Android Debugging Inetaddress.Isreachable

Checking Host Reachability/Availability in Android

It's not pretty but this is how I did it:

boolean exists = false;

try {
    SocketAddress sockaddr = new InetSocketAddress(ip, port);
    // Create an unbound socket
    Socket sock = new Socket();

    // This method will block no more than timeoutMs.
    // If the timeout occurs, SocketTimeoutException is thrown.
    int timeoutMs = 2000;   // 2 seconds
    sock.connect(sockaddr, timeoutMs);
    exists = true;
} catch(IOException e) {
    // Handle exception
}

Latency time in android

For me, something like this does the trick:

Process process = Runtime.getRuntime().exec("ping -c 1 google.com");
process.waitFor();

You can regex through the answer by reading InputStream provided by process.

Kotlin: NetworkOnMainThreadException error when trying to run InetAddress.isReachable()

As the exception says you are trying to do a network call on main thread which is prohibited.

An easy way to fix this would be to make the function suspendable and switch to a background thread

private suspend fun hasConnection() {
    withContext(Dispatchers.IO) {
        var address: InetAddress = InetAddress.getByName("192.168.1.1")
        val timeout = 1500
        if (address.isReachable(timeout)){
            status.text = "Available"
        }else{
            status.text = "Disconnected"
        }
    }
}

When calling hasConnection() use lifecycleScope from Activity level to launch a coroutine which will call your hasConnection()

------------- Somewhere in your Activity -------------

lifecycleScope.launch {
    hasConnection()
}

isReachable() returns false in android

Well, i found that android keep MAC addreses of devices for about 10 min (On different devices - different time), and only way - use ADB shell command to clear that list, BUT! it works only on rooted devices.

But this code can help you (works not with all devices):

public void getListOfConnectedDevice() {
    final Thread thread = new Thread(new Runnable() {

        @Override
        public void run() {
            macAddresses.clear();
            BufferedReader br = null;
            boolean isFirstLine = true;
            try {

                br = new BufferedReader(new FileReader("/proc/net/arp"));
                String line;

                while ((line = br.readLine()) != null) {
                    if (isFirstLine) {
                        isFirstLine = false;
                        continue;
                    }

                    String[] splitted = line.split(" +");

                    if (splitted != null && splitted.length >= 4) {

                        String ipAddress = splitted[0];
                        String macAddress = splitted[3];

                        Node node = new Node(ipAddress, macAddress);
                        boolean isReachable = node.isReachable;
                        Log.d(TAG, "isReachable: " + isReachable);
                        if (isReachable) {
                            Log.d("Device Information", ipAddress + " : "
                                    + macAddress);
                            macAddresses.add(macAddress);
                        }
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    });
    thread.start();
}

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