I'm experimenting with socket communication between android and windows.
Everything works fine till i use the 10.0.2.2 address which is the loopback to the computer on which the emulator is running. But if i give any other address to the Socket constructor the connection is timing out.
My goal is to communicate between my phone and my computer through the internet.
I also tried it on my phone, so i don't think that it's a firewall problem.
Here is my code:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
clientSocket = new Socket("10.0.2.2", 48555);
Log.d("Offdroid", "socket connected");
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println(e.toString());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println(e.toString());
}
}
public void connectServer(View button) {
try {
String message = "shutdown";
byte[] messageBytes = message.getBytes("US-ASCII");
int messageByteCount = messageBytes.length;
byte[] messageSizeBytes = new byte[2];
messageSizeBytes = intToByteArray(messageByteCount);
byte[] sendBytes = concatenateArrays(messageSizeBytes, messageBytes);
Log.d("Offdroid", Integer.toString(messageSizeBytes.length));
clientSocket.setReceiveBufferSize(16);
clientSocket.setSendBufferSize(512);
OutputStream outStream = clientSocket.getOutputStream();
//InputStream inStream = clientSocket.getInputStream();
outStream.write(sendBytes, 0, sendBytes.length);
} catch(Exception EX) {
Log.e("Offdroid", EX.getMessage());
}
}
I'm also looking for a java built in function instead of the concatenateArrays function which simply put two byte array together.
Edit:
Sorry, maybe i not provided enough information. I have already tried my external ip used for the internet connection and my LAN ip. Port on router is forwarded to my computer. So if i write "192.168.1.101" or the ip given by the internet service provider in place of "10.0.2.2", than i cannot connect.
Edit:
Ok, i figured out it was my firewall.
Emulator takes uses the same network as that of your computer, so it will be able to route it to the computer. But for your phone to connect with your computer, you have to give a different IP, which is basically the IP of the computer.
I am guessing you are using some shared Network, and getting this (10.0.2.2) IP. Your computer should be directly connected to Internet in order for this to work from phone.
Ok, i figured out it was my firewall.
When you use a real Android phone as Internet Remote device, don't you have to set up your WiFi router, connected to your PC (or Android), for Port Forwarding? Then you give your Android Client the PC Server's External IP Address and the Server Port Number. Only then, provided the Port Forwarding works on the router, your remote Android Client (on SIM) can communicate with your PC Server connected to your router.
Related
I'm trying to send UDP packets from an emulated device (Nexus S 4.0", 480 x 800: hdpi) to my host PC for development and testing. The sending side seems correct and doesn't encounter any errors, but Wireshark indicates they are not arriving at the host PC. I've researched this problem and all the fixes that worked for others are not working for me:
I added "uses-permission android:name="android.permission.INTERNET" to the maifest XML file. (I also have ACCESS_NETWORK_STATE but I don't think that's necessary for this.)
I am sending the packets to the host loopback address 10.0.2.2. The port is 5006, so it's not one that I should need special privileges for.
I am calling DatagramSocket.send() in a dedicated thread, not in the main thread. (I think this would throw NetworkOnMainThreadException anyway, and I'm not getting any exceptions.)
I have Telnet-ed into "localhost 5444" and issued the "redir add udp:5006:5006" command to setup UDP port forwarding on the emulator's virtual router. The command returns "OK" without error, and "redir list" returns "udp:5006 => 5006".
I've also setup UDP port forwarding (port 5006) on my host PC's router (between PC and open internet). But I don't think that should be necessary, this router is not between the emulator and the host PC.
I have disabled Windows firewall and anti-virus on the host PC.
Here is the relevant code in my MainActivity.java. The start() and stop() methods are called from button clicks (omitted because they are not part of the problem):
private static String TAG = "MainActivity";
private volatile boolean running = false;
private String ip = "10.0.2.2";
private int port = 5006;
public void start(View view) {
new Thread() {
public void run() {
byte[] bytes = "Hi from UDPSender!".getBytes();
try {
InetAddress inetAddr = InetAddress.getByName(ip);
running = true;
while (running == true) {
DatagramPacket packet = new DatagramPacket(bytes, bytes.length, inetAddr, port);
DatagramSocket socket = new DatagramSocket();
socket.setBroadcast(false);
socket.send(packet);
socket.close();
Log.d(TAG, "Send packet to "+packet.getAddress().getHostAddress()+":"+packet.getPort());
Thread.sleep(1000);
}
} catch (Exception e) {
Log.e(TAG, e.getMessage(), e);
}
}
}.start();
}
public void stop(View view) {
running = false;
}
I'm developing a mobile application in android.
Here I want to detect the IP address of the computer,system,etc after the usb tethering of the any android phone
I cannot find the solution.
If I put the following code then it takes the only the IP address of phone ,I need IP address of system
The following are code
ArrayList<InetAddress> arrayList=new ArrayList<InetAddress>();
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();
arrayList.add(inetAddress);
inetAddress=null;
}
}
} catch (SocketException ex) {
Log.e("SALMAN", ex.toString());
}
return arrayList;
Please help me to get the system's IP address,If we cannot able to get means so please mention me. Because I'm new to android.
I'm using android 1.6 .
There is server side application in the windows xp system. That application is a windows service which is developed by C# .net.
That windows service listen to some port such like 234,etc.If some data comes to port then it will process the data and send response through that port.
In android the android application is send the data to the windows service via socket.
The android phone is USB tethered to the system in which windows service is running.Then system assume android phone is modem and additional IP address is generated for the system.This ip address is dynamically generated when the android phone is tethered.
