I'm building a very small app to send data from the cellphone to a computer. I've read a couple of examples and got the server and client code working. But when i try to connect them, got a "network unreachable" error. Any idea what am i doing wrong??
This is the Server Code:
import java.net.*;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.*;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Server {
static BufferedReader in = null;
static Socket clientSocket = null;
static ServerSocket serverSocket = null;
public static void main(String[] args) throws IOException {
JFrame frame = new JFrame("FrameDemo");
frame.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
try {
if (in != null)
in.close();
if (serverSocket.isClosed())
{}
else
serverSocket.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
});
JLabel Label = new JLabel("");
Label.setPreferredSize(new Dimension(175, 100));
frame.getContentPane().add(Label, BorderLayout.CENTER);
//Display the window.
frame.pack();
frame.setVisible(true);
Label.setText("Empezo");
serverSocket = null;
try {
serverSocket = new ServerSocket(4444);
} catch (IOException e) {
System.err.println("Could not listen on port: 4444.");
System.err.println(e.getMessage());
System.exit(1);
}
Integer puerto = serverSocket.getLocalPort();
Label.setText("<html>Puerto Abierto: " + puerto.toString() + "<br>IP Servidor: " + serverSocket.getInetAddress().toString() + "</html>");
clientSocket = null;
try {
clientSocket = serverSocket.accept();
Label.setText("Conection Accepted");
} catch (IOException e) {
System.err.println("Accept failed.");
System.exit(1);
}
in = new BufferedReader(
new InputStreamReader(
clientSocket.getInputStream()));
while ((in.readLine()) != null) {
System.out.println("Mensaje: " + in.readLine());
}
}
}
And the Cliente part
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
public class PruebaSocket extends Activity {
/** Called when the activity is first created. */
Socket Skt;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button Enviar =(Button)findViewById(R.id.OK);
Button Salir = (Button)findViewById(R.id.SALIR);
final TextView IP = (TextView)findViewById(R.id.IP);
Skt = new Socket();
Enviar.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
try{
Skt = new Socket("192.168.1.101",4444);
CharSequence errorMessage = "Coneccted";
Toast.makeText(PruebaSocket.this, errorMessage, Toast.LENGTH_SHORT).show();
}
catch(Exception E)
{
CharSequence errorMessage = E.getMessage();
Toast.makeText(PruebaSocket.this, errorMessage, Toast.LENGTH_SHORT).show();
if (Skt.isConnected())
try {
Skt.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
});
Salir.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View arg0) {
try {
Skt.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
);
}
}
192.168.1.101 it's the IP of the server.
I don't know much about java sockets but the normal usage of a socket is: create, bind, and put in listen mode (udp) or call .accept() (tcp). I can see Java also has the binding phase - http://download.oracle.com/javase/1.5.0/docs/api/java/net/ServerSocket.html#bind(java.net.SocketAddress, int).
Related
I have a working messaging app that sends messages from the client to the server.
I want the client to CONSTANTLY listen for messages from the server.
I want the client to only send packets to the server when "Start" is called, but the problem is that I have to press it twice for the message to actually deliver to the server (Idk why)
Later on I'll change the program to something that always delivers messages to the server (his GPS location), so I would also like some tips about how to make a loop in an Android app.
