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.
Related
I'm trying to run a UDP connection with external equipment. I want it to send a message to the equipment every 3 second and read the response.
I created 3 classes: main, sender and receive.
I open a Runnable for both sender and receive and let them sleep for 3 seconds before continue.
My problem is, when i push the button on the screen, the messages are send and received, however they are not updated on my screen because the update line is not in a loop. How do i tell it to update the screen every 3 second? the code for reading the message and show it, is this:
textViewState.setText(udpReceive.receivedMessage);
Code
public class MainActivity extends AppCompatActivity {
public static TextView textViewState;
public static Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textViewState = (TextView) findViewById(R.id.textView);
context = getApplicationContext();
}
public void buttonConnect(View v) {
(new Thread(new udpSender())).start();
(new Thread(new udpReceive())).start();
textViewState.setText(udpReceive.receivedMessage);
}
}
Class to send a message:
public class udpSender implements Runnable {
public void run() {
while (true) {
String messageStr = "Hello Android!";
int server_port = 8888;
DatagramSocket s = null;
try {
s = new DatagramSocket();
} catch (SocketException e) {
e.printStackTrace();
}
InetAddress local = null;
try {
local = InetAddress.getByName("192.168.43.159");
} catch (UnknownHostException e) {
e.printStackTrace();
}
int msg_length = messageStr.length();
byte[] message = messageStr.getBytes();
DatagramPacket p = new DatagramPacket(message, msg_length, local, server_port);
try {
s.send(p);
} catch (IOException e) {
e.printStackTrace();
}
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
Class to receive message from udp
public class udpReceive implements Runnable {
private static final int MAX_UDP_DATAGRAM_LEN = 100;
private static final int UDP_SERVER_PORT = 8888;
public static String receivedMessage;
public void run() {
while (true) {
String message;
byte[] lmessage = null;
lmessage = new byte[MAX_UDP_DATAGRAM_LEN];
DatagramPacket packet = null;
DatagramSocket socket = null;
try {
packet = new DatagramPacket(lmessage, lmessage.length);
socket = new DatagramSocket(UDP_SERVER_PORT);
socket.receive(packet);
message = new String(lmessage, 0, packet.getLength());
receivedMessage = message;
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (socket != null) {
socket.close();
}
}
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
In any class that is in another thread, try doing this
Handler handler = new Handler(getActivity().getMainLooper());
handler.post(new Runnable(){
// your TextView goes here
})
Only the UI thread (main thread) can access UI elements
// Your message receiving class
...
message = new String(lmessage, 0, packet.getLength());
final String message_received = new String(lmessage, 0, packet.getLength());
...
MainActivity.context.runOnUiThread(new Runnable() {
#Override
public void run() {
MainActivity.textViewState.setText(message_received);
}
});
...
I found a solution based on both of your answers :) Thank you
MainActivity class:
public static Handler UIHandler;
static {
UIHandler = new Handler(Looper.getMainLooper());
}
public static void runOnUI(Runnable runnable) {
UIHandler.post(runnable);
}
receive class
MainActivity.runOnUI(new Runnable() {
public void run() {
MainActivity.textViewState.setText(message_received);
}
});
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 :)
I am writing an IRC Client. The socket connection to the IRC Server is handled via a service. I have managed to stabilize all the UI elements of the Activities in question during the orientation change, but somehow the socket that is maintained by the service is being closed during the change.
Here is what I believe to be the relevant code. Please let me know if you need to see more.
//This is the Service in question
public class ConnectionService extends Service{
private BlockingQueue<String> MessageQueue;
public final IBinder myBind = new ConnectionBinder();
public class ConnectionBinder extends Binder {
ConnectionService getService() {
return ConnectionService.this;
}
}
private Socket socket;
private BufferedWriter writer;
private BufferedReader reader;
private IRCServer server;
private WifiManager.WifiLock wLock;
private Thread readThread = new Thread(new Runnable() {
#Override
public void run() {
try {
String line;
while ((line = reader.readLine( )) != null) {
if (line.toUpperCase().startsWith("PING ")) {
SendMessage("PONG " + line.substring(5));
}
else
queueMessage(line);
}
}
catch (Exception e) {}
}
});
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
if(MessageQueue == null)
MessageQueue = new LinkedBlockingQueue<String>();
return Service.START_STICKY;
}
#Override
public IBinder onBind(Intent arg0) {
return myBind;
}
#Override
public boolean stopService(Intent name) {
try {
socket.close();
wLock.release();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return super.stopService(name);
}
#Override
public void onDestroy()
{//I put this here so I had a breakpoint in place to make sure this wasn't firing instead of stopService
try {
socket.close();
wLock.release();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
super.onDestroy();
}
public void SendMessage(String message)
{
try {
writer.write(message + "\r\n");
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
public String readLine()
{
try {
if(!isConnected())
return null;
else
return MessageQueue.take();
} catch (InterruptedException e) {
return "";
}
}
public boolean ConnectToServer(IRCServer newServer)
{
try {
//create a new message queue (connecting to a new server)
MessageQueue = new LinkedBlockingQueue<String>();
//lock the wifi
WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
wLock = wifiManager.createWifiLock(WifiManager.WIFI_MODE_FULL, "LockTag");
wLock.acquire();
server = newServer;
//connect to server
socket = new Socket();
socket.setKeepAlive(true);
socket.setSoTimeout(60000);
socket.connect(new InetSocketAddress(server.NAME, Integer.parseInt(server.PORT)), 10000);
writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
//run basic login scripts.
