Develop Reference

How getOutputStream() of Socket from another class?

I have two classes:
MainActivity.class
ScreenCapture.class
and want getOutputStream(); from a Socket that is located on MainActivity.class.
Then i do:
MainActivity.INSTANCE.clientSocket.getOutputStream();
but is failing in this line ^, i not left logcat here because my logcat not is catching all events correctly, but from this description hope that someone can help.
MainActivity
public class MainActivity extends AppCompatActivity {
public static final MainActivity INSTANCE = new MainActivity();
public Socket clientSocket;
private final int SERVERPORT = 101;
private final String SERVER_IP = "192.168.15.13";
/////////////////////////////////////////////// CLIENTSOCKET //////////////////////////////////////////////////////
class ClientThread implements Runnable {
#Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
clientSocket = new Socket(serverAddr, SERVERPORT);
new Thread(new CommsThread()).start();
} catch (Exception e1) {
System.out.println(e1.toString());
}
}
}
class CommsThread implements Runnable {
#Override
public void run() {
try {
System.out.println("Waiting for server request");
while(clientSocket.isConnected()){
BufferedReader reader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream())),true);
if (reader.ready()) {
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line);
if(line != null && !line.trim().isEmpty()) {
if(line.equalsIgnoreCase("screen")){
// Do something
out.flush();
}
if(line.equalsIgnoreCase("exit")) break;
}
}
}
Thread.sleep(100);
}
System.out.println("Shutting down Socket!!");
clientSocket.close();
} catch (Exception e1) {
System.out.println(e1.toString());
}
}
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread(new ClientThread()).start();
}
ScreenCapture
public class ScreenCaptureClass {
#UiThread
public boolean takeScreenshot(#NonNull Context context) {
//...
imageReader.setOnImageAvailableListener(new OnImageAvailableListener() {
#Override
public void onImageAvailable(final ImageReader reader) {
new AsyncTask<Void, Void, Bitmap>() {
#Override
protected Bitmap doInBackground(final Void... params) {
// ...
OutputStream outs = MainActivity.INSTANCE.clientSocket.getOutputStream(); // <= Error is here
}
}
}
}
}
}

Try to pass the socket's reference to your ScreenCaptureClass, you can try the following things:
You can pass your socket through the ScreenCaptureClass constructor (probably the best way).
Inside your ScreenCaptureClass you can add a static variable like private static OutputStream outputStream and a setter called from your MainActivity :
public static void setOutputStream(OutputStream os) {
outputStream = os;
}

Simple Android Socket Programming

I am learning android socket programming. The code is given below. At the first click of the button, message is being sent to the server successfully but after the second click message is not going to the server and also it is not showing any error.
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private InetAddress address;
private Button send;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
send = (Button) this.findViewById(R.id.Send);
send.setOnClickListener(this);
}
#Override
public void onClick(View v) {
new Sender().execute("xxx.xxx.xx.xxx");
}
private class Sender extends AsyncTask<String, Void, Void> {
private Socket socket;
private Connector connector;
public Sender() {}
#Override
protected Void doInBackground(String... params) {
try {
address = InetAddress.getByName(params[0]);
socket = new Socket(address, 10001);
connector = new Connector(socket);
connector.write("Hello server, this is client");
} catch (UnknownHostException e) {
Log.d("Error", e.getLocalizedMessage());
} catch (IOException e) {
Log.d("Error", e.getLocalizedMessage());
}
return null;
}
}
}
public class Connector {
private Socket socket;
private PrintWriter writer;
public Connector(Socket soc) {
socket = soc;
try {
writer = new PrintWriter(socket.getOutputStream(), true);
} catch (IOException e) {
Log.d("Error", e.getLocalizedMessage());
}
}
public void write(String message) {
writer.println(message);
}
}

