Develop Reference

client can't send message from separate class

I created a socket program on android studio. First I create it with on the main class and it is working. With the help of this site I separate the connect and disconnect it works. Now there is a problem when the client send a message on the server. Whenever I put a letter, the output is just a blank space.
separate class
public class SocketClient extends Thread {
String serverm = null;
Socket client;
String Socketdata;
Context context;
String message;
String address;
public boolean mRun = true;
private PrintWriter printwriter;
public SocketClient (String address, Context context, String message )
{
this.address = address;
this.context = context;
this.message = message;
}
#Override
public void run(){
mRun = true;
try {
client = new Socket(address, 3818);
BufferedReader mBufferIn = new BufferedReader(
new InputStreamReader(client.getInputStream()));
while (mRun) {
serverm = mBufferIn.readLine();
if (serverm != null) {
System.out.println(serverm);
Socketdata = serverm;
}
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public void stopSocket()
{
if(client !=null)
{
Toast.makeText(context, "disconnected", Toast.LENGTH_LONG).show();
try {
client.close();
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else{
Toast.makeText(context, "socket not found", Toast.LENGTH_LONG).show();
}
}
public void SendSocket()
{
if (message != null) {
try {
printwriter = new PrintWriter(client.getOutputStream(),true);
printwriter.write(message + "\r\n"); // write the message to output stream
printwriter.flush();
}catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
Toast.makeText(context, "sent", Toast.LENGTH_LONG).show();
}
}
Main class
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textField = (EditText) findViewById(R.id.message); // reference to the text field
Connect = (Button) findViewById(R.id.connect); // reference to the connect button
Disconnect = (Button) findViewById(R.id.disconnect); // reference to the connect button
Send = (Button) findViewById(R.id.send); // reference to the send button
editTextAddress = (EditText) findViewById(R.id.address); // reference to the address
Disconnect.setOnClickListener(DisconnectOnClickListener);
Connect.setOnClickListener(ConnectOnClickListener);
Send.setOnClickListener(SendOnClickListener);
}
//Button Send
OnClickListener SendOnClickListener = new OnClickListener() {
public void onClick(View v) {
thread.SendSocket();
textField.setText(""); // Reset the text field to blank
}
};
//Button Disconnect
OnClickListener DisconnectOnClickListener = new OnClickListener() {
public void onClick(View v) {
thread.stopSocket();
}
};
//Button Connect
OnClickListener ConnectOnClickListener = new OnClickListener() {
public void onClick(View v) {
Toast.makeText(getApplicationContext(),"connected",Toast.LENGTH_LONG).show();
thread = new SocketClient(editTextAddress.getText().toString(), getApplicationContext(), textField.getText().toString());
thread.start();
}
};

Now I know what I'm missing. sorry for the inconvenience.
separate class
public void SendSocket(String newMessage ) {
if (newMessage != null) {
try {
printwriter = new PrintWriter(socket.getOutputStream(),true);
printwriter.write(newMessage + "\r\n"); // write the message to output stream
printwriter.flush();
}catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
main class
View.OnClickListener SendOnClickListener = new View.OnClickListener() {
public void onClick(View v) {
thread.SendSocket(textField.getText().toString());
}
};

Connecting 2 android devices over internet

I'm trying to connect 2 android device (without server in the middle, just directly like peer-to-peer) which are connected to internet(they are far apart) and send messages.
I thought its like normal socket programming, and connects via IP, seems not.
what I have done so far is this:
I have created 2 android projects, server(receiver) and client(sender)
running in 2 separate devices
Both devices are connected to internet
found the IP of the device with server app running in (using whatismyip.com)
and used it in client app code
but when I want to send a text from client to server, an exception happens in client printing Error3
this is my code:
server:
public class MainActivity extends Activity {
ServerSocket ss = null;
String mClientMsg = "";
Thread myCommsThread = null;
protected static final int MSG_ID = 0x1337;
public static final int SERVERPORT = 6000;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView tv = (TextView) findViewById(R.id.TextView01);
tv.setText("Nothing from client yet");
this.myCommsThread = new Thread(new CommsThread());
this.myCommsThread.start();
}
#Override
protected void onStop() {
super.onStop();
try {
// make sure you close the socket upon exiting
ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
Handler myUpdateHandler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_ID:
TextView tv = (TextView) findViewById(R.id.TextView01);
tv.setText(mClientMsg);
break;
default:
break;
}
super.handleMessage(msg);
}
};
class CommsThread implements Runnable {
public void run() {
Socket s = null;
try {
ss = new ServerSocket(SERVERPORT );
} catch (IOException e) {
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted()) {
Message m = new Message();
m.what = MSG_ID;
try {
if (s == null)
s = ss.accept();
BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
String st = null;
st = input.readLine();
mClientMsg = st;
myUpdateHandler.sendMessage(m);
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
Client (Error3):
public class MainActivity extends Activity {
private Button bt;
private TextView tv;
private Socket socket;
private String serverIpAddress = "5.114.22.118";
// AND THAT'S MY DEV'T MACHINE WHERE PACKETS TO
// PORT 5000 GET REDIRECTED TO THE SERVER EMULATOR'S
// PORT 6000
private static final int REDIRECTED_SERVERPORT = 80;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bt = (Button) findViewById(R.id.myButton);
tv = (TextView) findViewById(R.id.myTextView);
new Thread(new ClientThread()).start();
bt.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
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);
Log.d("Client", "Client sent message");
} catch (UnknownHostException e) {
tv.setText("Error1");
e.printStackTrace();
} catch (IOException e) {
tv.setText("Error2");
e.printStackTrace();
} catch (Exception e) {
tv.setText("Error3");
e.printStackTrace();
}
}
});
}
class ClientThread implements Runnable {
#Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
socket = new Socket(serverAddr, REDIRECTED_SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}

I think this would be more appropriate as a comment, but I don't have enough reputation to comment so I'm providing it as an answer. Is your server connected to a router? whatismyip.com returns the IP address of the router, not the device.