if(server.PASS != "")
SendMessage("PASS " + server.PASS);
//write nickname
SendMessage("NICK " + server.NICK);
//write username login
SendMessage("USER " + server.NICK + " 0 * :Fluffy IRC");
String line;
while ((line = reader.readLine( )) != null) {
if (line.indexOf("004") >= 0) {
// We are now logged in.
break;
}
else if (line.indexOf("433") >= 0) {
//change to alt Nick
if(!server.NICK.equals(server.ALT_NICK) && !server.ALT_NICK.equals(""))
{
server.NICK = server.ALT_NICK;
SendMessage("NICK " + server.NICK);
}
else
{
queueMessage("Nickname already in use");
socket.close();
return false;
}
}
else if (line.toUpperCase().startsWith("PING ")) {
SendMessage("PONG " + line.substring(5));
}
else
{
queueMessage(line);
}
}
//start the reader thread AFTER the primary login!!!
CheckStartReader();
if(server.START_CHANNEL == null || server.START_CHANNEL == "")
{
server.WriteCommand("/join " + server.START_CHANNEL);
}
//we're done here, go home everyone
} catch (NumberFormatException e) {
return false;
} catch (IOException e) {
return false;
}
return true;
}
private void queueMessage(String line) {
try {
MessageQueue.put(line);
} catch (InterruptedException e) {
}
}
public boolean isConnected()
{
return socket.isConnected();
}
public void CheckStartReader()
{
if(this.isConnected() && !readThread.isAlive())
readThread.start();
}
}
//Here are the relevant portions of the hosting Activity that connects to the service
//NOTE: THE FOLLOWING CODE IS PART OF THE ACTIVITY, NOT THE SERVICE
private ConnectionService conn;
private ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName name, IBinder service) {
conn = ((ConnectionService.ConnectionBinder)service).getService();
Toast.makeText(main_tab_page.this, "Connected", Toast.LENGTH_SHORT)
.show();
synchronized (_serviceConnWait) {
_serviceConnWait.notify();
}
}
#Override
public void onServiceDisconnected(ComponentName name) {
conn = null;
}
};
#Override
protected void onSaveInstanceState(Bundle state){
super.onSaveInstanceState(state);
state.putParcelable("Server", server);
state.putString("Window", CurrentTabWindow.GetName());
unbindService(mConnection);
}
#Override
protected void onDestroy()
{
super.onDestroy();
if(this.isFinishing())
stopService(new Intent(this, ConnectionService.class));
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_tab_page);
localTabHost = (TabHost)findViewById(R.id.tabHostMain);
localTabHost.setup();
localTabHost.setOnTabChangedListener(new tabChange());
_serviceConnWait = new Object();
if(savedInstanceState == null)
{//initial startup, coming from Intent to start
//get server definition
server = (IRCServer)this.getIntent().getParcelableExtra(IRC_WINDOW);
server.addObserver(this);
AddTabView(server);
startService(new Intent(this, ConnectionService.class));
}
else
{
server = (IRCServer)savedInstanceState.getParcelable("Server");
String windowName = savedInstanceState.getString("Window");
//Add Needed Tabs
//Server
if(!(windowName.equals(server.GetName())))
AddTabView(server);
//channels
for(IRCChannel c : server.GetAllChannels())
if(!(windowName.equals(c.GetName())))
AddTabView(c);
//reset each view's text (handled by tabChange)
if(windowName.equals(server.GetName()))
SetCurrentTab(server.NAME);
else
SetCurrentTab(windowName);
ResetMainView(CurrentTabWindow.GetWindowTextSpan());
//Rebind to service
BindToService(new Intent(this, ConnectionService.class));
}
}
#Override
protected void onStart()
{
super.onStart();
final Intent ServiceIntent = new Intent(this, ConnectionService.class);
//check start connection service
final Thread serverConnect = new Thread(new Runnable() {
#Override
public void run() {
if(!BindToService(ServiceIntent))
return;
server.conn = conn;
conn.ConnectToServer(server);
server.StartReader();
if(server.START_CHANNEL != null && !server.START_CHANNEL.equals(""))
{
IRCChannel chan = server.FindChannel(server.START_CHANNEL);
if(chan != null)
{
AddTabView(chan);
}
else
{
server.JoinChannel(server.START_CHANNEL);
chan = server.FindChannel(server.START_CHANNEL);
AddTabView(chan);
}
}
}
});
serverConnect.start();
}
private boolean BindToService(Intent ServiceIntent)
{
int tryCount = 0;
bindService(ServiceIntent, mConnection, Context.BIND_AUTO_CREATE);
while(conn == null && tryCount < 10)
{
tryCount++;
try {
synchronized (_serviceConnWait) {
_serviceConnWait.wait(1500);
}
}
catch (InterruptedException e) {
//do nothing
}
}
return conn != null;
}
Im not entirely certain what I am doing wrong there. Obviously there's something I'm missing, haven't found yet, or haven't even thought to check. What happens though is that after the orientation change my Send command gives me this message and nothing happens:
06-04 22:02:27.637: W/System.err(1024): java.net.SocketException: Socket closed
06-04 22:02:27.982: W/System.err(1024): at com.fluffyirc.ConnectionService.SendMessage(ConnectionService.java:90)
I have no idea when the socket is getting closed, or why.
Update
I have changed the code so that rather than binding to the service and using that to start it, instead I call startService and stopService at appropriate points as well as binding to it, on the thought that the service was being destroyed when the binding was lost. This is working exactly like it was before I changed it. The socket still closes on an orientation change, and I have no idea why.
Update :- Code and description
I added the code changes recently made for Start/Stop service and START_STICKY. I also recently read a very good article explaining how the orientation change process flow works and why its NOT a bad idea to add the android:configChanges="orientation|screenSize" line to your manifest. So this fixed the orientation issue, but its still doing the same thing if I put the activity into background mode, and then bring it back to the foreground. That still follows the same Save/Destroy/Create process that the orientation does without that manifest line...and it still closes my socket, and I still don't know why.
I do know that it doesn't close the socket until the re-create process...I know this because the message queue will display messages that were received while the app was in the background, but once I bring it back forward it closes the socket and nothing else can be sent or received.
'Socket closed' means that you closed the socket and then continued to use it. It isn't a 'disconnect'.
You need to put something into that catch block. Never just ignore an exception. You might get a surprise when you see what the exception actually was.
NB Socket.isConnected() doesn't tell you anything about the state of the connection: only whether you have ever connected the Socket. You have, so it returns true.
When I click the first time on login button, data send to server and server received data in return on first click data not show on android client screen. When I pressed login button again it again send data and then it show data on client screen... plz help me. Why data is received on secind click i want my data recived on my first click?
Here is the code :
Client tcpip code...
public class SockProg {
private Socket socket;
DataOutputStream dataOutputStream;
DataInputStream dataInputStream;
String data;
String serverip = "192.168.1.7";
int serverport = 4444;
public void connetToServer(){
try {
socket = new Socket(serverip, serverport);
Log.i("AsyncTank", "doInBackgoung: Created Socket");
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (socket.isConnected()) {
try {
dataOutputStream = new DataOutputStream(
socket.getOutputStream());
dataInputStream = new DataInputStream(socket.getInputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void writeToStream(String message) {
try {
if (socket.isConnected()){
dataOutputStream.writeUTF(message.toString());
} else {
Log.i("AsynkTask", "writeToStream : Cannot write to stream, Socket is closed");
}
} catch (Exception e) {
Log.i("AsynkTask", "writeToStream : Writing failed");
}
}
public String readFromStream() {
String ret = null;
try {
if (socket.isConnected()) {
Log.i("AsynkTask", "readFromStream : Reading message");
ret=dataInputStream.readUTF();
Log.i("AsynkTask", "readFromStream : read "+ret);
} else {
Log.i("AsynkTask", "readFromStream : Cannot Read, Socket is closed");
}
} catch (Exception e) {
Log.i("AsynkTask", "readFromStream : Reading failed"+e.getClass());
}
return ret;
}
public void CloseSockets(){
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataOutputStream != null) {
try {
dataOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataInputStream != null) {
try {
dataInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
here is the code of sychronized thread
public class TCP implements Runnable {
String data;
SockProg sp;
Thread thh;
private static String rdata;
public TCP(SockProg spr, String val) {
sp = spr;
data = val;
thh = new Thread(this);
thh.start();
}
#Override
public void run() {
synchronized(sp) { // synchronized block
//rdata= sp.DataSendRecive(data);
sp.connetToServer();
sp.writeToStream(data);
rdata=sp.readFromStream();
sp.CloseSockets();
}
}
public static String getData(){
return rdata;
}
}
here is code of Login Activity...
