How i can get the ip address for connected device with hotspot programmatically

Question

I have an Android POS device and it is connected to my Android phone through a mobile hotspot, I need to get the IP Address for the POS programmatically without letting the user enter it, I can get the Ip address from Android mobile hotspot settings like the below image, but I need to get it from inside my application.

I tried to access BufferedReader(new FileReader("/proc/net/arp")) but gave me denied permission and it's not accessible from Android 10 and more.

what are the alternatives to get the same data as the attached image?

score 0 · Answer 1 · answered Apr 13 '23 at 10:24

I would leave a comment but since that doesn't work:

I would try the idea that the devices in your hotspot are in the same network like your device. So, I would suggest to go over the host ip. So first get the host ip:

public String   s_dns1 ;
public String   s_dns2;     
public String   s_gateway;  
public String   s_ipAddress;    
public String   s_leaseDuration;    
public String   s_netmask;  
public String   s_serverAddress;
TextView info;
DhcpInfo d;
WifiManager wifii;

wifii = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    d = wifii.getDhcpInfo();

    s_dns1 = "DNS 1: " + String.valueOf(d.dns1);
    s_dns2 = "DNS 2: " + String.valueOf(d.dns2);
    s_gateway = "Default Gateway: " + String.valueOf(d.gateway);
    s_ipAddress = "IP Address: " + String.valueOf(d.ipAddress);
    s_leaseDuration = "Lease Time: " + String.valueOf(d.leaseDuration);
    s_netmask = "Subnet Mask: " + String.valueOf(d.netmask);
    s_serverAddress = "Server IP: " + String.valueOf(d.serverAddress);

And then get the connected ips:

String connections = "";
    InetAddress host;
    try
    {
        host = InetAddress.getByName(intToIp(d.dns1));
        byte[] ip = host.getAddress();

        for(int i = 1; i <= 254; i++)
        {
            ip[3] = (byte) i;
            InetAddress address = InetAddress.getByAddress(ip);
            if(address.isReachable(100))
            {
                System.out.println(address + " machine is turned on and can be pinged");
                connections+= address+"\n";
            }
            else if(!address.getHostAddress().equals(address.getHostName()))
            {
                System.out.println(address + " machine is known in a DNS lookup");
            }

        }
    }
    catch(UnknownHostException e1)
    {
        e1.printStackTrace();
    }
    catch(IOException e)
    {
        e.printStackTrace();
    }
   System.out.println(connections);

Now convert it to String:

public String intToIp(int i) {
    return (i & 0xFF) + "." +
            ((i >> 8 ) & 0xFF) + "." +
            ((i >> 16) & 0xFF) + "." +
            ((i >> 24) & 0xFF);
}

This solution is provided by: https://stackoverflow.com/a/21091575/7173050

How i can get the ip address for connected device with hotspot programmatically

1 Answers1