I am developing an Android multiplayer game using Wi-Fi direct.
Using Wi-Fi direct, I am able to establish connection between peer devices. Also the code is able to send the data from client device to server device. (According to Android documentation, the Wi-Fi direct uses client-server model)
Problem:
I am not able to share the data from server device to client device using Wi-Fi direct.
I have following questions:
Is there any other way to transfer data (bi-directional) between two
Android devices which are connected through Wi-Fi Direct?
During my online research I understood that to send data from server
device to client device, server needs to know the client’s IP
address. How to use this client’s IP address to send data from
server device to client device? (I am able to fetch the client’s IP
address)
I'd appreciate any suggestions on these queries. Thank you in advance.
Code:
Server Side
public class DataTransferAsyncTask extends AsyncTask<Void,Void,String>{
ServerSocket serverSocket;
Socket client;
InputStream inputstream;
Context context = mActivity.getApplicationContext();
String s;
InetAddress client_add;
#Override
protected String doInBackground(Void... voids) {
try{
serverSocket = new ServerSocket(9999);
Log.e("hello", "Server: Socket opened");
client = serverSocket.accept();
Log.e("hello", "Server: connection done");
inputstream = client.getInputStream();
// OutputStream outputStream = serverSocket.getO
//getting data from client
byte[] address = new byte[12];
if(client.isConnected())
inputstream.read(address);
s = new String(address);
String only_add = new String();
only_add = s.substring(0,12);
client_add = InetAddress.getByName(only_add);
Log.e("hello", "Server: clients ip 1 " + only_add);
Log.e("hello", "Server: converted address 1 " + client_add + " \n is connected"+
client.isConnected());
//send data to client
OutputStream stream = client.getOutputStream();
stream.write(s.getBytes());
Log.e("hello","context value "+context);
// cancel(true);
}catch (IOException e){
}
return null;
}
}
Client Side:
#override
protected void onHandleIntent(Intent intent) {
Log.e("hello","client socket");
Toast.makeText(this,"client socket",Toast.LENGTH_LONG).show();
Context context = getApplicationContext();
if(intent.getAction().equals(action_send_data)){
String host = intent.getStringExtra(group_owner_address);
Socket socket = new Socket();
int port = intent.getIntExtra(group_owner_port,9999);
//binding connection
try{
String x="hello";
Log.e("hello","opening client socket");
byte[] address = getLocalAddress();
String ipAdd = getDottedDecimalIP(address);
socket.bind(null);
socket.connect(new InetSocketAddress(host,port),socket_timeout);
Log.e("hello","device socket address "+ socket.getInetAddress() );
Log.e("hello","client socket is connected"+socket.isConnected());
Log.e("hello","device address :"+ipAdd + " byte "+ address);
//sending data to server
OutputStream stream = socket.getOutputStream();
stream.write(ipAdd.getBytes());
//getting data from the server(supposed to)
InputStream inputstream = socket.getInputStream();
byte[] address_to_sto_fr_ser = new byte[15] ;
inputstream.read(address_to_sto_fr_ser);
String s = new String(address_to_sto_fr_ser);
Log.e("msg from server","msg from server "+s);
// stream.close();
// is.close();
}catch (IOException e){
}
}
}
The communication between client and WiFi Direct Group Owner is based on Socket server running on the Group Owner and clients connected to that server.
Once WiFi Direct group is formed(you can know that by checking "onConnectionInfoAvailable(WifiP2pInfo wifiP2pInfo)"), check if the current device is the Group Owner and if so, start the sockets server (similar to your code):
mServerSocket = new ServerSocket(mPort);
Log.e(getClass().getSimpleName(), "Running on port: " + mServerSocket.getLocalPort());
Then next, add this line to accept connections and store a reference of the client socket:
Socket mSocket = mServerSocket.accept();
Now, you have a reference of the client socket, you can use it to send data / messages to it. Next, the other device (client) should initiate a connection to the socket server:
mSocket = new Socket();
mSocket.bind(null);
mSocket.connect(new InetSocketAddress(mAddress, mPort), 500);
To send message from server to client:
DataOutputStream mDataOutputStream = new DataOutputStream(mSocket.getOutputStream());
Send simple message:
mDataOutputStream.writeUTF(message);
mDataOutputStream.flush();
Hope this helps.
Related
Can anyone suggest a good example for get an idea about creating TCP server and client with android WiFi direct to transfer data. (Actually transfering of strings not files)
Actually I did one, but I cannot get the IP of server from client side.
If server and client are connected to the same wifi network, then please try use the 192.168.1.40 IP in the client to send data to server.