For data transfer form mobile to system via socket .I will need to give the ip address of the system (after tethered) in my android coding.
If there is any method in android coding to get this IP address.
All are please give your ideas on regarding this.
Its not possible to find IP address created in PC from android after tethering. There is no API or other way to find it.
If you use InetAddress , it will return 192.168.42.129 - which is a DHCP address created by USB Tethering. It wont help you to communicate.
The other way is to scan the list of IP. USB Tethering will create ip ranging for 192.168.42.1 to 192.168.42.255 . You can write a simple scanner to find which one is active. But it will take some time.
Thanks to 'Swim N Swim' above. I found a code at
Retrieve IP and MAC addresses from /proc/net/arp (Android)
and modified a bit to get first IP having valid mac address. Works great when developing as a single user on your PC with tethered. You may follow above link for further selective IPs based on company name etc.
public static String getUSBThetheredIP() {
BufferedReader bufferedReader = null;
String ips="";
try {
bufferedReader = new BufferedReader(new FileReader("/proc/net/arp"));
String line;
while ((line = bufferedReader.readLine()) != null) {
String[] splitted = line.split(" +");
if (splitted != null && splitted.length >= 4) {
String ip = splitted[0];
String mac = splitted[3];
if (mac.matches("..:..:..:..:..:..")) {
if (mac.matches("00:00:00:00:00:00")) {
//Log.d("DEBUG", "Wrong:" + mac + ":" + ip);
} else {
//Log.d("DEBUG", "Correct:" + mac + ":" + ip);
ips = ip;
break;
}
}
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally{
try {
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return ips;
}
Note that each time you tether after untether, you must start your apache or other processes on PC to take new IP effective. THis is what I experienced.
I'am use TCP for connect my android phone with Windows 7 PC. When I'am send message phone-PC in LAN this system is work, as i`am use this system in Internet she is down because android app send me "time out". Why?
// The host name can either be a machine name, such as "java.sun.com", or a
// textual representation of its IP address
String host = "10.26.144.118";
int port = 20;
try {
Socket socket = new Socket(InetAddress.getByName(host), port);
BufferedReader reader = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
PrintWriter writer = new PrintWriter(socket.getOutputStream(), true);
// true for auto flush
writer.println("Hello World");
myView.setText("Send hello world");
} catch (Exception e) {
System.out.println("Error" + e);
myView.setText("Error" + e);
}
You are probably looking for port-forwarding
Your problem is that you mixed up the LAN (local area network) with the WAN (wide area network) aka the internet. Your personal LAN is protected from outside.
You need a static public IP or a DDNS (Dynamic DNS) solution e.g. dyndns. Than you have to forward the traffic from your public IP to you internal Server IP. See also thax's answer.
Than can your smartphone connect to your static public ip or to your DDNS address. Than should your app also work with the mobile network.
I have spent some time researching Android's ability to communicate with bluetooth devices that are designed to communicate over a Bluetooth COM port on a PC. I haven't been able to find a definitive answer, so I thought I'd ask here. I want to make sure that this is possible with Android.
I am new to Bluetooth communications, but the research I've done so far lead me to RFCOMM which somewhat sounded like what I wanted. Unfortunately, I'm still unable to confirm that this is in fact possible.
Any help/resources on this would be greatly appreciated.
Yes, Android can connect to Bluetooth COM ports on PC's. I am currently developing such an application. Here is a code example (Ite requires the bluetooth permissions te be set in the Manifest.xml file):
<uses-permission android:name="android.permission.BLUETOOTH" />
Java:
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
if (adapter == null) {
// Device does not support Bluetooth
finish(); //exit
}
if (!adapter.isEnabled()) {
//make sure the device's bluetooth is enabled
Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBluetooth, REQUEST_ENABLE_BT);
}
final UUID SERIAL_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); //UUID for serial connection
mac = "00:15:83:3D:0A:57"; //my laptop's mac adress
device = adapter.getRemoteDevice(mac); //get remote device by mac, we assume these two devices are already paired
// Get a BluetoothSocket to connect with the given BluetoothDevice
BluetoothSocket socket = null;
OutputStream out = null;
try {
socket = device.createRfcommSocketToServiceRecord(SERIAL_UUID);
} catch (IOException e) {}
try {
socket.connect();
out = socket.getOutputStream();
//now you can use out to send output via out.write
} catch (IOException e) {}
I'm trying to get my android app to connect to a socket on a server across the internet. I notice that when I have my Wi-fi turned on in the phone, the App can successfully connect to the port, but if I turn off the wi-fi, I get a time out on the connection. I can access and browse the internet on the phone seamlessly when wi-fi is off but connecting to that server always fails.
I've verified that the server is listening on that port and I can always connect from any other computer across the internet and on the phone if wi-fi is enabled.
I'm wondering what could be different between using the wireless connection and the cell connection to reach that location. The IP I'm using to connect to the address is a public address.
Button SendButton = (Button) findViewById(R.id.SendButton);
SendButton.setOnClickListener(new Button.OnClickListener() {
#Override
public void onClick(View v) {
Socket kkSocket = null;
PrintWriter out = null;
try {
kkSocket = new Socket("X.X.X.X", 4444);
out = new PrintWriter(kkSocket.getOutputStream(), true);
} catch (UnknownHostException e) {
System.err.println("Don't know about host: X.X.X.X");
} catch (IOException e) {
System.err.println("Couldn't get I/O for the connection to: X.X.X.X");
}