Develop Reference

TCP socket in Android

My problem is I have implemented a TCP socket client in android which sends continuously "Hello" messages to the server to maintain a client-server connection and receives messages from the server.
In Android, I have initialized a boolean variable that is controlling the thread if my app is in the background I make the "AppConfig.finished" variable true inactivity on pause and on stop method to stop the socket thread and make it false when in on resume state.
But my app is consuming high CPU usage which is making my app slow, I have checked it in android's profiler. Please help me to optimize it.
The code is given below.
public class MyTcp extends Thread{
private BufferedInputStream inputStream;
private BufferedOutputStream outputStream;
private Socket MySock;
private static SocketStatus SS;
private int ConnectAttemptCount = 0;
private CheckConnectionStatus CheckStatus = null;
public boolean FirstAttempt = true;
public boolean Continue = true;
private boolean isDirectChecked = false;
String tempData = "";
private final ArrayBlockingQueue<String> Queue = new ArrayBlockingQueue<>(100);
public MyTcp(SocketStatus SS) {
MyTcp.SS = SS;
MyTcp.SS.isConnected = false;
setDaemon(true);
Thread t = new Thread(new DequeueMessageThread());
t.setName(SS.SocketName + " DequeqeMessageThread");
t.start();
setName(SS.SocketName);
}
public void Dispose() {
try {
Continue = false;
SS.isConnected = false;
if(inputStream != null) {
inputStream.close();
}
if(outputStream !=null) {
outputStream.close();
}
if(MySock != null) {
MySock.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
public void run() {
if(!Logs.isFinished) {
try {
while (Continue) {
if (SS.isConnected) {
String fromServer = ReceiveMsg();
if (fromServer.compareTo("") != 0) {
Queue.put(fromServer);
}
ConnectAttemptCount = 0;
} else {
if (ConnectAttemptCount < SS.ConnectAttempt) {
println("run>>" + "Connection Attempt" + ConnectAttemptCount);
ConnectAttemptCount++;
Connect();
} else {
println("run>>" + "Unable To Connect to server");
break;
}
}
}
} catch (Exception e) {
println("run Exception>>" + e);
}
}
}
public void Connect() {
if(!Logs.isFinished) {
try {
if (SS.isDoQueueEmptyOnConnect) {
Queue.clear();
tempData = "";
}
if (FirstAttempt) {
FirstAttempt = false;
} else {
Utilities.println("Trying to connect with " + SS.ServerIP + " on Port " + SS.Port);
_fireStatsEvent(Status.Reconnecting, "Trying to connect with " + SS.ServerIP);
Random generator = new Random();
long wait = (long) generator.nextInt(3000) + 500;
Thread.sleep(wait);
}
MySock = (Socket) AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
try {
// Start Secure Code
return (new Socket(SS.ServerIP, SS.Port));
// End Secure Code
} catch (Exception e) {
println("Connect Exception>>" + e.toString());
}
return null;
}
});
if (MySock != null) {
SS.isConnected = true;
SocketStatus.MySock = MySock;
inputStream = new BufferedInputStream(MySock.getInputStream());
outputStream = new BufferedOutputStream(MySock.getOutputStream());
Utilities.println("Connection established with " + SS.ServerIP + " on Port " + SS.Port);
if (SocketStatus.EnablePingPong) {
if (CheckStatus != null) {
CheckStatus.Dispose();
}
SS.LastMsgTime = new Date();
CheckStatus = new CheckConnectionStatus(SS, this);
CheckStatus.setName(SS.SocketName + "Connection Status Thread");
CheckStatus.start();
}
}
} catch (Exception e) {
println("Connect>>" + e);
}
int ConnectToIPCount = 0;
if (!SS.isConnected) {
while (!SS.isConnected && ConnectToIPCount < SS.ServerIPList.size()) {
final String IP_ = SS.ServerIPList.get(ConnectToIPCount).toString();
final int Port_ = SS.Port;
println("Connect>>" + "Trying to connect with " + IP_ + " on Port " + Port_);
ConnectToIPCount++;
try {
Thread.sleep(5000);
MySock = (Socket) AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
try {
// Start Secure Code
if (!isDirectChecked) {
isDirectChecked = true;
Socket tempSock = new Socket(Proxy.NO_PROXY);
tempSock.connect(new InetSocketAddress(IP_, Port_));