For example in client:
Socket socket = new Socket("192.168.1.40", port);
Hope it helps.
package com.example.androidclient;
MyClientTask(String addr, int port){
dstAddress = addr;
dstPort = port;
}
try {
socket = new Socket(dstAddress, dstPort);
ByteArrayOutputStream byteArrayOutputStream =
new ByteArrayOutputStream(1024);
byte[] buffer = new byte[1024];
int bytesRead;
InputStream inputStream = socket.getInputStream();
catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "UnknownHostException: " + e.toString();
}
I'm trying to send a simple string from an android device to a pc.
I managed to send the string via wifi (because is on a LAN network), but the code doesn't work over 3g.
The code i'm using is this:
class send extends AsyncTask
{
#Override
protected Object doInBackground(Object... params) {
try {
InetAddress serverAddr = InetAddress.getByName("IP here")
Socket socket = new Socket(serverAddr, 8564);
String message = "sample_message";
try {
PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);
out.println(message);
} catch(Exception e) {}
finally {
socket.close();
}
} catch (Exception e) {}
return null;
}
}
Where is your PC connected? Is it a LAN behind NAT? Are you using the LAN IP address as serverAddr? What is "IP here"?
If you are using a local network IP address behind the NAT you'll never be able to connect.
If you have a router/wifi AP, enable port forwarding to you PC and use the public IP address provided by the ISP as serverAddr.
Have you tried creating a DataOutputStream like
DataOutputStream dos=new DataOutputStream(socket.getOutputStream());
dos.writeBytes(message + '\n');
Instead of :
PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);
out.println(message);
I am trying to send a file over bluetooth in an android device. I have done discovery, connection and have made a bluetooth socket. Problem is when i am writing the byte array in the output stream of the bluetooth socket, the recieving side does not receive anything although it accept that something is being sent.
Here's what Iam doing (bad is the bluetooth adaptor)
Please advise.
try
{
BluetoothDevice dev = bad.getRemoteDevice(a);
bad.cancelDiscovery();
dev.createRfcommSocketToServiceRecord(new UUID(1111, 2222));
Method m = dev.getClass().getMethod("createRfcommSocket", new Class[] {int.class});
bs = (BluetoothSocket) m.invoke(dev, Integer.valueOf(1));
bs.connect();
tmpOut = bs.getOutputStream();
}catch(Exception e)
{
}
File f = new File(filename);
byte b[] = new byte[(int) f.length()];
try
{
FileInputStream fileInputStream = new FileInputStream(f);
fileInputStream.read(b);
}catch(IOException e)
{
Log.d(TAG, "Error converting file");
Log.d(TAG, e.getMessage());
}
try {
tmpOut.write(b);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
I am using the below code snipped to connect to the serial service in a remote Bluetooth device and it is working fine for me. Just make sure that the other device (can be mobile or PC) has a server socket for serial communication over Bluetooth (see the server side code below)
Client Side:
UUID serialUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
BluetoothDevice btDevice = btAdapter.getRemoteDevice(BTAddress); // Get the BTAddress after scan
BluetoothSocket btSocket = btDevice.createRfcommSocketToServiceRecord(SERIAL_UUID);
btSocket.connect();
InputStream iStream = btSocket.getInputStream();
OutputStream oStream = btSocket.getOutputStream();
Server Side:
UUID serialUUID = new UUID("1101", true);
String serviceURL = "btspp://localhost:" + serialUUID
+ ";name=Android BT Server;authorize=false;authenticate=false";
StreamConnectionNotifier connectionNotifier = (StreamConnectionNotifier) Connector
.open(serviceURL);
// Blocking method will wait for client to connect
StreamConnection connection = connectionNotifier.acceptAndOpen();
RemoteDevice remoteDevice = RemoteDevice.getRemoteDevice(connection);
InputStream btInput = connection.openInputStream();
OutputStream btOutput = connection.openOutputStream();
Why not use the standard api call instead of calling through reflection, eg:
BluetoothSocket socket = destination
.createRfcommSocketToServiceRecord(new UUID(...)) ;
Also your catch block is empty. Are you sure the socket was connected without any exception? Connect will throw IOException if the connection failed for some reason. See this link
It might be because dev and bs go out of scope before tmpout is used because they are declared within your try/catch block.
I need to receive data packets send from a GSM modem through GPRS with my android mobile...
Can any one help me how to send and receive..
What protocol has to be used?
Create a Thread in server starts and do the following
ServerSocket serverSocket = new ServerSocket(8000); //8000 - port number
Socket client = serverSocket.accept(); // thread will wait here till a client connects
BufferedReader inFromClient = new BufferedReader(
new InputStreamReader(client.getInputStream()));
DataOutputStream outToClient = new DataOutputStream(
client.getOutputStream());
while ((inputLine = inFromClient.readLine()) != null) {
System.out.println("Server: " + inputLine);
if(inputLine.equals("END"))
{
outToClient.writeBytes("END\n");
}
else
{
outToClient.writeBytes("Received\n");
}
}
inFromClient.close();
outToClient.close();
Its a TCP connection you need to handle
Im a newbie in this so please escuse me if i ask dumb questions.