//Client
package com.example.clienttest;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity {
Thread m_objThreadClient;
Socket clientSocket;
TextView serverMessage;
EditText clientMessage;
String sIn, sOut;
BufferedReader brOut, brIn;
DataOutputStream oos;
DataInputStream ois;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
serverMessage = (TextView) findViewById(R.id.textView1);
clientMessage = (EditText) findViewById(R.id.editText1);
m_objThreadClient = new Thread( new Runnable(){
public void run()
{
try {
clientSocket = new Socket("192.168.1.102", 4000);
oos = new DataOutputStream (clientSocket.getOutputStream());
ois = new DataInputStream (clientSocket.getInputStream());
brIn = new BufferedReader (new InputStreamReader(ois));
} catch (IOException e) {
serverMessage.setText(e.getMessage());
}
}
});
m_objThreadClient.start();
}
public void Listener(){
try {
while ((sIn = brIn.readLine()) != null){
sIn = brIn.readLine();
}
serverMessage.setText(sIn);
} catch (IOException e) {
serverMessage.setText(e.getMessage());
}
}
public void Start(View view) {
sOut = clientMessage.getText().toString();
try {
oos.writeUTF(sOut);
oos.flush();
oos.flush();
} catch (IOException e) {
serverMessage.setText(e.getMessage());
}
}
public void onStop(){
try {
oos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
//Server
import java.net.ServerSocket;
import java.net.Socket;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.PrintWriter;
import java.util.Hashtable;
public class Server2 {
#SuppressWarnings("resource")
public static void main (String[] args) throws IOException {
ServerSocket server = null;
try {
server = new ServerSocket(4000);
} catch (IOException e) {
System.err.println("Could not start up on: " + "4000" + "Maby server is already open? Or a portforwording messup?");
System.err.println(e);
System.exit(1);
}
Socket client = null;
while(true) {
try {
client = server.accept();
System.out.print("Connected ");
} catch (IOException e) {
System.err.println("Accept failed.");
System.err.println(e);
}
Thread t = new Thread(new ClientConn(client));
t.start();
}
}
}
class ClientConn implements Runnable {
private Socket client;
String Recv;
DataInputStream inFromClient;
DataOutputStream outToClient;
ClientConn(Socket client) {
this.client = client;
try {
inFromClient = new DataInputStream(client.getInputStream());
outToClient = new DataOutputStream(client.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
String response;
try {
while ((response = inFromClient.readUTF()) != null) {
Recv = inFromClient.readUTF();
System.out.print("Msg: " + Recv + " \n");
if( Recv.equals("Hi")){
outToClient.writeUTF("Wa alaikum");
outToClient.flush();
}
else{
outToClient.writeUTF("..what?");
outToClient.flush();
}
}
} catch (IOException e) {
System.out.print("No input ");
System.err.println(e);
}
}
}
I want to connect to my server building in Android, but I can't, I don't know how to connect it. I think my code is fine. I changed Manifest with Permission INTERNET.
package com.android.server;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity implements OnClickListener{
/** Called when the activity is first created. */
private static String TAG = "ServerSocketTest";
EditText edittext1;
private ServerSocket server;
Runnable conn = new Runnable() {
public void run() {
try {
edittext1.setText("Esperando0");
server = new ServerSocket(9999);
edittext1.setText("Esperando1");
while (true) {
edittext1.setText("Esperando2");
Socket socket = server.accept();
if(socket.isConnected() == true){
edittext1.setText("socket is connected: " + socket.getRemoteSocketAddress().toString());
}
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String str = in.readLine();
Toast.makeText(getApplicationContext(), "BufferedReader ready", Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(), str, Toast.LENGTH_SHORT).show();
Log.i("received response from server", str);
edittext1.setText("Conectado");
PrintWriter salida = new PrintWriter(new OutputStreamWriter( socket.getOutputStream() ),true );
salida.println("Conexion establecida");
in.close();
socket.close();
}
} catch (IOException e) {
Log.e(TAG, e.getMessage());
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
}
};
#SuppressLint({ "NewApi", "NewApi", "NewApi", "NewApi" })
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
edittext1 = (EditText)findViewById(R.id.editText1);
Button boton1 = (Button)findViewById(R.id.button1);
boton1.setOnClickListener(this);
new Thread(conn).start();
}
#Override
protected void onPause() {
super.onPause();
if (server != null) {
try {
server.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void onClick(View v) {
}
}
My client, it work very well.:
package com.clientesocketandroid;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class ClienteSocketAndroid extends Activity implements OnClickListener{
String IP,mensaje, MensajeEntrada;
int Port;
Socket socket;
ServerSocket SSocket;
PrintWriter out;
Button boton1, boton2,boton3;
EditText edittext1,edittext2,edittext3,edittext4;
TextView textview5;
String mClientMsg = "";
Thread myCommsThread = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cliente_socket_android);
boton1 = (Button)findViewById(R.id.button1);
boton1.setOnClickListener(this);
boton2 = (Button)findViewById(R.id.button2);
boton2.setOnClickListener(this);
boton3 = (Button)findViewById(R.id.button3);
boton3.setOnClickListener(this);
edittext1 = (EditText)findViewById(R.id.editText1);
edittext2 = (EditText)findViewById(R.id.editText2);
edittext3 = (EditText)findViewById(R.id.editText3);
edittext4 = (EditText)findViewById(R.id.editText4);
Port = Integer.parseInt(edittext3.getText().toString());
try {
SSocket = new ServerSocket(Port);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
socket = SSocket.accept();
Toast.makeText(getApplicationContext(), "Listo", Toast.LENGTH_SHORT).show();
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
MensajeEntrada = in.readLine();
edittext4.setText(MensajeEntrada);
} catch (Exception e) {
e.printStackTrace();
}
}
#SuppressLint({ "NewApi", "NewApi", "NewApi" })
public void onClick(View arg0) {
if(arg0.getId() == R.id.button1){
try {
IP = edittext2.getText().toString();
Port = Integer.parseInt(edittext3.getText().toString());
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
socket = new Socket(IP, Port); //Abre un socket con el número de IP y de puerto.
