I have made an application that opens up a socket via a thread and updates based on what is typed. Here is the code:
Server.java:
public class Server {
public static void main(String[] args) throws IOException {
int portNumber = 2392;
boolean listening = true;
System.out.println("Server: Running...");
try (ServerSocket serverSocket = new ServerSocket(portNumber)) {
System.out.println("Server: Connected to Client!");
while (listening) {
new ServerThread(serverSocket.accept()).start();
}
} catch (IOException e) {
System.out.println("Exception caught when trying to listen on port "
+ portNumber + " or listening for a connection( '" + e.getMessage() + "' );");
} finally {
System.out.println("Server: Disconnecting...");
}
}
}
Server Thread.java:
public class ServerThread extends Thread {
private Socket socket = null;
Scanner reader = new Scanner(System.in);
public ServerThread(Socket socket) {
super("ServerThread");
this.socket = socket;
}
public void run() {
System.out.println("Ruasd");
try (PrintWriter out = new PrintWriter(socket.getOutputStream(), true)) {
String outputLine = "";
while (!outputLine.equals("Disconnect")) {
outputLine = reader.nextLine();
out.println(outputLine);
}
socket.close();
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Client.java:
public class MainActivity extends Activity {
private Socket socket;
private TextView status;
private BufferedReader in;
private Handler mHandler;
private static final int SERVERPORT = 2392;
private static final String SERVER_IP = "...ip#...";
#Override
protected void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView(R.layout.activity_vitals);
status = (TextView) findViewById(R.id.text_status);
new Thread(new CommunicationThread()).start();
}
#Override
protected void onStop() {
super.onStop();
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
class CommunicationThread implements Runnable {
#Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while (true) {
final String fromServer = in.readLine();
System.out.println("Server: " + fromServer);
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
// This code will always run on the UI thread, therefore is safe to modify UI elements.
status.setText(fromServer);
}
});
if (fromServer.equals("Disconnect."))
break;
}
} catch (IOException e) {
e.printStackTrace();
}
It works perfectly the first time and outputs to the status TextView correctly. However, when I restart the application, it outputs every other word. For instance, If I type "Hey" "Hi "You" "How", I will see "Hi" and "How" in the TextView the second time I start the application.
What's really odd to me is that when I do System.out.println("Server: " + fromServer) it is outputting all values. Any suggestions are greatly appreciated.
Ok I think I found the problem (got it working for me, that is). In your CommunicationThread, you didn't have a while loop. Also, you need to iterate the server's input until it is null. See below:
class CommunicationThread implements Runnable {
#Override
public void run() {
try {
// keep the connection alive.
while (true) {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
BufferedReader in = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
String fromServer;
// get server messages until there are none
while ((fromServer = in.readLine()) != null) {
System.out.println("Server: " + fromServer);
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
// This code will always run on the UI thread, therefore is safe to modify UI elements.
status.setText(fromServer);
}
});
if (fromServer.equals("Disconnect."))
break;
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
Please get back to me on how it works out :)
Related
I am trying to connect an Android device to a java server. It works perfectly when I use the emulator but when I port it onto my phone there is no connection.
The aim of the code is to send a value from client to server, perform a calculation on it and return it back to the client to be displayed.
This is my server code:
public class ServerTest {
public static final int PORT_NUMBER = 8000;
protected Socket socket;
private ServerTest(Socket socket) {
this.socket = socket;
System.out.println("New client connected from " + socket.getInetAddress().getHostAddress());
connect();
}
public void connect() {
InputStream in = null;
OutputStream out = null;
try {
in = socket.getInputStream();
out = socket.getOutputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String request = br.readLine();
if (request.equals("end")) {
System.out.println("Message received: " + request + ". Ending connection.");
request = "End Connection";
out.write(request.getBytes());
in.close();
out.close();
socket.close();
System.exit(0);
} else {
System.out.println("Message received: " + request);
request = calculatePi(request);
System.out.println("Output: " + request);
out.write(request.getBytes());
}
} catch (IOException ex) {
System.out.println("Unable to get streams from client");
} finally {
try {
in.close();
out.close();
socket.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
public static void main(String[] args) {
System.out.println("Welcome. IP address is: " + getIP());
ServerSocket server = null;
try {
server = new ServerSocket(PORT_NUMBER);
while (true) {
new ServerTest(server.accept());
}