return tempSock;
} else {
return (new Socket(IP_, Port_));
}
// End Secure Code
} catch (Exception e) {
println("Connect Exception>>" + e.toString());
}
return null;
}
});
if (MySock != null) {
SocketStatus.MySock = MySock;
SS.isConnected = true;
inputStream = new BufferedInputStream(MySock.getInputStream());
outputStream = new BufferedOutputStream(MySock.getOutputStream());
Utilities.println("Connection established with " + IP_ + " on port " + Port_);
if (SocketStatus.EnablePingPong) {
if (CheckStatus != null) {
CheckStatus.Dispose();
}
SS.LastMsgTime = new Date();
CheckStatus = new CheckConnectionStatus(SS, this);
CheckStatus.setName(SS.SocketName + "Connection Status Thread");
CheckStatus.start();
}
}
} catch (UnknownHostException e) {
println("Connect UnknownHostException>>" + e.toString());
} catch (IOException e) {
println("Connect IOException>>" + e.toString());
} catch (Exception e) {
println("Connect Exception>>" + e.toString());
}
}
}
}
}
public void SendMsg(String sendMsg) {
if(!Logs.isFinished) {
try {
println("SendMsg>>" + sendMsg);
if (MySock != null && MySock.isConnected()) {
try {
byte[] b = null;
b = sendMsg.getBytes();
outputStream.write(b, 0, b.length);
outputStream.flush();
} catch (SocketException | SocketTimeoutException e) {
if (MySock != null) {
MySock.close();
}
SS.isConnected = false;
} catch (Exception e) {
println("SendMsg Exception>>" + e.toString());
}
}
} catch (Exception e) {
Log.d("TCP Client SendMsg >>", "Unable To Connect to server");
}
}
}
public String ReceiveMsg() {
String recvMsg = "";
if(!Logs.isFinished) {
try {
byte[] b = new byte[8092 * 6];
int recvsz = 0;
if (MySock != null && MySock.isConnected()) {
recvsz = inputStream.read(b, 0, b.length);
if (recvsz > 0) {
try {
byte[] b2 = new byte[recvsz];
System.arraycopy(b, 0, b2, 0, b2.length);
recvMsg = (new String(b2));
if (recvMsg.length() > 0) {
SS.LastMsgTime = new Date();
}
} catch (Exception e) {
println("ReceiveMsg Exception>>" + e.toString());
}
}
}
} catch (Exception e) {
if (SS.isConnected) {
Utilities.handleException(e);
}
SS.isConnected = false;
println("ReceiveMsg Exception>>>" + e.toString());
Log.d("RESPONSE FROM SERVER", "S: Received Message: '" + e.toString() + "'");
}
}
return recvMsg;
}
public void println(String msg) {
if (SS.Debug) {
String strDateFormat1 = "HH:mm:ss";
SimpleDateFormat sdf1 = new SimpleDateFormat(strDateFormat1);
Utilities.println(SS.SocketName + " (" + sdf1.format(new Date()) + ") " + msg);
}
}
private final List<MessageRecieveListner> _listeners = new ArrayList<>();
private final List<MessageRecieveListner> _listenersStrength = new ArrayList<>();
public synchronized void addListener(MessageRecieveListner l) {
_listeners.add(l);
_listenersStrength.add(l);
}
private synchronized void _fireMessageEvent(String msg) {
MessageRecieveEvent MsgEvent = new MessageRecieveEvent(this, msg);
for (MessageRecieveListner listener : _listeners) {
listener.MessageRecieved(MsgEvent);
}
}
public synchronized void _fireStatsEvent(Status status, String msg) {
MessageRecieveEvent MsgEvent = new MessageRecieveEvent(this, status, msg);
for (MessageRecieveListner listener : _listeners) {
listener.ConnectionStatus(MsgEvent);
}
}
private class DequeueMessageThread implements Runnable {
public DequeueMessageThread() {
}
#Override
public void run() {
if(!Logs.isFinished) {
while (Continue) {
if (!Queue.isEmpty()) {
try {
String data = Queue.take().trim();
if (SS.MessageParser.length() > 0) {
if (data.lastIndexOf(SS.MessageParser) == data.length() - 1) {
_fireMessageEvent(tempData + data);
tempData = "";
} else {
if (data.indexOf(SS.MessageParser) > 0) {
String particalCompleteData = tempData + data.substring(0, data.lastIndexOf(SS.MessageParser));
tempData = data.substring(data.lastIndexOf(SS.MessageParser) + 1);
_fireMessageEvent(particalCompleteData);
Utilities.println("incomplete data");
}
}
} else {
_fireMessageEvent(data);
}
} catch (Exception ex) {
ex.printStackTrace();
Continue = false;
}
}
}
}
}
}