Im trying to make a UDP connection between Eclipse's PC Emulator & a android phone
(or between two android phone devices).
I have a router and the phone connects to the internet thru router's wifi network. The PC is on same network also (direct cable router-PC connection). Im trying to send some text data from Server thread to Client thread but nothing is received/sent. :(
The Server java class (RE-EDITED, Server receives msg. from Client):
public class server implements Runnable
{
// the Server's Port
public static final int SERVERPORT = 6000;
// running Server thread.
public void run()
{
Log.d("redwing","server thread started.");
DatagramSocket serverSocket = null;
try
{
// Open Server Port
serverSocket = new DatagramSocket(server.SERVERPORT);
byte[] receiveData = new byte[32];
byte[] sendData = new byte[32];
// loop until "server_finished" becomes False.
while(createserver.server_finished)
{
if(renderer.gGL!=null) // ignore me, just a null pointer checker
{
// waiting for the incoming client's message packet
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
serverSocket.receive(receivePacket);
renderer.recv = new String(receivePacket.getData());
Log.d("server","packet received from client, ETA " + timing.getNow() + " " + renderer.recv); // timing getNow - just returns current system minute & second.
// server is replying to the client back with a message.
InetAddress IPAddress = receivePacket.getAddress();
int port = receivePacket.getPort();
sendData = new String("server msg").getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
serverSocket.send(sendPacket);
renderer.sent = new String(sendData, 0, sendData.length);
Log.d("server","packet sent to client, ETA " + timing.getNow() + " " + renderer.sent); // timing getNow - just returns current system minute & second.
}
}
// close the socket
if(serverSocket!=null) serverSocket.close();
serverSocket = null;
}
catch (Exception e)
{
Log.e("server", "Error", e);
if(serverSocket!=null) serverSocket.close();
serverSocket = null;
}
finally
{
if(serverSocket!=null) serverSocket.close();
serverSocket = null;
}
Log.d("redwing","server thread terminated.");
}
}
and the Client java class (RE-EDITED, Client does not receive msg from Server) :
public class client implements Runnable
{
public static final int CLIENTPORT = 5000;
// running Client thread.
public void run()
{
Log.d("redwing","client thread started.");
DatagramSocket clientSocket = null;
try
{
// getting local address
clientSocket = new DatagramSocket(server.SERVERPORT);
InetAddress IPAddress = InetAddress.getByName("192.168.0.100");
// displaying IP & hostname.
Log.d("client", "IP: " + IPAddress.getHostAddress() + " Name: " + IPAddress.getHostName());
byte[] sendData = new byte[32];
byte[] receiveData = new byte[32];
// Loop until client_finished becomes False.
while(createclient.client_finished)
{
if(renderer.gGL!=null) // ignore me, just a null pointer checker
{
// sending a message to the server
sendData = timing.getNow().getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, client.CLIENTPORT);
clientSocket.send(sendPacket);
renderer.sent = new String(sendData,0,sendData.length);;
Log.d("client","packet sent to server, ETA " + timing.getNow());
// waiting for the server packet message.
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
clientSocket.receive(receivePacket);
renderer.recv = new String(receivePacket.getData());
Log.d("client","packet received from server, ETA " + timing.getNow());
}
}
// close the socket
if(clientSocket!=null) clientSocket.close();
clientSocket = null;
}
catch (Exception e)
{
Log.e("client", "Error", e);
if(clientSocket!=null) clientSocket.close();
clientSocket = null;
}
finally
{
if(clientSocket!=null) clientSocket.close();
clientSocket = null;
}
Log.d("redwing","client thread terminated.");
}
}
the Permisions are enabled in the manifest:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.INTERNET"/>
<user-permission android:name="android.permission.NETWORK" />
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
I'm running the Server on the android PC Emulator, and the Client on my android Phone.
Both Client & Server threads run just fine but ... the problem is that i dont get any data exchanged between them. The client doesn't receive anyting and the server doesnt receive anything. The packets are sent but nothing received .
What im doing wrong ?
Please help me.
Thank you in advance.
After running your emulator, type it in command prompt - "telnet localhost ", then type "redir add udp:5000:6000". Connect client with port number 5000 and open udp server with port number 6000. Then you can receive client message from udp server.
Take a look for details
clientSocket = new DatagramSocket();
InetAddress IPAddress = InetAddress.getByName("<pc ip>"); // instead of "localhost"
public static final String SERVERIP = "127.0.0.1"; // 'Within' the emulator!
public static final int SERVERPORT = 6000;
/* Retrieve the ServerName */
InetAddress serverAddr = InetAddress.getByName(SERVERIP);
DatagramSocket socket = new DatagramSocket(SERVERPORT, serverAddr);