（Android）如何查找连接到我的Wi-Fi的其他设备的IP地址？

Question

我找到了解决方案。但这需要很长时间。给定代码尝试ping子网下的每个IP地址。例如，如果超时给出100ms，那么完成整个过程需要25.5秒。最佳方式是什么？

public class MainActivity extends Activity {

Button button;
EditText textview;

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;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    button = (Button)findViewById(R.id.button1);
    textview = (EditText)findViewById(R.id.ipList);

}

public void NetworkDetect(View v)
{


    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);

    String connections = "";
    InetAddress host;

    StrictMode.ThreadPolicy policy = new StrictMode. ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);

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

        System.out.println("Start: ");
        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";
                textview.append(address.toString()+"\n");
            }
            else if(!address.getHostAddress().equals(address.getHostName()))
            {
                System.out.println(address + " machine is known in a DNS lookup");
            }

        }
        System.out.println("End");

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

}
public String intToIp(int addr) {
    return  ((addr & 0xFF) + "." +
            ((addr >>>= 8) & 0xFF) + "." +
            ((addr >>>= 8) & 0xFF) + "." +
            ((addr >>>= 8) & 0xFF));
}

}