
| 370 | super.onResume(); |
Scott Main | 8edad6f | 2012-03-09 10:55:50 -0800 | [diff] [blame] | 371 | registerReceiver(mReceiver, mIntentFilter); |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 372 | } |
| 373 | /* unregister the broadcast receiver */ |
| 374 | @Override |
| 375 | protected void onPause() { |
| 376 | super.onPause(); |
Scott Main | 8edad6f | 2012-03-09 10:55:50 -0800 | [diff] [blame] | 377 | unregisterReceiver(mReceiver); |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 378 | } |
| 379 | </pre> |
| 380 | |
| 381 | <p>When you have obtained a {@link android.net.wifi.p2p.WifiP2pManager.Channel} and |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 382 | set up a broadcast receiver, your application can make Wi-Fi P2P method calls and receive |
| 383 | Wi-Fi P2P intents.</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 384 | </li> |
| 385 | |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 386 | <p>You can now implement your application and use the Wi-Fi P2P features by calling the |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 387 | methods in {@link android.net.wifi.p2p.WifiP2pManager}. The next sections describe how to do common actions |
| 388 | such as discovering and connecting to peers.</p> |
| 389 | </ol> |
| 390 | |
| 391 | <h3 id="discovering">Discovering peers</h3> |
| 392 | |
| 393 | <p>To discover peers that are available to connect to, call {@link |
| 394 | android.net.wifi.p2p.WifiP2pManager#discoverPeers discoverPeers()} to detect |
| 395 | available peers that are in range. The call to this function is asynchronous and a success or |
| 396 | failure is communicated to your application with {@link |
| 397 | android.net.wifi.p2p.WifiP2pManager.ActionListener#onSuccess onSuccess()} and {@link |
| 398 | android.net.wifi.p2p.WifiP2pManager.ActionListener#onFailure onFailure()} if you created a |
| 399 | {@link android.net.wifi.p2p.WifiP2pManager.ActionListener}. The |
| 400 | {@link android.net.wifi.p2p.WifiP2pManager.ActionListener#onSuccess onSuccess()} method only notifies you |
| 401 | that the discovery process succeeded and does not provide any information about the actual peers |
| 402 | that it discovered, if any:</p> |
| 403 | <pre> |
Scott Main | 6aad995 | 2013-01-07 18:51:49 -0800 | [diff] [blame] | 404 | mManager.discoverPeers(channel, new WifiP2pManager.ActionListener() { |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 405 | @Override |
| 406 | public void onSuccess() { |
| 407 | ... |
| 408 | } |
| 409 | |
| 410 | @Override |
| 411 | public void onFailure(int reasonCode) { |
| 412 | ... |
| 413 | } |
| 414 | }); |
| 415 | |
| 416 | </pre> |
| 417 | |
| 418 | <p>If the discovery process succeeds and detects peers, the system broadcasts the {@link |
| 419 | android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_PEERS_CHANGED_ACTION} intent, which you can listen |
| 420 | for in a broadcast receiver to obtain a list of peers. When your application receives the {@link |
| 421 | android.net.wifi.p2p.WifiP2pManager#WIFI_P2P_PEERS_CHANGED_ACTION} intent, you can request a |
| 422 | list of the discovered peers with {@link |
| 423 | android.net.wifi.p2p.WifiP2pManager#requestPeers requestPeers()}. The following code shows how to set this up:</p> |
| 424 | <pre> |
| 425 | PeerListListener myPeerListListener; |
| 426 | ... |
| 427 | if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) { |
| 428 | |
| 429 | // request available peers from the wifi p2p manager. This is an |
| 430 | // asynchronous call and the calling activity is notified with a |
| 431 | // callback on PeerListListener.onPeersAvailable() |
Scott Main | 6aad995 | 2013-01-07 18:51:49 -0800 | [diff] [blame] | 432 | if (mManager != null) { |
| 433 | mManager.requestPeers(mChannel, myPeerListListener); |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 434 | } |
| 435 | } |
| 436 | </pre> |
| 437 | |
| 438 | <p>The {@link android.net.wifi.p2p.WifiP2pManager#requestPeers requestPeers()} method is also |
