I use socket.io-client-java library
I have android client and Java server
Server code:
public class Server {
public static void main(String[] args) throws IOException {
System.out.println("Welcome to Server side");
BufferedReader in = null;
PrintWriter out = null;
ServerSocket servers = null;
Socket fromclient = null;
// create server socket
try {
servers = new ServerSocket(4444);
} catch (IOException e) {
System.out.println("Couldn't listen to port 4444");
System.exit(-1);
}
try {
System.out.print("Waiting for a client...");
fromclient = servers.accept();
System.out.println("Client connected");
} catch (IOException e) {
System.out.println("Can't accept");
System.exit(-1);
}
in = new BufferedReader(new
InputStreamReader(fromclient.getInputStream()));
out = new PrintWriter(fromclient.getOutputStream(), true);
String input, output;
System.out.println("Wait for messages");
while ((input = in.readLine()) != null) {
if (input.equalsIgnoreCase("exit")) break;
out.println("S ::: " + input);
System.out.println(input);
}
out.close();
in.close();
fromclient.close();
servers.close();
}
}
And client:
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private Socket mSocket = null;
private Button button;
{
try {
mSocket = IO.socket(Constants.CHAT_SERVER_URL);
} catch (URISyntaxException e) {
throw new RuntimeException(e);
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.button);
button.setOnClickListener(this);
mSocket.connect();
}
#Override
public void onClick(View v) {
if (v.getId() == R.id.button){
mSocket.emit("new message", "Some message");
}
}
}
And if I tried connect to server I get this:
Welcome to Server side
Waiting for a client...Client connected
Wait for messages
GET /socket.io/?EIO=3&transport=polling HTTP/1.1
User-Agent: Dalvik/1.4.0 (Linux; U; Android 2.3.7; Android SDK built for x86 Build/GINGERBREAD)
Host: 10.0.2.2:4444
Connection: Keep-Alive
Accept-Encoding: gzip
But when I tried to send String message
mSocket.emit("new message", "Some message");
Nothing happens. I send the wrong or server is wrong?
To properly init socket.io client, you need to do something like this:
Socket _socket = IO.socket(SERVER_URI);
_socket.on(Socket.EVENT_CONNECT, _onConnectionListener)
.on(Socket.EVENT_DISCONNECT, _onDisconnectListener)
.on(Socket.EVENT_CONNECT_ERROR, _onConnectionErrorListener)
.on(Socket.EVENT_MESSAGE, _onMessageReceivedListener)
.on(CHAT_MESSAGE_PUBLISH, _onMessageReceivedListener);
Each of listeners is run when the event takes place, e.g.:
private Emitter.Listener _onMessageReceivedListener = new Emitter.Listener() {
#Override
public void call(Object... args) {
JSONArray jsonArray = (JSONArray) args[0];
if (jsonArray != null && jsonArray.length() > 0) {
Gson gson = new Gson();
List<MessageModel> historyList = gson.fromJson(jsonArray.toString(), listType);
loadReceivedMessage(historyList);
chatLoging(jsonArray.toString());
}
}
};
The call() method will be triggered when you a receive new message from the server.
Using this great tutorial by the Java Code Geeks, I am easily able to create a client activity that sends data via TCP to a server's port 4000 using the following code:
public class Client extends Activity {
private Socket socket;
private static final int SERVERPORT = 5000;
private static final String SERVER_IP = "10.0.2.2";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new Thread(new ClientThread()).start();
}
public void onClick(View view) {
try {
EditText et = (EditText) findViewById(R.id.EditText01);
String str = et.getText().toString();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
out.println(str);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
class ClientThread implements Runnable {
#Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
Then using their other snippet for the server activity I can catch messages using TCP on that port:
public class Server extends Activity {
private ServerSocket serverSocket;
Handler updateConversationHandler;
Thread serverThread = null;
private TextView text;
public static final int SERVERPORT = 6000;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
text = (TextView) findViewById(R.id.text2);
updateConversationHandler = new Handler();
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
}
#Override
protected void onStop() {
super.onStop();
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
class ServerThread implements Runnable {
public void run() {
Socket socket = null;
try {
serverSocket = new ServerSocket(SERVERPORT);
} catch (IOException e) {
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted()) {
try {
socket = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class CommunicationThread implements Runnable {
private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
try {
this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while (!Thread.currentThread().isInterrupted()) {
try {
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class updateUIThread implements Runnable {
private String msg;
public updateUIThread(String str) {
this.msg = str;
}
#Override
public void run() {
text.setText(text.getText().toString()+"Client Says: "+ msg + "\n");
}
}
}
My question is how can I make it so these 2 can communicate back and forth?