How to transmit of stream of data to multiple devices using sockets in Android?

I am trying to transmit a continuous stream of data to multiple devices over a portable hotspot connection using sockets.
I am facing two problems:
The message only gets displayed to the client AFTER all the messages are displayed in msg TextView on the server end. So if I use an infinite while(true) loop instead of for(int i = 0; i < 1000; i++), in ServerSocketReplyThread, the message never gets transmitted, and the client eventually crashes
I am unable to connect another client to the server until all the messages have been transmitted to the first client.
How do I structure the code to ensure simultaneous, real-time transmission to multiple clients?
Here's what the code looks like:
I am using an activity called Transmit activity, where I am instantiating the msg Textview, which replays the sent messages, and a server object.
msg = (TextView) findViewById(R.id.server_replayed_messages);
Server server = new Server(this);
The Server class is as follows:
public class Server {
TransmitActivity activity;
ServerSocket serverSocket;
String message = "";
static final int socketServerPORT = 8080;
ArrayList<Socket> socketList = new ArrayList<Socket>();
public Server(TransmitActivity a) {
this.activity = a;
Thread socketServerThread = new Thread(new SocketServerThread());
socketServerThread.start();
}
public int getPort() {
return socketServerPORT;
}
public void onDestroy() {
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class SocketServerThread extends Thread {
int count = 0;
#Override
public void run() {
try {
// create ServerSocket using specified port
serverSocket = new ServerSocket(socketServerPORT);
while (true) {
// block the call until connection is created and return
// Socket object
Socket socket = serverSocket.accept();
count++;
message += "#" + count + " from "
+ socket.getInetAddress() + ":"
+ socket.getPort() + "\n";
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
activity.msg.setText(message);
}
});
SocketServerReplyThread socketServerReplyThread =
new SocketServerReplyThread(socket, count);
socketServerReplyThread.run();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class SocketServerReplyThread extends Thread {
private Socket hostThreadSocket;
int cnt;
SocketServerReplyThread(Socket socket, int c) {
hostThreadSocket = socket;
cnt = c;
}
#Override
public void run() {
OutputStream outputStream;
for(int i = 0; i < 1000; i++) {
String msgReply = DateFormat.getDateTimeInstance().format(new Date());
try {
outputStream = hostThreadSocket.getOutputStream();
PrintStream printStream = new PrintStream(outputStream);
printStream.print(msgReply);
printStream.flush();
message += "replayed: " + msgReply + "\n";
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
activity.msg.setText(message);
}
});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
message += "Something wrong in SocketServerReplyThread! " + e.toString() + "\n";
}
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
activity.msg.setText(message);
}
});
}
}
}
}
On the client side I have a ReceiveActivity, where I am using the following code when a "Connect" button is clicked:
Client myClient = new Client(editTextAddress.getText()
.toString(), Integer.parseInt(editTextPort
.getText().toString()), response);
myClient.execute();
The Client class is as follows:
public class Client extends AsyncTask<Void, Void, Void> {
String dstAddress;
int dstPort;
String response = "";
TextView textResponse;
Client(String addr, int port, TextView textResponse) {
dstAddress = addr;
dstPort = port;
this.textResponse = textResponse;
}
#Override
protected Void doInBackground(Void... arg0) {
Socket socket = null;
try {
socket = new Socket(dstAddress, dstPort);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(1024);
byte[] buffer = new byte[1024];
int bytesRead;
InputStream inputStream = socket.getInputStream();
/*
* notice: inputStream.read() will block if no data return
*/
while ((bytesRead = inputStream.read(buffer)) != -1) {
byteArrayOutputStream.write(buffer, 0, bytesRead);
response += byteArrayOutputStream.toString("UTF-8");
}
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "UnknownHostException: " + e.toString();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "IOException: " + e.toString();
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return null;
}
#Override
protected void onPostExecute(Void result) {
textResponse.setText(response);
super.onPostExecute(result);
}
}
Any help would be much appreciated.

