I have two android tablets that I want to send messages from the client to the server with socket programming. I pasted the sample code to make the server and client apps and installed them on two android tablets. both connected to wifi
on the client app there is an edit text that i am supposed to type in an IP address in it then the button below that is called “connect phones”.
what IP address am i supposed to type in the edittext before clicking the “connect phones button”
here is the onclick listener for the “connect phones” button
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();
}
}
}
};
full code for both client and server apps shown below;
client code:
package com.example.client;
// import statements
public class ClientActivity extends Activity {
private EditText serverIp;
private Button connectPhones;
private String serverIpAddress = "";
private boolean connected = 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);
}
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, 8080);
connected = true;
while (connected) {
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("Hey Server!");
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;
}
}
}
}
server code;
package com.example.server;
// import statements
public class ServerActivity 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;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.server);
serverStatus = (TextView) findViewById(R.id.server_status);
SERVERIP = getLocalIpAddress();
Thread fst = new Thread(new ServerThread());
fst.start();
}
public class ServerThread implements Runnable {
public void run() {
try {
if (SERVERIP != null) {
handler.post(new Runnable() {
@Override
public void run() {
serverStatus.setText("Listening on IP: " + SERVERIP);
}
});
serverSocket = new ServerSocket(SERVERPORT);
while (true) {
// listen for incoming clients
Socket client = serverSocket.accept();
handler.post(new Runnable() {
@Override
public void run() {
serverStatus.setText("Connected.");
}
});
try {
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
String line = null;
while ((line = in.readLine()) != null) {
Log.d("ServerActivity", line);
handler.post(new Runnable() {
@Override
public void run() {
// do whatever you want to the front end
// this is where you can be creative
}
});
}
break;
} catch (Exception e) {
handler.post(new Runnable() {
@Override
public void run() {
serverStatus.setText("Oops. Connection interrupted. Please reconnect your phones.");
}
});
e.printStackTrace();
}
}
} else {
handler.post(new Runnable() {
@Override
public void run() {
serverStatus.setText("Couldn't detect internet connection.");
}
});
}
} catch (Exception e) {
handler.post(new Runnable() {
@Override
public void run() {
serverStatus.setText("Error");
}
});
e.printStackTrace();
}
}
}
// gets the ip address of your phone's network
private String getLocalIpAddress() {
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();
if (!inetAddress.isLoopbackAddress()) { return inetAddress.getHostAddress().toString(); }
}
}
} catch (SocketException ex) {
Log.e("ServerActivity", ex.toString());
}
return null;
}
@Override
protected void onStop() {
super.onStop();
try {
// make sure you close the socket upon exiting
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
logcat errors;
01-22 18:37:40.100: E/ClientActivity(19568): C: Error
01-22 18:37:40.100: E/ClientActivity(19568): java.net.ConnectException: failed to connect to /10.0.2.15 (port 8080): connect failed: EHOSTUNREACH (No route to host)
01-22 18:37:40.100: E/ClientActivity(19568): at libcore.io.IoBridge.connect(IoBridge.java:114)
01-22 18:37:40.100: E/ClientActivity(19568): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
01-22 18:37:40.100: E/ClientActivity(19568): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
01-22 18:37:40.100: E/ClientActivity(19568): at java.net.Socket.startupSocket(Socket.java:566)
01-22 18:37:40.100: E/ClientActivity(19568): at java.net.Socket.<init>(Socket.java:225)
01-22 18:37:40.100: E/ClientActivity(19568): at com.example.client.ClientActivity$ClientThread.run(ClientActivity.java:60)
01-22 18:37:40.100: E/ClientActivity(19568): at java.lang.Thread.run(Thread.java:856)
01-22 18:37:40.100: E/ClientActivity(19568): Caused by: libcore.io.ErrnoException: connect failed: EHOSTUNREACH (No route to host)
01-22 18:37:40.100: E/ClientActivity(19568): at libcore.io.Posix.connect(Native Method)
01-22 18:37:40.100: E/ClientActivity(19568): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85)
01-22 18:37:40.100: E/ClientActivity(19568): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
01-22 18:37:40.100: E/ClientActivity(19568): at libcore.io.IoBridge.connect(IoBridge.java:112)
1.connect two device with a network (WIFI)
2.you can get ip address of each device via programmatically in android
3.and make a textview which shows the two ip address
4.type it in both connect it