if(socket.isConnected() == true){
Toast.makeText(getApplicationContext(), "Conectado", Toast.LENGTH_SHORT).show();
}
} catch (UnknownHostException e) {
e.printStackTrace();
edittext1.setText(e.getMessage() + ": " + e.getCause());
} catch (IOException e) {
e.printStackTrace();
edittext1.setText(e.getMessage() + ": " + e.getCause());
}
}
if(arg0.getId() == R.id.button3){
try {
mensaje = edittext1.getText().toString();
PrintWriter salida = new PrintWriter(new OutputStreamWriter( socket.getOutputStream() ),true );
salida.println(mensaje);
edittext1.setText("");
//hace falta concatenacion
edittext4.setText("" + "\n" + mensaje + "");
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), "Mensaje NO enviado", Toast.LENGTH_SHORT).show();
}
}
if(arg0.getId() == R.id.button2){
try {
PrintWriter salida = new PrintWriter(new OutputStreamWriter( socket.getOutputStream() ),true );
salida.println("bye");
Toast.makeText(getApplicationContext(), "Conexión cerrada", Toast.LENGTH_SHORT).show();
socket.close();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), "Error al cerrar sesion", Toast.LENGTH_SHORT).show();
}
}
}
}
I thank your Help!!
The algorithm shows that whenever your socket is connected or not, you always create a buffered i/O stream and sending the data
The following is my suggested pseudo code for server
try(socket successfully connected) {
try( server is synchronized with the client) socket.accept();
// create the Object I/O stream
} show error
for Client
//Create a new socket with IP address and port number
try
client connect to server with aforementioned parameters with timeout
create a Object I/O stream
catch (IOException)
One problem that I see with your code is, you cannot update Ui elements from Non Ui thread, that is why it is raising exception, but you have caught all the exceptions.
So remove all setText calls from the runnable.
edittext1.setText("Conectado");
Use runonUithread or any other methods to update UI elements, and do not catch all exceptions like you have done. It is quite difficult to debug.
I have problem with android sockets , I have two android applications Server and ServerClient , in ServerClient It gives nullPointerException on second row written below
InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
socket = new Socket(serverAddr, REDIRECTED_SERVERPORT);
I checked serverAddr is 10.0.2.2 , but then I saw that socket is null. Can anybody helps with it?
EDIT: with this serverAddress I saw that it is unreachable, maybe I must make it reachable manual ?
here is sources
*ServerClient*
package com.example.serverclient;
import android.os.Bundle;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import android.app.Activity;
import android.util.Log;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.view.View;
import android.view.Menu;
public class MainActivity extends Activity {
private Button bt;
private TextView tv;
private Socket socket;
private String serverIpAddress = "10.0.2.2";
private static final int REDIRECTED_SERVERPORT = 5000;
// AND THAT'S MY DEV'T MACHINE WHERE PACKETS TO
// PORT 5000 GET REDIRECTED TO THE SERVER EMULATOR'S
// PORT 6000
#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);
try {
InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
socket = new Socket(serverAddr, REDIRECTED_SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
bt.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
try {
EditText et = (EditText) findViewById(R.id.EditText01);
String str = et.getText().toString();
OutputStream sk = socket.getOutputStream();
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();
}
}
});
}
}
**Server**
package com.example.myserver;
import android.os.Bundle;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.widget.TextView;
import android.app.Activity;
import android.view.Menu;
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();
}
}
}
}
}
Have you made sure that you aren't getting an UnknownHostException or a IOException? One of those has to be getting called otherwise socket would not be null.
