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

Question

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

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

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

And the code is like the following :

@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);                 
    }

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

1. How do I get the phone-B's IP address. ?

2. Is the Group Owner IP means the IP address of Phone-A

Answer 1

To get IP address, you have to use 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; }
         */
    }