} catch (IOException ex) {
System.out.println("Unable to start server.");
} finally {
try {
if (server != null)
server.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
private static String getIP() {
String ip = "";
try {
Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
while (interfaces.hasMoreElements()) {
NetworkInterface iface = interfaces.nextElement();
// filters out 127.0.0.1 and inactive interfaces
if (iface.isLoopback() || !iface.isUp())
continue;
Enumeration<InetAddress> addresses = iface.getInetAddresses();
while(addresses.hasMoreElements()) {
InetAddress addr = addresses.nextElement();
// *EDIT*
if (addr instanceof Inet6Address) continue;
ip = addr.getHostAddress();
}
}
} catch (SocketException e) {
throw new RuntimeException(e);
}
return ip;
}
and this is my client side code on device:
public class MainActivity extends AppCompatActivity {
TextView piResultTextView;
EditText addressEditText, messageEditText;
Button connectButton;
Handler handler = new Handler();
Results results;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
results = new Results();
addressEditText = findViewById(R.id.AddressEditText);
messageEditText = findViewById(R.id.MessageEditText);
connectButton = findViewById(R.id.ConnectButton);
connectButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
connect();
}
});
piResultTextView = findViewById(R.id.PiResultTextView);
}
public void connect() {
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
String hostAddress = addressEditText.getText().toString();
int port = 8000;
Socket echoSocket = null;
PrintWriter out = null;
BufferedReader in = null;
try {
echoSocket = new Socket(hostAddress, port);
out = new PrintWriter(echoSocket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(echoSocket.getInputStream()));
} catch (UnknownHostException e) {
Toast.makeText(getApplicationContext(), "Unknown host: " + hostAddress, Toast.LENGTH_SHORT).show();
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Unable to get streams from server", Toast.LENGTH_SHORT).show();
}
String input = messageEditText.getText().toString();
try {
out.println(input);
results.pi = in.readLine();
handler.post(new Runnable() {
#Override
public void run() {
piResultTextView.setText(results.pi);
}
});
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Unable to read input stream from server", Toast.LENGTH_SHORT).show();
}
try {
out.close();
in.close();
echoSocket.close();
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Error closing streams", Toast.LENGTH_SHORT).show();
}
}
});
thread.start();
}
}
I am currently working on a project that requires an android app to connect to a java server that I have created. The problem is that the socket does not initialize. I have added the permissions to the AndroidManifest.xml file
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
My app code looks as follows:
Button Trigger:
View.OnClickListener btnDownloadListener = new View.OnClickListener() {
#Override
public void onClick(View v) {
//Implement download code
try{
new ConnectionManager().execute("10.90.181.91" , "21002");
}catch(Throwable t){
}
}
};
ConnectionManager Background Function:
protected String doInBackground(String... args) {
try{
Log.i("Test", "background thread started");
int port = Integer.parseInt(args[1]);
InetAddress serverAddr = InetAddress.getByName(args[0]);
Socket connSock = new Socket(serverAddr, port);
Log.i("Test", "Created Socket");
}catch(Throwable t){
}
return "";
}
The log is outputting "background Thread Started", but never outputs "Created Socket"
The Server code is as follows:
Main method
try{
ServerSocket serverSocket = null;
boolean listeningSocket = true;
try {
serverSocket = new ServerSocket(21002);
} catch (IOException e) {
System.err.println("Could not listen on port: 21002");
}
int count = 0;
while(listeningSocket){
try{
Socket clientSocket = serverSocket.accept();
new ServerThread(clientSocket).start();
}catch(Throwable t){
}
}
System.out.println("You should not be here");
serverSocket.close();
}catch(Throwable t){
}
ServerThread
public class ServerThread extends Thread {
private Socket socket = null;
private String s;
private InputStream in;
private OutputStream out;
BufferedReader is;
BufferedWriter os;
public ServerThread(Socket s) {
socket = s;
System.out.println("Thread started: " + socket.getInetAddress());
try{
in = socket.getInputStream();
out = socket.getOutputStream();
out.flush();
is = new BufferedReader(new InputStreamReader(in));
os = new BufferedWriter(new OutputStreamWriter(out));
}catch(Throwable t){
t.printStackTrace();
}
}
public void run() {
System.out.println("Thread is running");
String dataType = "";
Boolean awaitingTransfer = false;
try {
while(true){
if(in.available() > 0 && !awaitingTransfer){
dataType = is.readLine();
System.out.println(dataType);
}
if(in.available() > 0 && awaitingTransfer){
try{
ArrayList<SpotCheck> tempList = new ArrayList<SpotCheck>();
while(in.available() > 0){
//tempList = (ArrayList<SpotCheck>) in.readObject();
}
ServerMain.manager.applyChanges(tempList);
awaitingTransfer = false;
}catch(Throwable t){
t.printStackTrace();
}
}
}
} catch (Exception e) {
e.printStackTrace();
try {
in.close();
out.close();
socket.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
}
Thanks for the help!