how to repeate sending value by socket

I have this client and server communication program. I got the idea from Android-er website.
This codes send a one random number when the customer pressing the connection button and I want to send new random number of every five minutes when the client had been connected with server.
Client code:
public class MainActivity extends AppCompatActivity {
TextView textResponse;
EditText editTextAddress, editTextPort;
Button buttonConnect, buttonClear;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editTextAddress = (EditText)findViewById(R.id.address);
editTextPort = (EditText)findViewById(R.id.port);
buttonConnect = (Button)findViewById(R.id.connect);
buttonClear = (Button)findViewById(R.id.clear);
textResponse = (TextView)findViewById(R.id.response);
buttonConnect.setOnClickListener(buttonConnectOnClickListener);
buttonClear.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
textResponse.setText("");
}});
}
View.OnClickListener buttonConnectOnClickListener = new View.OnClickListener(){
#Override
public void onClick(View arg0) {
MyClientTask myClientTask = new MyClientTask(
editTextAddress.getText().toString(),
Integer.parseInt(editTextPort.getText().toString()));
myClientTask.execute();
}};
public class MyClientTask extends AsyncTask<Void, Void, Void> {
String dstAddress;
int dstPort;
String response = "";
MyClientTask(String addr, int port){
dstAddress = addr;
dstPort = port;
}
#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);
}
}
}
and this is the code of server:
public class MainActivity extends AppCompatActivity {
TextView info, infoip, msg, randGen;
String message = "";
ServerSocket serverSocket;
String vRand="";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
info = (TextView) findViewById(R.id.info);
infoip = (TextView) findViewById(R.id.infoip);
msg = (TextView) findViewById(R.id.msg);
randGen= (TextView)findViewById(R.id.viewRand);
infoip.setText(getIpAddress());
Thread socketServerThread = new Thread(new SocketServerThread());
socketServerThread.start();
}
public String rGenerate() {
Random rand= new Random();
int number= rand.nextInt(500-251)+251;
vRand = String.valueOf(number);
//randGen.setText(vRand);
return vRand;
}
#Override
protected void onDestroy() {
super.onDestroy();
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class SocketServerThread extends Thread {
static final int SocketServerPORT = 8080;
int count = 0;
#Override
public void run() {
try {
serverSocket = new ServerSocket(SocketServerPORT);
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
info.setText("I'm waiting here: "
+ serverSocket.getLocalPort());
}
});
while (true) {
Socket socket = serverSocket.accept();
count++;
message += "#" + count + " from " + socket.getInetAddress()
+ ":" + socket.getPort() + "\n";
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
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;
String num =rGenerate();
try {
outputStream = hostThreadSocket.getOutputStream();
PrintStream printStream = new PrintStream(outputStream);
printStream.print(num);
printStream.close();
message += num + "\n";
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
message += "Something wrong! " + e.toString() + "\n";
}
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
}
}
private String getIpAddress() {
String ip = "";
try {
Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface
.getNetworkInterfaces();
while (enumNetworkInterfaces.hasMoreElements()) {
NetworkInterface networkInterface = enumNetworkInterfaces
.nextElement();
Enumeration<InetAddress> enumInetAddress = networkInterface
.getInetAddresses();
while (enumInetAddress.hasMoreElements()) {
InetAddress inetAddress = enumInetAddress.nextElement();
if (inetAddress.isSiteLocalAddress()) {
ip += "SiteLocalAddress: "
+ inetAddress.getHostAddress() + "\n";
}
}
}
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
ip += "Something Wrong! " + e.toString() + "\n";
}
return ip;
}
}

You can use handler to perform tasks at specific delay. I assumed you know how to send the random numbers using sockets so i wont mess socket codes
Button button = (Button) findViewById(R.id.start_button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
handler.postDelayed(new Runnable() {
#Override
public void run() {
sendData();
handler.postDelayed(this, 15000);
}
}, 15000);
}
});
private void sendData(){
new Worker().execute();
}
private class Worker extends AsyncTask<Void, Void, String>{
private static final String TAG = "Worker";
#Override
protected String doInBackground(Void... params) {
return "Hello There";
}
#Override
protected void onPostExecute(String s) {
Log.i(TAG, s);
}
}