Android -> Server(4000) -> Android(4001)?
In other words how can I make my app help the device act as both the client (sending out data to another device on port 4000) and the server (listening for data on port 4001) at the same time?
On the Server side change the port to 5000 (same as Client) instead of 6000:
And you need to update the following class because you don't want to create a new socket, you should use the one already created (in the Client part).
NB: the socket given as an argument to CommunicationThread is the socket that you supposedly already created (Client part).
class ServerThread implements Runnable {
public void run() {
while (!Thread.currentThread().isInterrupted()) {
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
}
}
}
I've been working in a server/client application that needs to get the hour from a server working in my computer.
When I try to run this app in my phone it says that SOCKET NOT CONNECTED. I tried everything but it still not working.
The thread is working, but the socket is not connecting!
The permissions I used:
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
The MainActivity.java is:
package com.example.clientehora;
/* imports */
public class MainActivity extends Activity {
Socket socket = new Socket();
String SERVER_IP = "10.215.19.41";
int SERVERPORT = 2000;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread(new ClientThread()).start();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void ejecutar(View view) {
try {
System.out.println("Hola amigo, si me presionaste! =D" + socket.getInetAddress() + socket.getPort());
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String cadena = br.readLine();
System.out.println("LA CADENA ES: " +cadena);
EditText et = (EditText)findViewById(R.id.fecha);
et.setText(cadena);
br.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
class ClientThread implements Runnable {
#Override
public void run() {
try {
System.out.println("Se ha conectado sin problemas");
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
This works for me to connect to my Win7 PC via USB (mTimeout is 5000):
mSocket = new Socket();
mSocket.setSoTimeout(mTimeout);
mSocket.connect(new InetSocketAddress(SERVER_IP, SERVERPORT), mTimeout);
I get the IP to use using this command on the PC:
InetAddress.getLocalHost().getHostAddress()
I've built a TCP server and now I would like to turn it into a jar so I can use it in many different app. So basically later on I'd like to just include it in other projects. if it was just a list of functions I could figure it out but it's not I'm so I'm not sure. I thought about making it all just one function but it wouldn't run, when I called the function the app would just fail.
Also I hope other people can find this server code useful for their own projects
public class MainActivity extends Activity {
private ServerSocket serverSocket;
Handler updateConversationHandler;
Thread serverThread = null;
public String serverIP = "127.0.0.1";
private InetAddress serverAddr;
public static final int SERVERPORT = 4444;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
updateConversationHandler = new Handler();
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
}
#Override
protected void onStop() {
super.onStop();
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
class ServerThread implements Runnable {
public void run() {
Socket socket = null;
try {
serverSocket = new ServerSocket(SERVERPORT);
} catch (IOException e) {
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted()) {
try {
socket = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class CommunicationThread implements Runnable {
private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
try {
this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while (!Thread.currentThread().isInterrupted()) {
try {
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
I made a simple prototype of a client-server application on Android
I managed to connect two clients to the server and the server can receive their messages. The problem now is that I can't seem to broadcast/receive the messages to other clients.
