在AndroidManifest.xml中声明ACCESS_WIFI_STATE权限:

<uses-permission
    android:name="android.permission.ACCESS_WIFI_STATE"/>

可以通过WifiManager获取IP地址:

Context context = requireContext().getApplicationContext();
WifiManager wm = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
String ip = Formatter.formatIpAddress(wm.getConnectionInfo().getIpAddress());

这是这个答案的返工，去掉了不相关的信息，添加了有用的评论，更清楚地命名变量，并改进了逻辑。

不要忘记包含以下权限:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

InternetHelper.java:

public class InternetHelper {

    /**
     * Get IP address from first non-localhost interface
     *
     * @param useIPv4 true=return ipv4, false=return ipv6
     * @return address or empty string
     */
    public static String getIPAddress(boolean useIPv4) {
        try {
            List<NetworkInterface> interfaces =
                    Collections.list(NetworkInterface.getNetworkInterfaces());

            for (NetworkInterface interface_ : interfaces) {

                for (InetAddress inetAddress :
                        Collections.list(interface_.getInetAddresses())) {

                    /* a loopback address would be something like 127.0.0.1 (the device
                       itself). we want to return the first non-loopback address. */
                    if (!inetAddress.isLoopbackAddress()) {
                        String ipAddr = inetAddress.getHostAddress();
                        boolean isIPv4 = ipAddr.indexOf(':') < 0;

                        if (isIPv4 && !useIPv4) {
                            continue;
                        }
                        if (useIPv4 && !isIPv4) {
                            int delim = ipAddr.indexOf('%'); // drop ip6 zone suffix
                            ipAddr = delim < 0 ? ipAddr.toUpperCase() :
                                    ipAddr.substring(0, delim).toUpperCase();
                        }
                        return ipAddr;
                    }
                }

            }
        } catch (Exception ignored) { } // if we can't connect, just return empty string
        return "";
    }

    /**
     * Get IPv4 address from first non-localhost interface
     *
     * @return address or empty string
     */
    public static String getIPAddress() {
        return getIPAddress(true);
    }

}

虽然有一个正确的答案，我在这里分享我的答案，希望这样会更方便。

WifiManager wifiMan = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInf = wifiMan.getConnectionInfo();
int ipAddress = wifiInf.getIpAddress();
String ip = String.format("%d.%d.%d.%d", (ipAddress & 0xff),(ipAddress >> 8 & 0xff),(ipAddress >> 16 & 0xff),(ipAddress >> 24 & 0xff));

你可以这样做

String stringUrl = "https://ipinfo.io/ip";
//String stringUrl = "http://whatismyip.akamai.com/";
// Instantiate the RequestQueue.
RequestQueue queue = Volley.newRequestQueue(MainActivity.instance);
//String url ="http://www.google.com";

// Request a string response from the provided URL.
StringRequest stringRequest = new StringRequest(Request.Method.GET, stringUrl,
        new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                // Display the first 500 characters of the response string.
                Log.e(MGLogTag, "GET IP : " + response);

            }
        }, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        IP = "That didn't work!";
    }
});

// Add the request to the RequestQueue.
queue.add(stringRequest);

WifiManager wm = (WifiManager) getSystemService(WIFI_SERVICE);
String ipAddress = BigInteger.valueOf(wm.getDhcpInfo().netmask).toString();

public static 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() && inetAddress instanceof Inet4Address) {
                    return inetAddress.getHostAddress();
                }
            }
        }
    } catch (SocketException ex) {
        ex.printStackTrace();
    }
    return null;
}

我已经添加了inetAddress instanceof Inet4Address来检查它是否是ipv4地址。