You can use a Handler to do something in a certain time period. Try this
Handler customHandler = new android.os.Handler();
static final int SOCKET_VERIFY_TIME = 5000; //milliseconds
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
customHandler.postDelayed(updateTimerThread, SOCKET_VERIFY_TIME);
...
}
private Runnable updateTimerThread = new Runnable() {
public void run()
{
if(socket != null) {
if(socket.connected()) {
socket.emit("eventNumber", randNumber);
}
}
customHandler.postDelayed(this, SOCKET_VERIFY_TIME);
}
};
if you want stop updates use this
customHandler.removeCallbacks(updateTimerThread);
In your Client
public class MainActivity extends AppCompatActivity {
TextView textResponse;
EditText editTextAddress, editTextPort;
Button buttonConnect, buttonClear;
Handler customHandler = new android.os.Handler();
static final int SOCKET_VERIFY_TIME = 5000; //milliseconds
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editTextAddress = (EditText)findViewById(R.id.address);
editTextPort = (EditText)findViewById(R.id.port);
buttonConnect = (Button)findViewById(R.id.connect);
buttonClear = (Button)findViewById(R.id.clear);
textResponse = (TextView)findViewById(R.id.response);
buttonConnect.setOnClickListener(buttonConnectOnClickListener);
buttonClear.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
textResponse.setText("");
}});
/***** Events Socket ***********/
socket = IO.socket(new URI(URL_SERVER));
socket.on(Socket.EVENT_CONNECT, new Emitter.Listener() {
#Override
public void call(Object... args) {
yourActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
// Socket is connect. Do something here
/******************* Set Handler delay ******************/
customHandler.postDelayed(updateTimerThread, SOCKET_VERIFY_TIME);
/************************************************/
}
});
}
}).on(Socket.EVENT_DISCONNECT, new Emitter.Listener() {
#Override
public void call(final Object... args) {
runOnUiThread(new Runnable() {
#Override
public void run() {
// Socket is disconnect. Do something here
customHandler.removeCallbacks(updateTimerThread); // stop handler updates
}
});
}
})
}
View.OnClickListener buttonConnectOnClickListener = new View.OnClickListener(){
#Override
public void onClick(View arg0) {
MyClientTask myClientTask = new MyClientTask(
editTextAddress.getText().toString(),
Integer.parseInt(editTextPort.getText().toString()));
myClientTask.execute();
}};
private Runnable updateTimerThread = new Runnable() {
public void run()
{
if(socket != null) {
if(socket.connected()) {
socket.emit("eventNumber", randNumber);
}
}
customHandler.postDelayed(this, SOCKET_VERIFY_TIME);
}
};
public class MyClientTask extends AsyncTask<Void, Void, Void> {
String dstAddress;
int dstPort;
String response = "";
MyClientTask(String addr, int port){
dstAddress = addr;
dstPort = port;
}
#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);
}
}
}

Android send received data from a socket service to Activity

I am looking for a way to send received data (receive while flag is set) from a socket service to an activity that is bound to the service. What is the best way to do this ? Handlers , AsyncTask or something else ?
this is the SocketClass I am using to start a connection and handle the incoming messages :
class connectSocket implements Runnable {
#Override
public void run() {
running= true;
try {
socket = new Socket(serverAddr, SERVERPORT);
try {
mBufferOut = new ObjectOutputStream(socket.getOutputStream());
mBufferIn = new ObjectInputStream(socket.getInputStream());
while(running){
msg = (Message) mBufferIn.readObject();
}
}
catch (Exception e) {
Log.e("TCP", "S: Error", e);
}
} catch (Exception e) {
Log.e("TCP", "C: Error", e);
}
}
}
Update :
public class SocketService extends Service {
private static final String TAG = "com.oos.kiesa.chat";
public static final String SERVERIP = "192.168.X.X";
public static final int SERVERPORT = 4444;
private ObjectOutputStream mBufferOut;
private ObjectInputStream mBufferIn;
Socket socket;
InetAddress serverAddr;
boolean mRun;
Object msg;
public Integer command;
#Override
public IBinder onBind(Intent intent) {
return myBinder;
}
private final IBinder myBinder = new LocalBinder();
public class LocalBinder extends Binder {
public SocketService getService() {
return SocketService.this;
}
}
#Override
public void onCreate() {
super.onCreate();
}
public void IsBoundable(){
Toast.makeText(this,"is boundable", Toast.LENGTH_LONG).show();
}
public void sendMessage(String message) throws IOException {
if (mBufferOut != null) {
mBufferOut.writeObject(message);
mBufferOut.flush();
}
}
public void sendMessage(Message message) throws IOException {
if (mBufferOut != null) {
mBufferOut.writeObject(message);
mBufferOut.flush();
}
}
public void sendMessage(User user) throws IOException {
if (mBufferOut != null) {
mBufferOut.writeObject(user);
mBufferOut.flush();
}
}
public void sendMessage(int command) throws IOException {
if (mBufferOut != null) {
mBufferOut.writeInt(command);
mBufferOut.flush();
}
}
#Override
public int onStartCommand(Intent intent,int flags, int startId){
super.onStartCommand(intent, flags, startId);
System.out.println("I am in on start");
Runnable connect = new connectSocket();
new Thread(connect).start();
return START_STICKY;
}
public void stopClient() throws IOException{
if (mBufferOut != null) {
mBufferOut.flush();
mBufferOut.close();
}
mBufferIn = null;
mBufferOut = null;
socket.close();
}
class connectSocket implements Runnable {
#Override
public void run() {
mRun = true;
try {
socket = new Socket(serverAddr, SERVERPORT);
try {
mBufferOut = new ObjectOutputStream(socket.getOutputStream());
mBufferIn = new ObjectInputStream(socket.getInputStream());
while(mRun){
switch(command.intValue()){
case Constants.ADD_MESSAGE:
msg = (Message) mBufferIn.readObject(); // send message to Activity
break;
}
}
}
catch (Exception e) {
Log.e("TCP", "S: Error", e);
}
} catch (Exception e) {
Log.e("TCP", "C: Error", e);
}
}
}
#Override
public void onDestroy() {
super.onDestroy();
try {
socket.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
socket = null;
}
}
Some guidance / examples would be greatly appreciated