I try to broadcast the received message through a for loop in the Server class:
private void broadcastMessage(String message) {
for (int i = 0, j = clients.size(); i <= j; i++) {
PrintWriter out = null;
Socket socket = clients.get(i);
try {
out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// WHERE YOU ISSUE THE COMMANDS
out.println(message);
Log.d("SERVER Loop", "Broadcasting messages...");
out.close();
}
Log.d("SERVER", "Message Brodcasted");
}
This I then try to receive through a listener in the Client class :
public class ClientThreadListener implements Runnable {
protected Socket serverSocket = null;
protected String mMsgFromServer;
public ClientThreadListener(Socket serverSocket) {
this.serverSocket = serverSocket;
}
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(
serverSocket.getInputStream()));
while ((mMsgFromServer = in.readLine()) != null) {
Log.d("MESSAGE FROM SERVER: ", mMsgFromServer);
handler.post(new Runnable() {
#Override
public void run() {
msgFromOtherClients.append('\n'
+ "Message From Server: " + mMsgFromServer);
}
});
}
} catch (Exception e) {
Log.e("ClientListener", "C: Error", e);
connected = false;
}
}
}
I don't get any errors or force closes though. Forgive me I know it is very messy but please bear with me and please focus on the issue at hand instead :D
Here is the full code for the Server class
public class Server extends Activity {
private TextView serverStatus;
// DEFAULT IP
public static String SERVERIP = "10.0.2.15";
// DESIGNATE A PORT
public static final int SERVERPORT = 8080;
private Handler handler = new Handler();
private ServerSocket serverSocket;
private String mMsgFromClient;
private MultiThreadedServer server;
private ArrayList<Socket> clients = new ArrayList<Socket>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.server);
serverStatus = (TextView) findViewById(R.id.server_status);
// SERVERIP = getLocalIpAddress();
server = new MultiThreadedServer(8080);
new Thread(server).start();
}
public class MultiThreadedServer implements Runnable {
protected int serverPort = 8080;
protected ServerSocket serverSocket = null;
protected boolean isStopped = false;
protected Thread runningThread = null;
public MultiThreadedServer(int port) {
this.serverPort = port;
}
public void run() {
synchronized (this) {
this.runningThread = Thread.currentThread();
}
openServerSocket();
while (!isStopped()) {
Socket clientSocket = null;
try {
clientSocket = this.serverSocket.accept();
clients.add(clientSocket);
} catch (IOException e) {
if (isStopped()) {
Log.d("SERVER TEXT", "Server Stopped.");
return;
}
throw new RuntimeException(
"Error accepting client connection", e);
}
new Thread(new WorkerRunnable(clientSocket, this)).start();
}
Log.d("SERVER TEXT", "Server Stopped.");
}
private synchronized boolean isStopped() {
return this.isStopped;
}
public synchronized void stop() {
this.isStopped = true;
try {
this.serverSocket.close();
} catch (IOException e) {
throw new RuntimeException("Error closing server", e);
}
}
private void openServerSocket() {
try {
this.serverSocket = new ServerSocket(this.serverPort);
} catch (IOException e) {
throw new RuntimeException("Cannot open port 8080", e);
}
}
private void broadcastMessage(String message) {
for (int i = 0, j = clients.size(); i <= j; i++) {
PrintWriter out = null;
Socket socket = clients.get(i);
try {
out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// WHERE YOU ISSUE THE COMMANDS
out.println(message);
Log.d("SERVER Loop", "Broadcasting messages...");
out.close();
}
Log.d("SERVER", "Message Brodcasted");
}
}
public class WorkerRunnable implements Runnable {
protected Socket clientSocket = null;
protected String mMsgFromClient = null;
private UUID id;
public WorkerRunnable(Socket clientSocket, MultiThreadedServer server) {
this.clientSocket = clientSocket;
id = UUID.randomUUID();
}
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(
clientSocket.getInputStream()));
while ((mMsgFromClient = in.readLine()) != null) {
handler.post(new Runnable() {
#Override
public void run() {
serverStatus.append('\n'
+ "Message From Client ID " + getID()
+ ": " + mMsgFromClient);
}
});
}
Log.d("SERVERTEXT", "Proceed to broadcast");
server.broadcastMessage(mMsgFromClient);
} catch (IOException e) {
Handler handler = new Handler();
handler.post(new Runnable() {
#Override
public void run() {
serverStatus
.append('\n'
+ "Message From Client ID "
+ getID()
+ ": "
+ "Oops. Connection interrupted. Please reconnect your phones.");
}
});
e.printStackTrace();
}
}
private String getID() {
return id.toString();
}
}
}
Here is the full code for the Client class
public class Client extends Activity {
private EditText serverIp;
private EditText chatMsg;
private Button connectPhones;
private Button sendMsg;
private TextView msgFromOtherClients;
private String serverIpAddress = "";
private boolean connected = false;
private boolean willSendMsg = false;
private Handler handler = new Handler();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.client);