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
msg = (TextView) findViewById(R.id.msg_log);
login = (Button) findViewById(R.id.btn_login);
login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// try{
txtph = (EditText) findViewById(R.id.txt_phnum);
txtpass = (EditText) findViewById(R.id.txt_pass);
ph = txtph.getText().toString();
pass = txtpass.getText().toString();
int ch = 0;
if (ph.equals("") || ph == null) {
msg.setText("Please Enter Mobile Number....\n");
ch++;
}
if (pass.equals("") || pass == null) {
if (ch == 0) {
msg.setText("Please Enter your Password....\n");
} else {
msg.append("Please Enter your Password....\n");
}
ch++;
}
if (ch == 0) {
ArrayList<String> ph_pass = new ArrayList<String>();
ph_pass.add(0, "LoginAccount");
ph_pass.add(1, ph);
ph_pass.add(2, pass);
SockProg sp=new SockProg();
TCP t=new TCP(sp, ph_pass.toString());
data=t.getData();
msg.setText(data);
}
}
});
}
This looks like a classic case of asynchronous coding delay. The TCP class is a runnable and therefor when it is called the first time (the first click on the login button) it starts running, but the Thread does not have enough time to finish
rdata=sp.readFromStream();
in the run() method, therefor data=t.getData(); does not return anything useful. The second click, provides the runnable with enough time populate the rdata with some data and therefor your program works.
When working with asynchrounous code, you need a better way to wait for code to complete what it is doing.
Why is rdata a static type? Make it non-static and then change the getData() method like this:
public synchronized String getData()
I'm working on an android Quiz app with connection to a server over a socket. On the client side (Android device) I check in a while loop the answers which are given by a server (Java server). The connection and the receiving of the answer all goes good. The problem is that in my class to check for answers there's a bug. To give more information I will include a part of the code here:
public void startClient(){
checkValue = new Thread(new Runnable(){
#Override
public void run() {
try
{
final int PORT = 4444;
final String HOST = "192.168.1.118";
Socket SOCK = new Socket(HOST, PORT);
Log.e("success", "You connected to: " + HOST);
quizClient = new QuizClient(SOCK);
//Send the groupname to the list
PrintWriter OUT = new PrintWriter(SOCK.getOutputStream());
OUT.println(groupName);
OUT.flush();
Thread X = new Thread(quizClient);
X.start();
connected = true;
}
catch(Exception X)
{
Log.e("connection error", "Error: ", X);
}
}
});
checkValue.start();
}
public void testvalue(){
Thread thread = new Thread(new Runnable(){
#Override
public void run() {
try {
while(true){
if(message != null && !message.matches("")){
Thread.sleep(1000);
Log.e("receive", message);
buffer = message;
message = "";
Message msg = new Message();
String textTochange = buffer;
msg.obj = textTochange;
mHandler.sendMessage(msg);
Thread.sleep(3000);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
thread.start();
}
Handler mHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
String text = (String)msg.obj;
//call setText here
//String[] myStringArray = new String[];
value.clear();
String[] items = text.split(";");
for (String item : items)
{
value.add(item);
Log.e("message", item);
//System.out.println("item = " + item);
}
if(value.get(0).equals("1")){
questionGroup.setVisibility(View.INVISIBLE);
sendAnswer.setVisibility(View.INVISIBLE);
answer.setVisibility(View.INVISIBLE);
question.setText("");
question.setText(value.get(2));
rad1.setText(value.get(3));
rad2.setText(value.get(4));
rad3.setText(value.get(5));
rad4.setText(value.get(6));
questionGroup.setVisibility(View.VISIBLE);
sendAnswer.setVisibility(View.VISIBLE);
} else if (value.get(0).equals("2")){
questionGroup.setVisibility(View.INVISIBLE);
sendAnswer.setVisibility(View.INVISIBLE);
answer.setVisibility(View.INVISIBLE);
question.setText("");
question.setText(value.get(2));
answer.setVisibility(View.VISIBLE);
sendAnswer.setVisibility(View.VISIBLE);
} else
{