I am sending you mine, hope it will help :
class SocketRequestHandler extends Thread {
static String EOF = "<EOF>";
TCPResponseModel tcpResponseDS;
Activity activity;
boolean doSkip = false;
String responseStringComplete = "";
Socket clientSocekt;
OutputStream clientSocketOutputStream;
PrintWriter clinetSocketPrintWriter;
DataInputStream clientSocketInputStream;
private SocketRequestHandler(TCPResponseModel tcpResponseDS, Activity activity, SaloonListener listener) {
this.tcpResponseDS = tcpResponseDS;
this.activity = activity;
this.listener = listener;
moreStores = tcpResponseDS.StoresFound;
}
public static SocketRequestHandler pingAll(Activity activity, TCPResponseModel tcpResponseDS, SaloonListener listener) {
SocketRequestHandler requestHandler = new SocketRequestHandler(tcpResponseDS, activity, listener);
requestHandler.start();
return requestHandler;
}
private void closeStreams() {
try {
clientSocekt.close();
clientSocketInputStream.close();
clinetSocketPrintWriter.close();
clientSocketOutputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
public void run() {
try {
String pingingHost = "URL_TO_PING";
clientSocekt = new Socket(pingingHost, 12000);
clientSocketOutputStream = clientSocekt.getOutputStream();
clinetSocketPrintWriter = new PrintWriter(clientSocketOutputStream);
String firstPing = "{\"RequestId\":" + tcpResponseDS.RequestId + "}<EOF>";
clinetSocketPrintWriter.println(firstPing);
clinetSocketPrintWriter.flush();
byte[] bytes;
String pingStr = "";
clientSocketInputStream = new DataInputStream(clientSocekt.getInputStream());
while (true) {
bytes = new byte[1024];
clientSocketInputStream.read(bytes);
bytes = trim(bytes);
if (bytes.length > 0 && !doSkip) {
String newString = new String(bytes, "UTF-8");
String decoded = pingStr + newString;
pingStr = checkForMessage(decoded);
responseStringComplete += newString;
}
if (doSkip) {
break;
}
}
closeStreams();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
System.out.print(responseStringComplete);
}
}
}
To broadcast chat data just do :
msg = (Message) mBufferIn.readObject(); // Do code after this line
Intent localIntent = new Intent("CHAT_MESSAGE");
localIntent.putExtra("message", msg);
LocalBroadcastManager.getInstance(context).sendBroadcast(localIntent);
Now in the activity where you are showing the chat list you can do
class ReceiveMessages extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals("CHAT_MESSAGE")) {
runOnUiThread(new Runnable() {
#Override
public void run() {
String chatMessage = getIntent().getStringExtra("message");
//get data from intent and update your chat list.
}
});
}
}
}
ReceiveMessages myReceiver;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//your code
myReceiver = new ReceiveMessages();
}
#Override
protected void onStart() {
super.onStart();
LocalBroadcastManager.getInstance(this).registerReceiver(myReceiver,
new IntentFilter("CHAT_MESSAGE"));
}
#Override
protected void onStop() {
super.onStop();
LocalBroadcastManager.getInstance(this).unregisterReceiver(myReceiver);
}