serverIp = (EditText) findViewById(R.id.server_ip);
connectPhones = (Button) findViewById(R.id.connect_phones);
connectPhones.setOnClickListener(connectListener);
chatMsg = (EditText) findViewById(R.id.chat_msg);
sendMsg = (Button) findViewById(R.id.send_msg);
sendMsg.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
willSendMsg = true;
}
});
msgFromOtherClients = (TextView) findViewById(R.id.msg_from_other_clients);
}
private OnClickListener connectListener = new OnClickListener() {
#Override
public void onClick(View v) {
if (!connected) {
serverIpAddress = serverIp.getText().toString();
if (!serverIpAddress.equals("")) {
Thread cThread = new Thread(new ClientThread());
cThread.start();
}
}
}
};
public class ClientThread implements Runnable {
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
Log.d("ClientActivity", "C: Connecting...");
Socket socket = new Socket(serverAddr, Server.SERVERPORT);
connected = true;
Thread listener = new Thread(new ClientThreadListener(new Socket(serverAddr, Server.SERVERPORT)));
listener.start();
while (connected) {
if (willSendMsg) {
willSendMsg = false;
try {
Log.d("ClientActivity", "C: Sending command.");
PrintWriter out = new PrintWriter(
new BufferedWriter(new OutputStreamWriter(
socket.getOutputStream())), true);
// WHERE YOU ISSUE THE COMMANDS
out.println(chatMsg.getText().toString());
Log.d("ClientActivity", "C: Sent.");
} catch (Exception e) {
Log.e("ClientActivity", "S: Error", e);
}
}
}
socket.close();
Log.d("ClientActivity", "C: Closed.");
} catch (Exception e) {
Log.e("ClientActivity", "C: Error", e);
connected = false;
}
}
}
public class ClientThreadListener implements Runnable {
protected Socket serverSocket = null;
protected String mMsgFromServer;
public ClientThreadListener(Socket serverSocket) {
this.serverSocket = serverSocket;
}
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(
serverSocket.getInputStream()));
while ((mMsgFromServer = in.readLine()) != null) {
Log.d("MESSAGE FROM SERVER: ", mMsgFromServer);
handler.post(new Runnable() {
#Override
public void run() {
msgFromOtherClients.append('\n'
+ "Message From Server: " + mMsgFromServer);
}
});
}
} catch (Exception e) {
Log.e("ClientListener", "C: Error", e);
connected = false;
}
}
}
}
Your code has some issue that prevents it from working.
As already said in other answers, in your code you are closing the socket output stream right after sending the message to the client. call close() only out of your for message loop. Of course closing the socket in the client will have the same effect as closing it on the server. You must close the sockets only when client and server have finished talking. Closing it while transmitting data it's like hanging up the phone in the middle of a conversation.
Second, you create a new socket on the client side:
Log.d("ClientActivity", "C: Connecting...");
Socket socket = new Socket(serverAddr, Server.SERVERPORT);
but then you pass to the listener another, newly created, socket (I suppose this is not intended):
connected = true;
Thread listener = new Thread(new ClientThreadListener(new Socket(serverAddr, Server.SERVERPORT)));
listener.start();
Third, always call flush() on an output stream right after sending data, or the data will likely not be sent (the send methods will just enqueue your data in the sending buffer).
Last (This may not be useful to you since I don't know your ultimate goal), if you need to send and receive on sockets, 90% of the time it's better and easier to do this asinchronously, using separate threads for listening and sending.
If it still doesn't work, add here some output or log trace from logcat.
You need to move the line:
server.broadcastMessage(mMsgFromClient);
inside the while:
while ((mMsgFromClient = in.readLine()) != null) {
handler.post(new Runnable() {
#Override
public void run() {
serverStatus.append('\n'
+ "Message From Client ID " + getID()
+ ": " + mMsgFromClient);
}
});
// HERE
Log.d("SERVERTEXT", "Proceed to broadcast");
server.broadcastMessage(mMsgFromClient);
}
Otherwise, you'll only broadcast null.
EDIT: You should make sure that mMsgFromClient is not changed between posting the new Runnable and it actually executing. The best way is to initialize a field in the anonymous class with the current value, and log the value of that field instead.
EDIT2: Unless your server is supposed to close its connection to a client after sending it a broadcast message, you should use out.flush() instead of out.close() in the broadcastMessage method. It's preferrable that client connections are closed after a timeout, or just let the clients disconnect, again with a timeout.
Otherwise, your test will be very limited most of the times: a client connects and sends a message; then it receives its own message and the server closes the connection.
Please try to use AsyncTask in android which will create separate thread for communication with server.