As an amateur coder, i just wanted to ask you that, can you just add a toast to the "catch()" blog of your doInBackground like that
catch(Exception e)
{
runOnUiThread(new Runnable(){
#Override
public void run(){
Toast.makeText(getApplicationContext(), e.toString(),
Toast.LENGTH_LONG).show();
}
});
}
so it can show your problem more specifically and it will become easier to handle maybe. but again i am not sure if it works, i mean using toast in asynctask classes is a little bit more tricky.
I've tried out almost everything.
Forwarding from ADB Shell using adb forward TCP:12345 TCP:12345
Using 10.0.2.2 (without forwarding) to listen to my host machine
Setting the INTERNET permission in the manifest
Setting the thread policy to permit all functions
I'm running my client java program in 12345 port and I have a ServerSocket in the Android program that listens over the same port. But when I run my client (after running the server program on the emulator) and enter the String that I want to transfer, I get the exception saying 'Connection Refused'.
java.net.ConnectException: Connection refused: connect
Here's my server program:
public class MainActivity extends Activity {
TextView tv;
ServerSocket ss = null;
String mClientMsg = "";
Thread myCommsThread = null;
public static final int SERVERPORT = 12345;
protected static final int MSG_ID = 0x1337;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = new TextView(this);
tv.setText("Nothing from client yet");
setContentView(tv);
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);
setContentView(tv);
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();
}
}
}
}
}
}
My Java client program is as follows:
public class TCPSender {
public static void main(String args[]) {
try {
DataInputStream dis = new DataInputStream(System.in);
System.out.println("Enter the file name:");
#SuppressWarnings("deprecation")
String f = dis.readLine();
File f1 = new File(f);
FileReader fr = new FileReader(f1);
Socket s = new Socket("127.0.0.1", 12345);
PrintWriter pw = new PrintWriter(s.getOutputStream(), true);
pw.println(f);
int c = 0;
while ((c = fr.read()) != -1)
pw.println(c);
System.out.println("File content are sent....");
fr.close();
s.close();
} catch (Exception e) {
System.out.println("" + e);
}
}
}
I have got huge problem with my Android app and I would like to ask you for help.
I am currently writing Android Clietn-Server app using sockets. I have found lots of tutorils on the Internet and from them I have created basics for my project. However, all tutorials are only for one message send and that's all. I need to send more of them so I've been trying to modify it.
This are code fragments responsible for server and client. The rest is not important at this time.
Server:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
serverStatus = (TextView) findViewById(R.id.server_status);
recivedMsg = (TextView)findViewById(R.id.rec_msg);
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." + System.getProperty("line.separator"));
}
});
try {
line = null;
while (connected) {
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
if((line = in.readLine())!=null)
{
Log.d("ServerActivity", line);
handler.post(new Runnable() {
#Override
public void run() {
if(recivedMsg.equals("CLOSE"))
{
recivedMsg.append("CLOSE socket");
connected = false;
}
else
{
recivedMsg.append("MSG: " + line + System.getProperty("line.separator"));
}
// do whatever you want to the front end
// this is where you can be creative
}
});
}
else
{
recivedMsg.append("empty" + System.getProperty("line.separator"));
}
}
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();
}
}
}
Client
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
serverIp = (EditText) findViewById(R.id.server_ip);
connectPhones = (Button) findViewById(R.id.connect_phones);
sendField = (EditText) findViewById(R.id.send_field);
sendMsg = (Button) findViewById(R.id.msg_send);
connectPhones.setOnClickListener(connectListener);
sendMsg.setOnClickListener(sendMessage);
}
#Override
protected void onStop() {
super.onStop();
try {
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
//send output msg
String outMsg = "CLOSE";
out.write(outMsg);
out.flush();
// make sure you close the socket upon exiting
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private OnClickListener connectListener = new OnClickListener() {
#Override
public void onClick(View v) {
serverIpAddress = serverIp.getText().toString();
runTcpConnection();
sendMessageToServer("Msg");
}
};
private OnClickListener sendMessage = new OnClickListener() {
#Override
public void onClick(View v) {
sendMessageToServer(sendField.getText().toString());
}
};
private void runTcpConnection() {
try {
s = new Socket(serverIpAddress, SERVERPORT);
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
//send output msg
String outMsg = "TCP connecting to " + SERVERPORT + System.getProperty("line.separator");
out.write(outMsg);
out.flush();
Log.i("TcpClient", "sent: " + outMsg);
SystemClock.sleep(10);
s.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
};
public void sendMessageToServer(String str) {
try {
s = new Socket(serverIpAddress, SERVERPORT);
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
//send output msg
String outMsg = str + System.getProperty("line.separator");
out.write(outMsg);
out.flush();
Log.i("TcpClient", "sent: " + outMsg);
s.close();
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.d("", "hello222");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.d("", "hello4333");
}
}
For now devices connect correctly. Moreover They are sending the first connection messages (those in OnClickListener connectListener). The problem is that when I am trying to send another message using sendMessageToServer it is impossible. Those messages shows only after client activity is destroyed.
