how to get the IP of the wifi hotspot in Android?

Question

As the title says... I'm trying to be able to get the IP of the wifi iface when it is configured as hotspot. Ideally, I would like to find something that works for all the phones.

Of course, the WifiManager is useless when it comes to get info from the AP.

Luckily, I've been able to get the IPs of all the interfaces by doing this:

public String getLocalIpAddress() {
    try {
        for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
            NetworkInterface intf = en.nextElement();
            for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
                InetAddress inetAddress = enumIpAddr.nextElement();
                if (!inetAddress.isLoopbackAddress()) {
                    Log.d("IPs", inetAddress.getHostAddress() );
                }
            }
        }
    } catch (SocketException ex) {
        Log.e(LOG_TAG, ex.toString());
    }
    return null;
}

This chunk of code will print all the IP of all the interfaces (Wifi hotspot included). The main problem is that I don't find a way to identify the WiFi interface. This is an issue since some phones have multiple interfaces (WiMax, etc). This is what I've tried so far:

• Filtering by the wifi iface display name: it's not a good approach because the display name changes from one device to another (wlan0, eth0, wl0.1, etc).
• Filtering by its mac address: almost work, but on some devices the hotspot iface does not have a MAC address ( iface.getHardwareAddress() returns null)...so not a valid solution.

Any suggestions?

Answer 1

Here's what I did to get the wifi hotspot ip:

public String getWifiApIpAddress() {
    try {
        for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en
                .hasMoreElements();) {
            NetworkInterface intf = en.nextElement();
            if (intf.getName().contains("wlan")) {
                for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr
                        .hasMoreElements();) {
                    InetAddress inetAddress = enumIpAddr.nextElement();
                    if (!inetAddress.isLoopbackAddress()
                            && (inetAddress.getAddress().length == 4)) {
                        Log.d(TAG, inetAddress.getHostAddress());
                        return inetAddress.getHostAddress();
                    }
                }
            }
        }
    } catch (SocketException ex) {
        Log.e(TAG, ex.toString());
    }
    return null;
}

This will give you the IP address of any wifi device, which means it's not just for the hotspot. If you're connected to another wifi network (meaning you're not in hotspot mode), it'll return an IP.

You should check if you are in AP mode first or not. You can use this class for that: http://www.whitebyte.info/android/android-wifi-hotspot-manager-class

Answer 2

You can use this.

((WifiManager) mContext.getSystemService(Context.WIFI_SERVICE)).getDhcpInfo().serverAddress

Full Code

private String getHotspotIPAddress() {

    int ipAddress = mContext.getSystemService(Context.WIFI_SERVICE)).getDhcpInfo().serverAddress;

    if (ByteOrder.nativeOrder().equals(ByteOrder.LITTLE_ENDIAN)) {
        ipAddress = Integer.reverseBytes(ipAddress);
    }

    byte[] ipByteArray = BigInteger.valueOf(ipAddress).toByteArray();

    String ipAddressString;
    try {
        ipAddressString = InetAddress.getByAddress(ipByteArray).getHostAddress();
    } catch (UnknownHostException ex) {
        ipAddressString = "";
    }

    return ipAddressString;

}