Change (Exception e) of the error 3 para to NullPointerException and then run the client side and send a message. Error 3 will no longer be displayed on the screen and you will receive the message on Myserver.
Exception e --> NullPointerException
This class returns your response, but also needs permission of internet in manifest file.
public class ChatApplication extends Application {
private Socket mSocket;
{
try {
mSocket = IO.socket("http://chat.socket.io");
} catch (URISyntaxException e) {
throw new RuntimeException(e);
}
}
public Socket getSocket() {
return mSocket;
}
}
I've finally managed to connect from my android phone to my device, put I have a problem when I try to read from my bluetooth socket.
So here is my code for establishing connecting to my device, its a class that extends AsyncTask
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import android.app.ProgressDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Button;
import android.widget.Toast;
public class Connect extends AsyncTask<String, Void, String> {
private final static String TAG = "+++CONNECT THREAD+++";
ProgressDialog progressDialog;
Context context;
BluetoothSocket tmp;
BluetoothDevice device;
BluetoothAdapter ba;
Button connect;
int bt_port_to_connect;
ReadInput ri;
InputStream is;
byte[] test;
public Connect(Context context, BluetoothDevice device, BluetoothAdapter ba, Button connect) {
this.ba = ba;
this.context = context;
this.device = device;
this.connect = connect;
bt_port_to_connect = 9;
}
protected void onPreExecute() {
progressDialog=ProgressDialog.show(context,"Please Wait..","Connecting to device",false);
}
#Override
protected String doInBackground(String... arg0) {
Method m = null;
try {
m = device.getClass().getMethod("createInsecureRfcommSocket", new Class[] {int.class});
} catch (NoSuchMethodException e1) {
e1.printStackTrace();
}
try {
tmp = (BluetoothSocket) m.invoke(device, bt_port_to_connect);
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
ba.cancelDiscovery();
tmp.connect();
ri = new ReadInput(tmp);
ri.start();
} catch (IOException e) {
Log.e("+++CONNECT1+++","EXCEPTION: " + e.getMessage());
try {
tmp.close();
} catch (IOException e2) {
Log.e(TAG, "unable to close() " + " insecure socket type" +
" socket during connection failure", e2);
}
Log.e("+++CONNECT2+++", e.getLocalizedMessage());
}
boolean isConnected = tmp.isConnected();
if(isConnected) {
return "connected";
}
else {
return "notConnected";
}
}
protected void onPostExecute(String result) {
progressDialog.dismiss();
if(result.equals("connected")) {
connect.setEnabled(false);
Toast.makeText(context, "Connected to device: "+device.getName().toString(), Toast.LENGTH_LONG).show();
//new ReadIn(context, tmp).execute("");
}
else if(result.equals("notConnected")) {
Toast.makeText(context, "Can`t reach host", Toast.LENGTH_LONG).show();
}
}
}
As you can see, the line below tmp.connect(); I create a new object of a new class, this is the class which I want to handle the reading of the inputStream So here is the code for that class:
import java.io.IOException;
import java.io.InputStream;
import android.bluetooth.BluetoothSocket;
import android.util.Log;
public class ReadInput extends Thread {
BluetoothSocket socket;
private InputStream is;
public ReadInput(BluetoothSocket socket) {
Log.i("READINPUT", "INSIDE READ INPUT THREAD CONSTRUCTOR!!!");
InputStream tmpIn = null;
this.socket = socket;
is = null;
try {
tmpIn = socket.getInputStream();
} catch (IOException e) {
Log.e("READINPUT", "Temp socket in created: " + e.getMessage());
}
is = tmpIn;
}
public void run() {
Log.i("READINPUT", "INSIDE READ INPUT THREAD RUN METHOD!!!");
byte[] buffer = new byte[1024];
int bytes = 0;
while(true) {
try {
bytes = is.read(buffer);
} catch (IOException e) {
Log.e("FROM RUN METHOD: ", e.getMessage());
}
Log.i("INPUTSTREAM GOT: ", Integer.toString(bytes));
}
}
}
I have two Log.i methods in my last code, this outputs the correct info to LogCat stating where in the code I am. But it doesnt output the content of the stream to LogCat. What am I doing wrong here? Yes, I've looked into the BluetoothChat example.
