Retrieving Device IP in Kotlin Android

Retrieving the local IPv4 address of a device in Kotlin on Android can be useful in a variety of scenarios, such as network programming or online gaming. In this guide, we will walk you through the process of retrieving the local IPv4 address using the java.net.InetAddress class.

Here is the code for retrieving the local IPv4 address:

import java.net.InetAddress
import java.net.NetworkInterface

fun getLocalIPAddress(): String? {
    try {
        val en = NetworkInterface.getNetworkInterfaces()
        while (en.hasMoreElements()) {
            val networkInterface = en.nextElement()
            val enu = networkInterface.inetAddresses
            while (enu.hasMoreElements()) {
                val inetAddress = enu.nextElement()
                if (!inetAddress.isLoopbackAddress && inetAddress is Inet4Address) {
                    return inetAddress.getHostAddress()
                }
            }
        }
    } catch (ex: Exception) {
        ex.printStackTrace()
    }

    return null
}

In this code, the getLocalIPAddress function uses the NetworkInterface class to retrieve a list of network interfaces and their associated IP addresses. The function loops through the interfaces and IP addresses, checking if each address is a loopback address or an IPv4 address. If an IPv4 address is found that is not a loopback address, it is returned as the local IP address.

Note that there may be multiple network interfaces on a device, and each interface may have multiple IP addresses. This code will return the first non-loopback IPv4 address that it finds.

To use the local IP address in your code, you can simply call the getLocalIPAddress function and store the result in a variable. For example:

val localIPAddress = getLocalIPAddress()

And that's it! You now have the local IPv4 address of the device in a Kotlin program on Android. You can use this address for various purposes, such as connecting to a server or sending data over a network.