Very interesting is that without SystemClock.sleep(10); listener runTcpConnection() behave strange. Only 'Connected.' displays on server.
Can someone tell me what I have to do to be able to send messages normally?
EDIT:
This are things that I have found:
If I am at the connection sending more messages than all are empty (null) and after the second one connection error shows - please reconnect phones
If I am at the connection sending more messages without s.close line in sendMessageToServer only one message is passing through. No error is displayed after it.
The message form runTcpConnection shows always (except when in this function is no SystemClock.sleep(10))
Hope it will help someone to diagnose my error.
As I see, you create a new socket whenever user click button send, right? I recommend you should init it only one time when user click connect, then you use it in send click event ( because this is TCP, you will disconnect to server if you create new instance of socket)
So, you should remove these lines in sendMessageToServer :
s = new Socket(serverIpAddress, SERVERPORT);
s.close();
and this line in runTcpConnection
s.close();
Socket should close whenever you don't want communicate with the server (onstop is an example, or when change activity...)
Also you should create only one instance of BufferedWriter too.
Hope this help.
I am using a socket thread.
It takes about 5 to 10 seconds to receive a message after sending a request message.
during that time I want my main thread to show "Please wait" popup.
The process flow of the program looks something like this.
show Popup
create socket thread.
-> this will connect to server
send request message to server
receive message.
My problem is that the show popup does not show up,
until after the socket thread receives its message.
Can anybody tell me a workaround to this problem?
public class LoginActivity extends Activity {
.... <some coded>
public void onClickLogin(View view) {
Log.d(this.toString(), "onClickLogin");
showLoginLoadingPopup();
String login_id = ((EditText)findViewById(R.id.login_id)).getText().toString();
String login_pwd = ((EditText)findViewById(R.id.login_pwd)).getText().toString();
conn = new Connection(handler, 1, null);
conn.start();
conn.sendData(Connection.SSPH_USERCERT, new String[] {login_id, login_pwd});
}
}
public class Connection extends Thread implements ConnectionConstant {
private InetAddress serverAddr;
private int serverPort;
private Socket socket;
PrintWriter out;
BufferedReader in;
private Handler handler;
public Connection(Handler h, int type, ServerClass server) {
Log.d(this.toString(), "Conncetion");
setServerInfo(type, server);
handler = h;
try {
connect();
} catch (Exception e) {
Log.e(this.toString(), "Error", e);
}
}
public void run() {
Log.d(this.toString(), "run");
try {
queue();
disconnect();
} catch (Exception e) {
Log.i(this.toString(), "Information", e);
}
}
private void connect() throws Exception {
if (serverAddr != null)
Log.d(this.toString(), "connect " + serverAddr.getHostName() + "("
+ Integer.toString(serverPort) + ")");
else
Log.d(this.toString(), "connect ");
socket = new Socket(serverAddr, serverPort);
socket.setSoLinger(true, 3000);
// UTF-8
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
socket.getOutputStream())), true);
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
Log.i(this.toString(), "Socket connected!");
}
private void queue() throws Exception {
Log.d(this.toString(), "queue");
while (true) {
String sRcv = null;
sRcv = receive();
if (sRcv.length() > 0)
parseData(sRcv);
Thread.sleep(500);
Thread.yield();
}
}
private void send(String str) throws IOException {
Log.d(this.toString(), "send");
if (!socket.isConnected())
return;
Log.i(this.toString(), "Send : " + str);
out.println(str);
}
private String receive() throws Exception {
Log.d(this.toString(), "receive");
if (!socket.isConnected())
return null;
StringBuilder sb = new StringBuilder();
String str = "";
while ((str = in.readLine()) != null) {
Log.i(this.toString(), "Receive : " + str);
sb.append(str + "\n");
}
return sb.toString();
}
}
Use AsyncTask:
AsyncTask<Void, Void, Void> task = new AsyncTask<Void, Void, Void>() {
#Override
protected void onPreExecute() {
// show dialog
}
#Override
protected Void doInBackground(Void... params) {
// connect to the server
}
#Override
protected void onPostExecute(Void result) {
// close dialog
}
};
task.execute();
onPreExecute(), onPostExecute() and onProgressUpdate() are invoked on UI thread.
doInBackground() is invoked on background thread.
More about AsyncTask: http://developer.android.com/reference/android/os/AsyncTask.html
dialog = ProgressDialog.show(this, "", "Loading",true);
Runnable myRun = new Runnable(){
public void run(){
//DO ALL NETWORKING
//FINALLY DO THIS
runOnUiThread(new Runnable() {
public void run() {
}
});
};
Thread T = new Thread(myRun);
T.start();