Thanks in advance!
EDIT 1
I've done some research in the constructor of the ReadInput Class.
is = tmpIn;
try {
Log.i("InputStream: ", Integer.toString(is.available()));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
This snippet will only output to logcat that is returns 0 which means that the InputStream is not available. Any suggestions?
I found using a buffered reader works well with a blietooth device. And then I just used a while.loop with br.isReady in a while true listener. Basically makes a "listener"
I am testing socket programming on Android however I am having a problem. The client is basically launched through the main activity with a basic function of sending a message to the server and getting a reply.
the client activity:
package com.test.socket;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class socketActivity extends Activity implements OnClickListener {
String input;
private EditText et;
private ObjectOutputStream oos;
private TextView tv;
private String message;
private ObjectInputStream ois;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try{
InetAddress host = InetAddress.getLocalHost();
Socket socket = new Socket(host.getHostName(),7777);
//send to server
oos = new ObjectOutputStream(socket.getOutputStream());
et = (EditText) findViewById(R.id.text);
Button sendButton = (Button) findViewById(R.id.button);
sendButton.setOnClickListener(this);
//read from server
ois = new ObjectInputStream(socket.getInputStream());
//System.out.println("Message from Server: "+message);
tv = (TextView) findViewById(R.id.textView);
}
catch(UnknownHostException e)
{
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch(v.getId())
{
case R.id.button:
input = et.getText().toString();
try {
oos.writeObject(input);
ois.close();
oos.close();
message = (String) ois.readObject();
tv.setText("Message from Server: "+message);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
break;
}
}
}
The Server class launched separately from JCreator listening to port 7777:
import java.io.*;
import java.lang.*;
import java.net.*;
public class server {
private ServerSocket server;
private int port = 7777;
public server()
{
try{
server = new ServerSocket(port);
}
catch(IOException e)
{
e.printStackTrace();
}
}
public static void main(String args[])
{
server example = new server();
example.handleConnection();
}
public void handleConnection()
{
System.out.println("Waiting for client message...");
while(true)
{
try{
Socket socket = server.accept();
new ConnectionHandler(socket);
}
catch(IOException e)
{
e.printStackTrace();
}
}
}
}
ConnectionHandler class which the Server accesses:
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
public class ConnectionHandler implements Runnable {
private Socket socket;
public ConnectionHandler(Socket socket)
{
this.socket = socket;
Thread t = new Thread(this);
t.start();
}
#Override
public void run() {
// TODO Auto-generated method stub
try{
//receive from client
ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
String message = (String) ois.readObject();
System.out.println("Message from client: "+message);
if(message.equals("check"))
{
System.out.println("Checking for malicious interference...");
Thread.sleep(5000);
System.out.println("Status: Files are good.");
}
//send response to client
ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
if(message.equals("check"))
{
oos.writeObject("Checking...");
}
else oos.writeObject("Invalid input");
ois.close();
oos.close();
socket.close();
System.out.println("Waiting for client message...");
}
catch(IOException e)
{
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
I have tested the code on JCreator and Eclipse through Java application not Android app and it worked perfect. However when I try doing it through the activity, it's not working.
Any ideas?
In Android, localhost would point to the phone/emulator itself. It doesn't point to your server. The following line below is pointing to your Android device/emulator and not your server. You need to get the actual IP of the server to get it working from your Android
InetAddress host = InetAddress.getLocalHost();
Socket socket = new Socket(host.getHostName(),7777);
It works through Java App, because when you execute it from the context of Java Application, the localhost is pointing to the same server location.