How to get the IP address of a peer device in Android for WiFi-Direct (WiFi-P2P)?

Question

I am trying to implement WiFi-Direct(WiFi-P2P) in Android. I refer to the sample code in samples\android-19\legacy\WiFiDirectDemo .

I install WiFiDirectDemo.apk on phone-A and run it. phone-B enable WiFi-Direct(WiFi-P2P) in Android Setting .

After phone-A connect to phone-B , it will show the following information about phone-A .

And the code is as follows:

 @Override public void onConnectionInfoAvailable(final WifiP2pInfo info) { Log.d(WifiP2P.TAG, "onConnectionInfoAvailable----------- " + info); if (progressDialog != null && progressDialog.isShowing()) { progressDialog.dismiss(); } this.info = info; this.getView().setVisibility(View.VISIBLE); // The owner IP is now known. TextView view = (TextView) mContentView.findViewById(R.id.group_owner); view.setText(getResources().getString(R.string.group_owner_text) + ((info.isGroupOwner == true) ? getResources().getString(R.string.yes) : getResources().getString(R.string.no))); // InetAddress from WifiP2pInfo struct. view = (TextView) mContentView.findViewById(R.id.device_info); view.setText("Group Owner IP - " + info.groupOwnerAddress.getHostAddress()); // After the group negotiation, we assign the group owner as the file // server. The file server is single threaded, single connection server // socket. if (info.groupFormed && info.isGroupOwner) { new FileServerAsyncTask(getActivity(), mContentView.findViewById(R.id.status_text)) .execute(); } else if (info.groupFormed) { // The other device acts as the client. In this case, we enable the // get file button. mContentView.findViewById(R.id.btn_start_client).setVisibility(View.VISIBLE); ((TextView) mContentView.findViewById(R.id.status_text)).setText(getResources() .getString(R.string.client_text)); } // hide the connect button mContentView.findViewById(R.id.btn_connect).setVisibility(View.GONE); } 

phone-A - Group Owner . And I want to send TCP data from phone-A to phone-B .

1. How to get the IP address of phone-B .

2. Group Owner IP value means IP address of phone-A

Answer 1

2, Yes, this is the IP address of Phone-A.

1, using this address, Phone-B can send a message to Phone-A. On Phone-A, you can read the IP address of the sender (Phone-B) from the slot after Phone-A received the message “Phone-B”.

Answer 2

To get the IP address, you must use the following method.

  public static String getIpAddress() { try { List<NetworkInterface> interfaces = Collections .list(NetworkInterface.getNetworkInterfaces()); /* * for (NetworkInterface networkInterface : interfaces) { Log.v(TAG, * "interface name " + networkInterface.getName() + "mac = " + * getMACAddress(networkInterface.getName())); } */ for (NetworkInterface intf : interfaces) { if (!getMACAddress(intf.getName()).equalsIgnoreCase( Globals.thisDeviceAddress)) { // Log.v(TAG, "ignore the interface " + intf.getName()); // continue; } if (!intf.getName().contains("p2p")) continue; Log.v(TAG, intf.getName() + " " + getMACAddress(intf.getName())); List<InetAddress> addrs = Collections.list(intf .getInetAddresses()); for (InetAddress addr : addrs) { // Log.v(TAG, "inside"); if (!addr.isLoopbackAddress()) { // Log.v(TAG, "isnt loopback"); String sAddr = addr.getHostAddress().toUpperCase(); Log.v(TAG, "ip=" + sAddr); boolean isIPv4 = InetAddressUtils.isIPv4Address(sAddr); if (isIPv4) { if (sAddr.contains("192.168.49.")) { Log.v(TAG, "ip = " + sAddr); return sAddr; } } } } } } catch (Exception ex) { Log.v(TAG, "error in parsing"); } // for now eat exceptions Log.v(TAG, "returning empty ip address"); return ""; } public static String getMACAddress(String interfaceName) { try { List<NetworkInterface> interfaces = Collections .list(NetworkInterface.getNetworkInterfaces()); for (NetworkInterface intf : interfaces) { if (interfaceName != null) { if (!intf.getName().equalsIgnoreCase(interfaceName)) continue; } byte[] mac = intf.getHardwareAddress(); if (mac == null) return ""; StringBuilder buf = new StringBuilder(); for (int idx = 0; idx < mac.length; idx++) buf.append(String.format("%02X:", mac[idx])); if (buf.length() > 0) buf.deleteCharAt(buf.length() - 1); return buf.toString(); } } catch (Exception ex) { } // for now eat exceptions return ""; /* * try { // this is so Linux hack return * loadFileAsString("/sys/class/net/" +interfaceName + * "/address").toUpperCase().trim(); } catch (IOException ex) { return * null; } */ }