An error upon audio recording on Android

My application starts a thread A to save some data. In this thread I call the function startRecording(audioFile.getAbsolutePath());
But I get the following error:
start called in an invalid state: 16; at android.media.MediaRecorder.start(Native Method)
This error does not occur everytime, but sometimes I get this error report from my application.
Below, there's my code.
public void startRecording(String outputPath) {
if (recorder == null) {
recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
recorder.setAudioSamplingRate(RECORDER_SAMPLERATE_22050);
recorder.setOutputFile(outputPath);
try {
recorder.prepare();
} catch (IOException e) {
e.printStackTrace();
}
}
recorder.start();
SampleRecordThread thread = new SampleRecordThread(outputPath);
thread.start();
}
private class SampleRecordThread extends Thread {
private volatile boolean running = true;
public void exit() {
running = false;
}
#Override
public void run() {
while (running) {
try {
Thread.sleep(10 * 1000);//to record 10 seconds sound
} catch (InterruptedException e) {
e.printStackTrace();
}
recorder.stop();
recorder.reset();
recorder.release();
recorder = null;
// upload the data to cloud
if (isWifiActive && isInstallationSaved) {
.....
record.saveInBackground();
}
break;
}
}

I think you try recording while previous recorder not stopped and released
You can use my class
public class AudioRecordManager {
public interface OnAudioRecordCallback {
void onComplete(String path);
void onFailed(int code);
}
private OnAudioRecordCallback onAudioRecordCallback;
public void setOnAudioRecordCallback(OnAudioRecordCallback onAudioRecordCallback) {
this.onAudioRecordCallback = onAudioRecordCallback;
}
private MediaRecorder myRecorder;
private String outputFile;
private AudioRecordThread audioRecordThread;
public AudioRecordManager() {
audioRecordThread = new AudioRecordThread();
}
private AudioRecordThread audioRecordThread;
public void startRecord() {
if(audioRecordThread == null || !audioRecordThread.isRunning()){
new Thread(audioRecordThread).start();
}
}
public void stopRecord() {
if(audioRecordThread!=null && audioRecordThread.isRunning()) {
audioRecordThread.stopRecording();
}
}
class AudioRecordThread implements Runnable {
private boolean isRunning;
private boolean isStop;
private long startTime;
private void startRecord() {
isRunning = true;
isStop = false;
File folder = new File(Content.AUDIO_DIR);
if (!folder.exists()) {
boolean b = folder.mkdirs();
}
startTime = System.currentTimeMillis();
outputFile = folder.getPath() + "/rec_" + startTime + ".mp3";
myRecorder = new MediaRecorder();
myRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
myRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
myRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
myRecorder.setOutputFile(outputFile);
try {
myRecorder.prepare();
myRecorder.start();
startTime = System.currentTimeMillis();
} catch (Exception e) {
e.printStackTrace();
}
}
private void stopRecord() {
final long stopTime = System.currentTimeMillis();
try {
if(System.currentTimeMillis() - startTime < 500){
try{
Thread.sleep(500);
}catch (Exception e){
e.printStackTrace();
}
}
myRecorder.stop();
myRecorder.release();
myRecorder = null;
} catch (Exception e) {
myRecorder = null;
e.printStackTrace();
}
if (stopTime - startTime > 1000) {
if (onAudioRecordCallback != null) {
onAudioRecordCallback.onComplete(outputFile);
}
} else {
File current = new File(outputFile);
current.delete();
if (onAudioRecordCallback != null) {
onAudioRecordCallback.onFailed(2);
}
}
isRunning = false;
}
#Override
public void run() {
startRecord();
while (!isStop) {
try {
Thread.sleep(30);
} catch (Exception e) {
e.printStackTrace();
}
}
stopRecord();
}
public void stopRecording() {
isStop = true;
}
public boolean isRunning() {
return isRunning;
}
}
}