Message not received from Python to Android with socket

my android application needs to communicate with a server python but at the time to receive a response, the answer does not come. These are my codes:
This is my Client:
public class MainActivity extends Activity {
private Socket socket;
private static final int SERVERPORT = 5589;
private static final String SERVER_IP = "192.168.1.131";
TextView risp;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
risp = (TextView) findViewById(R.id.textView1);
new Thread(new ClientThread()).start();
}
public void onClick(View view) {
try {
EditText et = (EditText) findViewById(R.id.editText1);
String str = et.getText().toString();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
out.println(str);
out.flush();
// Read from sock
BufferedReader input = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
StringBuilder response = new StringBuilder();
String line;
while ((line = input.readLine()) != null) {
response.append(line);
}
risp.setText(risp.getText().toString() + " " + response.toString());
out.close();
input.close();
socket.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 {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
And this is the Server:
import socket
import sys
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Bind the socket to the port
server_address = ('192.168.1.131', 5589)
print >>sys.stderr, 'starting up on %s port %s' % server_address
sock.bind(server_address)
# Listen for incoming connections
sock.listen(1)
while True:
# Wait for a connection
print >>sys.stderr, 'waiting for a connection'
connection, client_address = sock.accept()
try:
print >>sys.stderr, 'connection from', client_address
# Receive the data
while True:
data = connection.recv(1024)
if data.lower() != 'q':
print "<-- client: ", data
else:
print "Quit from Client"
connection.close()
break
data = raw_input("--> server: ")
if data.lower() != 'q':
connection.sendall(data)
else:
print "Quit from Server"
connection.close()
break
finally:
# Clean up the connection
print "Connection close"
connection.close()
The server receive the client message, but the client doesn't receive the server message. Why?
Thanks all in advance
EDIT: I SOLVED it this way:
public class MainActivity extends Activity {
private Socket socket;
private static final int SERVERPORT = 5589;
private static final String SERVER_IP = "192.168.1.131";
TextView risp;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
risp = (TextView) findViewById(R.id.textView1);
new Thread(new ClientThread()).start();
}
public void onClick(View view) {
new ConnectionTask().execute();
}
class ConnectionTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
String responce = null;
try {
EditText et = (EditText) findViewById(R.id.editText1);
String str = et.getText().toString();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
out.println(str);
out.flush();
InputStream input = socket.getInputStream();
int lockSeconds = 10*1000;
long lockThreadCheckpoint = System.currentTimeMillis();
int availableBytes = input.available();
while(availableBytes <=0 && (System.currentTimeMillis() < lockThreadCheckpoint + lockSeconds)){
try{Thread.sleep(10);}catch(InterruptedException ie){ie.printStackTrace();}
availableBytes = input.available();
}
byte[] buffer = new byte[availableBytes];
input.read(buffer, 0, availableBytes);
responce = new String(buffer);
out.close();
input.close();
socket.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return responce;
}
protected void onPostExecute(String responce) {
risp.setText(responce);
}
}
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();
}
}
}
}

Android client sends only one message to java server

I am developing a simple chat application. Android client and a java desktop server. I am facing a problem that my client sends only a single message to server. Server code is working on java client so only android code have some problem.
Android Client
private static final int SERVERPORT = 5000;
private static final String SERVER_IP = "10.0.2.2";
private Socket socket;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread(new ClientThread()).start();
Button button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
EditText et = (EditText) findViewById(R.id.editText1);
public void onClick(View v) {
try {
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
String str = et.getText().toString();
out.println(str);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException 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();
}
}
}

That is because your thread finishes its job and it's no longer available for you.

How to stop Socket to send a lot of useless data when closed?

I use these codes for communicating between devices. If i close or kill the client app, the server app gets thousands of useless data. The textView in the server side is full of this: Client says: null. If i close the client twice, the server stops with StackOverFlowError. How can i make the code to dont send this null values when the app stops? Or can i filter the server side to do nothing when getting this data?
Client:
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();
}
}
}
}
Server:
public class Server extends Activity {
private ServerSocket serverSocket;
Handler updateConversationHandler;
Thread serverThread = null;
private TextView text;
public static final int SERVERPORT = 1599;
#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");
}
}
}

I think you should use a delimiter character, to tell the Server your Client it's about to die. Add that character of code in onPause method of your Android Activity/Fragment.
Then in your Server, just get the String or byte and compare it against your Delimiter String/Character and stop the Server listening for the Connection.

while (!Thread.currentThread().isInterrupted()) {
try {
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
The problem is here. You aren't checking the result of readLine() for null. If it returns null, the peer has closed the connection and you should do likewise, and exit this loop. You can probably get rid of the isInterrupted() test as well.
Also, if you get any IOException other that a read timeout when reading from a socket, the connection is dead and you must close the socket and exit your loop.