| 439 | asynchronous and can notify your activity when a list of peers is available with {@link |
kmccormick | 76dfc02 | 2013-04-03 12:41:12 -0700 | [diff] [blame] | 440 | android.net.wifi.p2p.WifiP2pManager.PeerListListener#onPeersAvailable onPeersAvailable()}, which is defined in |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 441 | the {@link android.net.wifi.p2p.WifiP2pManager.PeerListListener} interface. The {@link |
| 442 | android.net.wifi.p2p.WifiP2pManager.PeerListListener#onPeersAvailable onPeersAvailable()} method |
| 443 | provides you with an {@link android.net.wifi.p2p.WifiP2pDeviceList}, which you can iterate |
| 444 | through to find the peer that you want to connect to.</p> |
| 445 | |
| 446 | <h3 id="connecting">Connecting to peers</h3> |
| 447 | |
| 448 | <p>When you have figured out the device that you want to connect to after obtaining a list of |
| 449 | possible peers, call the {@link android.net.wifi.p2p.WifiP2pManager#connect connect()} method to |
| 450 | connect to the device. This method call requires a {@link android.net.wifi.p2p.WifiP2pConfig} |
| 451 | object that contains the information of the device to connect to. |
| 452 | You can be notified of a connection success or failure through the {@link |
| 453 | android.net.wifi.p2p.WifiP2pManager.ActionListener}. The following code |
| 454 | shows you how to create a connection to a desired device:</p> |
| 455 | <pre> |
| 456 | //obtain a peer from the WifiP2pDeviceList |
| 457 | WifiP2pDevice device; |
| 458 | WifiP2pConfig config = new WifiP2pConfig(); |
| 459 | config.deviceAddress = device.deviceAddress; |
Scott Main | 6aad995 | 2013-01-07 18:51:49 -0800 | [diff] [blame] | 460 | mManager.connect(mChannel, config, new ActionListener() { |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 461 | |
| 462 | @Override |
| 463 | public void onSuccess() { |
| 464 | //success logic |
| 465 | } |
| 466 | |
| 467 | @Override |
| 468 | public void onFailure(int reason) { |
| 469 | //failure logic |
| 470 | } |
| 471 | }); |
| 472 | |
| 473 | </pre> |
| 474 | |
| 475 | |
| 476 | <h3 id="transferring">Transferring data</h3> |
| 477 | <p>Once a connection is established, you can transfer data between the devices with |
| 478 | sockets. The basic steps of transferring data are as follows:</p> |
| 479 | |
| 480 | <ol> |
| 481 | <li>Create a {@link java.net.ServerSocket}. This socket waits for a connection from a client on a specified |
| 482 | port and blocks until it happens, so do this in a background thread.</li> |
| 483 | |
| 484 | <li>Create a client {@link java.net.Socket}. The client uses the IP address and port of |
| 485 | the server socket to connect to the server device.</li> |
| 486 | |
| 487 | <li>Send data from the client to the server. When the client |
| 488 | socket successfully connects to the server socket, you can send data from the client to the server |
| 489 | with byte streams. </li> |
| 490 | |
| 491 | <li>The server socket waits for a client connection (with the {@link java.net.ServerSocket#accept()} method). This |
| 492 | call blocks until a client connects, so call this is another thread. When a connection happens, the server device can receive |
| 493 | the data from the client. Carry out any actions with this data, such as saving it to a file |
| 494 | or presenting it to the user.</li> |
| 495 | </ol> |
| 496 | |
| 497 | <p>The following example, modified from the <a href= |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 498 | "{@docRoot}resources/samples/WiFiDirectDemo/index.html">Wi-Fi P2P Demo</a> sample, shows you how |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 499 | to create this client-server socket communication and transfer JPEG images from a client |
| 500 | to a server with a service. For a complete working example, compile and run the <a href= |
Scott Main | f5e0970 | 2013-08-22 17:19:17 -0700 | [diff] [blame] | 501 | "{@docRoot}resources/samples/WiFiDirectDemo/index.html">Wi-Fi P2P Demo</a> sample.</p> |