Android UI from other thread

I'm creating an application that gets the get the homestatus from a server in json but this happens on another thread. this isn't a problem when i try to set most Items on the ui because i can set them in a static void. but when i try to create a new switch and space i can't call 'this' to create a new.
code for getting the homestatus:
public void loadHomeStatus()
{
if(socket != null) {`enter code here`
if (socket.isConnected()) {
Log.d("BtnUpdate","already connected");
return;
}
}
swAlarm = (Switch) findViewById(R.id.swAlarmState);
tvTemperature = (TextView) findViewById(R.id.tvTemprateur);
tvHumidity = (TextView) findViewById(R.id.tvHumidity);
llDevices = (LinearLayout) findViewById(R.id.llDevices);
new Thread() {
public void run() {
try
{
busyConnecting = true;
Log.d("loadHomeStatus","trying to connect to: " + host + ":" + port);
socket = new Socket(host, port);
uiConnected();
Log.d("loadHomeStatus","Connected");
DataOutputStream os = new DataOutputStream(socket.getOutputStream());
DataInputStream is = new DataInputStream(socket.getInputStream());
os.writeBytes(password);
Log.d("Connect", "send: " + password);
while (socket.isConnected()) {
byte[] data = new byte[500];
int count = is.read(data);
String recieved = new String(data).trim();
Log.d("loadHomeStatus","recieved " + recieved );
if(recieved.toLowerCase() == "failed")
{
Log.d("loadHomeStatus","failed to log in");
}
else
{
try
{
homeStatus = new Gson().fromJson(recieved, HomeStatus.class);
uiLoadStatus();
} catch (Exception e)
{
Log.d("Error", e.toString());
}
}
}//end of while loop
Log.w("loadHomeStatus", "end connection thread ");
//ends thread
Thread.currentThread().interrupt();
return;
}
catch (UnknownHostException e)
{
e.printStackTrace();
Log.w("loadHomeStatus", "no Failed to connect: " + host + "-" + 8001);
}
catch (IOException e)
{
e.printStackTrace();
Log.w("loadHomeStatus", "no Failed to connect: " + host + "-" + 8001);
}
Log.w("loadHomeStatus","Connection ended");
socket = null;
busyConnecting = false;
uiDisconnected();
}
}.start();
}`
Code for setting ui
public static void uiLoadStatus()
{
if (homeStatus != null)
{
try {
tvTemperature.post(new Runnable()
{
public void run()
{
//Log.d("uiLoadStatus to string",homeStatus.toString());
tvTemperature.setText(homeStatus.temperature + "°C");
tvHumidity.setText(homeStatus.humidity + "%");
}
});
}
catch(Exception e)
{
Log.d("uiLoadStatus status fragment", e.toString());
}
try {
swAlarm.post(new Runnable()
{
public void run() {
swAlarm.setChecked(homeStatus.alarmState);
}
});
}
catch (Exception e)
{
Log.d("uiLoadStatus alarm fragment", e.toString());
}
}
try {
llDevices.post(new Runnable()
{
public void run() {
uiLoadDevices(); //this gives and error because it's not static
}
});
}
catch (Exception e)
{
Log.d("uiLoadStatus alarm fragment", e.toString());
}
}
public void uiLoadDevices()
{
for (int i = 0; i < homeStatus.lstDevices.size(); i++) {
String deviceAdd = homeStatus.lstDevices.get(i);
Space mySpace = new Space(this);
Switch mySwitch = new Switch(this);
mySpace.setMinimumHeight(50);
mySwitch.setText(homeStatus.getName(deviceAdd));
mySwitch.setChecked(homeStatus.getState(deviceAdd));
mySwitch.setTextSize(18);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
lp.gravity = Gravity.LEFT;
llDevices.addView(mySpace, lp);
llDevices.addView(mySwitch, lp);
}
}

