public static boolean isUp(String IP, int port) {
    Socket s = null;
    try {
        s = new Socket();
        s.setSoTimeout(10);
        s.connect(new InetSocketAddress(IP, port), 10);
        return true;
    } catch(IOException ex) {
        return false;
    } finally {
        if(s.isConnected()) {
            try {
                s.close();
                return true;
            } catch(IOException ex) {
                return false;
            }
        } else {
            return false;
        }
    }
}

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

    TextView textView = findViewById(R.id.textView)

    textView.setText("10.0.0.138:80 is " + (isUp("10.0.0.138", 80) ? "up" : "down") + "!")
}

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