questionGroup.setVisibility(View.INVISIBLE);
sendAnswer.setVisibility(View.INVISIBLE);
answer.setVisibility(View.INVISIBLE);
question.setText(text);
}
}
};
#Override
protected void onStop()
{
if (connected == true){
try {
quizClient.DISCONNECT();
} catch (IOException e) {
e.printStackTrace();
}
}
if(checkValue != null)
{
checkValue.interrupt();
}
super.onStop();
closeApplication();
}
So I make a new instance of this class (where I actually check the incoming stream of data)
public class QuizClient implements Runnable {
//Globals
Socket SOCK;
Scanner INPUT;
Scanner SEND = new Scanner(System.in);
PrintWriter OUT;
public QuizClient(Socket X)
{
this.SOCK = X;
}
public void run()
{
try
{
try
{
INPUT = new Scanner(SOCK.getInputStream());
OUT = new PrintWriter(SOCK.getOutputStream());
OUT.flush();
CheckStream();
}
finally
{
SOCK.close();
}
}
catch(Exception X)
{
Log.e("error", "error: ", X);
}
}
public void DISCONNECT() throws IOException
{
OUT.println("DISCONNECT");
OUT.flush();
SOCK.close();
}
public void CheckStream()
{
while(true)
{
RECEIVE();
}
}
public void RECEIVE()
{
if(INPUT.hasNext())
{
String MESSAGE = INPUT.nextLine();
if(MESSAGE.contains("#?!"))
{
}
else
{
QuizActivity.message = MESSAGE;
Log.e("test", MESSAGE);
}
}
}
public void SEND(String X)
{
OUT.println(X);
OUT.flush();
}
}
So the bug persist I think in the following class:
public void testvalue(){
Thread thread = new Thread(new Runnable(){
#Override
public void run() {
try {
while(true){
if(message != null && !message.matches("")){
Thread.sleep(1000);
Log.e("receive", message);
buffer = message;
message = "";
What I do here is make a thread and check if the "message" is not equals at null. The message come from the other class:
public void RECEIVE()
{
if(INPUT.hasNext())
{
String MESSAGE = INPUT.nextLine();
if(MESSAGE.contains("#?!"))
{
}
else
{
QuizActivity.message = MESSAGE;
Now most of the time this works good but there are 2 problems. When I go out of the page it disconnect from the server (works) I go back on the page and connect again to the server but this time I don't get any values on the screen (receiving is okj but for one of the other reason it does not go good in my handler). Also get an indexoutofboundexception after a time:
question.setText(value.get(2));
A second problem occurs some time while the program runs. There are moments that I also don't get a value on my interface while it correctly receive the input.
So my guess is that my solution of the thread to read in the values is not the best way to handle it. So now I ask to people with more experience what I can do to make this work without major problems? You need to know the connection works and I get the value in my QuizClient class. So the problem need to be in my main class.
My oncreate class:
#Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_quiz);
selectgroep = (Spinner) findViewById(R.id.groepen);
questionGroup = (RadioGroup) findViewById(R.id.QuestionGroup);
sendAnswer = (Button) findViewById(R.id.sendAnswer);
rad1 = (RadioButton) findViewById(R.id.radio0);
rad2 = (RadioButton) findViewById(R.id.radio1);
rad3 = (RadioButton) findViewById(R.id.radio2);
rad4 = (RadioButton) findViewById(R.id.radio3);
answer = (EditText) findViewById(R.id.textanswer);
questionGroup.setVisibility(View.INVISIBLE);
sendAnswer.setVisibility(View.INVISIBLE);
answer.setVisibility(View.INVISIBLE);
try {
connect();
} catch (InterruptedException e) {
e.printStackTrace();
}
//Code na het drukken op de knop
startserver = (Button) findViewById(R.id.startserver);
startserver.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
startClient();
getID();
testvalue();
}
});
sendAnswer.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Stuur antwoord door en sluit alles af
questionGroup.setVisibility(View.INVISIBLE);
sendAnswer.setVisibility(View.INVISIBLE);
answer.setVisibility(View.INVISIBLE);
answer.setText("");
rad1.setChecked(true);
rad1.setText("");
rad2.setText("");
rad3.setText("");
rad4.setText("");
question.setText("Wachten op server ... ");
}
});
}
Thank you in advance,
Thomas Thooft