You should use AsyncTask and put the network interaction part in the doInBackground() method. To update the UI components, implement those logics in the onPostExecute() method

uiLoadStatus is a static method (not sure why or if it has to be without looking at all of your code) and therefore you cannot call non-static methods from within it, such as uiLoadDevices
I would advise taking a look at your code and update your uiLoadStatus to not be static if at all possible. Abusing static can lead to sloppy code.

TCP in Android - ObjectOutputStream writeObject failure

I'm trying to send an Object from my phone to my PC(Windows) using a TCP socket via WiFi. When I try the same code between two PCs, it works without any error. But when I put the client code to the android device, it fails to send date using writeObject method. But writeUTF command works. It gives the "Software caused connection abort: recv failed" error. Below is the Code. Please help..
Server(in PC):
public class Test {
public static void main(String arg[]) {
ServerSocket serverSocket = null;
Socket socket = null;
ObjectInputStream in = null;
ObjectOutputStream out = null;
try {
serverSocket = new ServerSocket(8888);
System.out.println("Listening :8888");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
while (true) {
try {
socket = serverSocket.accept();
in = new ObjectInputStream(socket.getInputStream());
out = new ObjectOutputStream(socket.getOutputStream());
out.flush();
System.out.println("ip: " + socket.getInetAddress());
Message msg = (Message) in.readObject(); //Message captured from chat client.
System.out.println(msg.type + " message received from " + msg.sender + " Containing " + msg.content);
out.writeObject(new Message("Ack", "Server", "Message Received", "Client"));
out.flush();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException ex) {
Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
}
finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
}
Client (in Android Device):
public class MainActivity extends Activity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button bb=(Button)findViewById(R.id.button1);
bb.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
new Send().execute();
}
});
}
#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;
}
private class Send extends AsyncTask<Void, Void, Void> {
Socket socket = null;
ObjectOutputStream out = null;
ObjectInputStream in = null;
protected Void doInBackground(Void... arg0) {
try {
socket = new Socket("192.168.43.92", 8888); //use the IP address of the server
out = new ObjectOutputStream(socket.getOutputStream());
out.flush();
out.writeObject(new Message("Chat", "Server", "Hello World", "Server")); //This method is used to write something to the server.
out.flush();
Message msg = (Message) in.readObject();
System.out.println(msg.type + " message received from " + msg.sender + " Containing " + msg.content);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return null;
}
protected void onProgressUpdate(Integer... progress) {
//setProgressPercent(progress[0]);
}
protected void onPostExecute(Long result) {
//showDialog("Downloaded " + result + " bytes");
}
}
}
Message(in Both Sides):
public class Message implements Serializable{
private static final long serialVersionUID = 1L;
public String type, sender, content, recipient;
public Message(String type, String sender, String content, String recipient){
this.type = type; this.sender = sender; this.content = content; this.recipient = recipient;
}
#Override
public String toString(){
return "{type='"+type+"', sender='"+sender+"', content='"+content+"', recipient='"+recipient+"'}";
}
}

Is the network between the client and server setup properly via your WiFi? Download one of those ping & telnet test apps and use it to test your network connection.
Telnet is a useful TCP debugging app. If you have a server listening on 11.22.33.44 port 1234, you should be able to telnet 11.22.33.44 1234

Maybe, you need to add this functions into Message class:
private void writeObject(java.io.ObjectOutputStream stream)
throws IOException {
stream.writeObject(type);
stream.writeObject(sender);
stream.writeObject(content);
stream.writeObject(recipient);
}
private void readObject(java.io.ObjectInputStream stream)
throws IOException, ClassNotFoundException {
type = (String) stream.readObject();
sender = (String) stream.readObject();
content = (String) stream.readObject();
recipient = (String) stream.readObject();
}
http://developer.android.com/reference/java/io/Serializable.html