public class AsyncHttpClient {
public AsyncHttpClient() {
}
public static class SocketIORequest {
private String mUri;
private String mEndpoint;
private List<BasicNameValuePair> mHeaders;
public SocketIORequest(String uri) {
this(uri, null);
}
public SocketIORequest(String uri, String endpoint) {
this(uri, endpoint, null);
}
public SocketIORequest(String uri, String endpoint, List<BasicNameValuePair> headers) {
mUri = Uri.parse(uri).buildUpon().encodedPath("/socket.io/1/").build().toString();
mEndpoint = endpoint;
mHeaders = headers;
}
public String getUri() {
return mUri;
}
public String getEndpoint() {
return mEndpoint;
}
public List<BasicNameValuePair> getHeaders() {
return mHeaders;
}
}
public static interface StringCallback {
public void onCompleted(final Exception e, String result);
}
public static interface WebSocketConnectCallback {
public void onCompleted(Exception ex, WebSocketClient webSocket);
}
public void executeString(final SocketIORequest socketIORequest, final StringCallback stringCallback) {
new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
AndroidHttpClient httpClient = AndroidHttpClient.newInstance("android-websockets-2.0");
HttpPost post = new HttpPost(socketIORequest.getUri());
addHeadersToRequest(post, socketIORequest.getHeaders());
try {
HttpResponse res = httpClient.execute(post);
String responseString = readToEnd(res.getEntity().getContent());
if (stringCallback != null) {
stringCallback.onCompleted(null, responseString);
}
} catch (IOException e) {
if (stringCallback != null) {
stringCallback.onCompleted(e, null);
}
} finally {
httpClient.close();
httpClient = null;
}
return null;
}
private void addHeadersToRequest(HttpRequest request, List<BasicNameValuePair> headers) {
if (headers != null) {
Iterator<BasicNameValuePair> it = headers.iterator();
while (it.hasNext()) {
BasicNameValuePair header = it.next();
request.addHeader(header.getName(), header.getValue());
}
}
}
}.execute();
}
private byte[] readToEndAsArray(InputStream input) throws IOException {
DataInputStream dis = new DataInputStream(input);
byte[] stuff = new byte[1024];
ByteArrayOutputStream buff = new ByteArrayOutputStream();
int read = 0;
while ((read = dis.read(stuff)) != -1) {
buff.write(stuff, 0, read);
}
return buff.toByteArray();
}
private String readToEnd(InputStream input) throws IOException {
return new String(readToEndAsArray(input));
}

Trying To Create a PC to Emulator Chat Application, getting an outputstream close null pointer exception

This is the code:
private EditText userText;
private Button bsend;
private TextView chatwindow;
private Socket connection;
private ObjectOutputStream output;
private ObjectInputStream input;
private String serverIP="10.0.2.2";
private String message="";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
userText = (EditText) findViewById(R.id.userText);
userText.setEnabled(false);
chatwindow=(TextView) findViewById(R.id.chatwindow);
bsend = (Button) findViewById(R.id.bsend);
startRunning();
bsend.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
sendMessage(userText.getText().toString());
userText.setText("");
}
}
);
}
public void startRunning(){
try{
connectToServer();
setupStreams();
chatUp();
}
catch(EOFException e){
showMessage("\nServer Closed The Connection\n");
} catch (IOException e) {
e.printStackTrace();
}finally {
closeSystems();
}
}
public void connectToServer()throws IOException{
showMessage("\n********Connecting to Server......*********\n");
connection = new Socket(InetAddress.getByName(serverIP),5000);
showMessage("\n********Connection Successful*********\n");
}
public void setupStreams() throws IOException{
output = new ObjectOutputStream(connection.getOutputStream());
output.flush();
input = new ObjectInputStream(connection.getInputStream());
showMessage("\n***********Streams Setup Successfully***************\n");
}
public void chatUp() throws IOException{
ableToType(true);
showMessage("\nChatting can now Begin......\n");
do{
try {
message = (String) input.readObject();
sendMessage("\n"+message);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
while(!message.equals("SERVER - END"));
}
public void closeSystems() {
ableToType(false);
try{
output.close();
input.close();
connection.close();
}
catch(IOException e){
e.printStackTrace();
}
}
public void sendMessage(final String m){
try{
output.writeObject(m);
output.flush();
}
catch(IOException e){
e.printStackTrace();
}
}
public void showMessage(final String m){
chatwindow.append(m);
}
public void ableToType(final boolean tof){
userText.setEnabled(tof);
}
Trying to connect the emulator to the machine using the ip 10.0.2.2.
This happens only on the android system. I tested similar code on swing in eclipse and had no issue.
Appreciate it, if someone could tell me why I'm getting the Null pointer exception at output.close()
Thanks