Robert Ly | 12a1de0 | 2011-11-02 11:56:50 -0700 | [diff] [blame] | 502 | <pre> |
| 503 | public static class FileServerAsyncTask extends AsyncTask<Void, Void, String> { |
| 504 | |
| 505 | private Context context; |
| 506 | private TextView statusText; |
| 507 | |
| 508 | public FileServerAsyncTask(Context context, View statusText) { |
| 509 | this.context = context; |
| 510 | this.statusText = (TextView) statusText; |
| 511 | } |
| 512 | |
| 513 | @Override |
| 514 | protected String doInBackground(Void... params) { |
| 515 | try { |
| 516 | |
| 517 | /** |
| 518 | * Create a server socket and wait for client connections. This |
| 519 | * call blocks until a connection is accepted from a client |
| 520 | */ |
| 521 | ServerSocket serverSocket = new ServerSocket(8888); |
| 522 | Socket client = serverSocket.accept(); |
| 523 | |
| 524 | /** |
| 525 | * If this code is reached, a client has connected and transferred data |
| 526 | * Save the input stream from the client as a JPEG file |
| 527 | */ |
| 528 | final File f = new File(Environment.getExternalStorageDirectory() + "/" |
| 529 | + context.getPackageName() + "/wifip2pshared-" + System.currentTimeMillis() |
| 530 | + ".jpg"); |
| 531 | |
| 532 | File dirs = new File(f.getParent()); |
| 533 | if (!dirs.exists()) |
| 534 | dirs.mkdirs(); |
| 535 | f.createNewFile(); |
| 536 | InputStream inputstream = client.getInputStream(); |
| 537 | copyFile(inputstream, new FileOutputStream(f)); |
| 538 | serverSocket.close(); |
| 539 | return f.getAbsolutePath(); |
| 540 | } catch (IOException e) { |
| 541 | Log.e(WiFiDirectActivity.TAG, e.getMessage()); |
| 542 | return null; |
| 543 | } |
| 544 | } |
| 545 | |
| 546 | /** |
| 547 | * Start activity that can handle the JPEG image |
| 548 | */ |
| 549 | @Override |
| 550 | protected void onPostExecute(String result) { |
| 551 | if (result != null) { |
| 552 | statusText.setText("File copied - " + result); |
| 553 | Intent intent = new Intent(); |
| 554 | intent.setAction(android.content.Intent.ACTION_VIEW); |
| 555 | intent.setDataAndType(Uri.parse("file://" + result), "image/*"); |
| 556 | context.startActivity(intent); |
| 557 | } |
| 558 | } |
| 559 | } |
| 560 | </pre> |
| 561 | |
| 562 | <p>On the client, connect to the server socket with a client socket and transfer data. This example |
| 563 | transfers a JPEG file on the client device's file system.</p> |
| 564 | |
| 565 | <pre> |
| 566 | Context context = this.getApplicationContext(); |
| 567 | String host; |
| 568 | int port; |
| 569 | int len; |
| 570 | Socket socket = new Socket(); |
| 571 | byte buf[] = new byte[1024]; |
| 572 | ... |
| 573 | try { |
| 574 | /** |
| 575 | * Create a client socket with the host, |
| 576 | * port, and timeout information. |
| 577 | */ |
| 578 | socket.bind(null); |
| 579 | socket.connect((new InetSocketAddress(host, port)), 500); |
| 580 | |
| 581 | /** |
| 582 | * Create a byte stream from a JPEG file and pipe it to the output stream |
| 583 | * of the socket. This data will be retrieved by the server device. |
| 584 | */ |
| 585 | OutputStream outputStream = socket.getOutputStream(); |
| 586 | ContentResolver cr = context.getContentResolver(); |
| 587 | InputStream inputStream = null; |
| 588 | inputStream = cr.openInputStream(Uri.parse("path/to/picture.jpg")); |
| 589 | while ((len = inputStream.read(buf)) != -1) { |
| 590 | outputStream.write(buf, 0, len); |
| 591 | } |
| 592 | outputStream.close(); |
| 593 | inputStream.close(); |
| 594 | } catch (FileNotFoundException e) { |
| 595 | //catch logic |
| 596 | } catch (IOException e) { |
| 597 | //catch logic |
| 598 | } |
| 599 | |
| 600 | /** |
| 601 | * Clean up any open sockets when done |
| 602 | * transferring or if an exception occurred. |
| 603 | */ |
| 604 | finally { |
| 605 | if (socket != null) { |
| 606 | if (socket.isConnected()) { |
| 607 | try { |
| 608 | socket.close(); |
| 609 | } catch (IOException e) { |
| 610 | //catch logic |
| 611 | } |
| 612 | } |
| 613 | } |
| 614 | } |
| 615 | </pre> |