I'm trying to write a simple client/server program, where the client is an android app and the server is a Raspberry Pi 4. All I want to do is allow the client to type a message and have the Raspberry Pi display the message on the terminal. However, my app keeps throwing an exception at the out.writeObject(message_text) line in the sendMessage() method.
public class MainActivity extends AppCompatActivity {
private EditText message;
private Button send;
private ObjectOutputStream out;
private Socket socket;
private String raspi_ip = "enter ip here";
private int raspi_portnum = 12345;
Client client;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
message = findViewById(R.id.message_text);
send = findViewById(R.id.send_button);
try{
client = new Client(raspi_ip,raspi_portnum);
client.start();
} catch (Exception e){
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("Error! ").setMessage("Couldn't connect to server.").setNeutralButton("OK", null).create().show();
}
send.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
client.sendMessage();
}
});
}
private void closeConnection(){
try{
out.close();
socket.close();
} catch (Exception e){
e.printStackTrace();
}
}
#Override
protected void onStop(){
super.onStop();
closeConnection();
}
private class Client extends Thread {
private String ip_address;
private int port_number;
public Client(String ipaddress,int portnum){
this.ip_address = ipaddress;
this.port_number = portnum;
}
#Override
public void run() {
super.run();
connectToServer(ip_address,port_number);
}
public void connectToServer(String ipaddress, int portnum){
try{
socket = new Socket(InetAddress.getByName(ipaddress),portnum);
out = new ObjectOutputStream(socket.getOutputStream());
out.flush();
}catch (Exception e){
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("Error! ").setMessage("Couldn't connect to server.").setNeutralButton("OK", null).create().show();
}
}
public void sendMessage(){
String message_text = message.getText().toString();
try{
out.writeObject(message_text);
out.flush();
} catch (Exception e) {
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("Error! ").setMessage("IO Exception.").setNeutralButton("OK", null).create().show();
}
}
}
}
Here is the server side java program:
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class RaspPiServer {
private ServerSocket server;
public RaspPiServer(){
}
public static void main(String[] args){
RaspPiServer server = new RaspPiServer();
server.runServer();
}
public void runServer(){
try{
server = new ServerSocket(12345,100);
while (true){
new Controller(server.accept()).start();
}
} catch(Exception e){
e.printStackTrace();
}
}
private class Controller extends Thread {
private Socket socket;
private ObjectInputStream input;
private String in;
public Controller(Socket socket){
this.socket = socket;
System.out.println("New client at " + socket.getRemoteSocketAddress());
}
#Override
public void run(){
try{
input = new ObjectInputStream(socket.getInputStream());
while (!(in = (String)input.readObject()).equals("close")){
System.out.println(in);
}
} catch(Exception e){
e.printStackTrace();
} finally {
closeConnection();
System.out.println("Connection with client # " + socket.getRemoteSocketAddress() + " closed");
}
}
private void closeConnection() {
try {
input.close();
socket.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
Is there an easy fix here, or am I missing something bigger?
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 am creating an android application in which i am creating socket connection in one activity and using Shared Preferences and in another activity I am fetching the socket variables to do furthur jobs but its not working as i am expected
My question is how can i use my exixting socket connection in different actvities i have searched about it Got some terms like singltone class,Aysnc task, But i am not getting it,if singltone is proper way to use socket connetion in different activities then How can i use singlton class in following code please suggest me changes...!!!
Otherwise is it proper way am i doing Shared PRef as following??also suggest some changes!!!
UPDATE: Tagged singlton for suggestions
So here is First Activity
public class ipInfo extends AppCompatActivity {
EditText ipaddress;
String IPADD;
Integer PORT=null;
EditText portnum;
Button connect_btn;
StrictMode.ThreadPolicy policy;
Socket cs = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_ipinfo);
policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
ipaddress = (EditText)findViewById(R.id.editText);
portnum = (EditText)findViewById(R.id.editText2);
connect_btn =(Button)findViewById(R.id.button);
ip_check();
}
public void ip_check(){
connect_btn.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
IPADD=ipaddress.getText().toString();
PORT=Integer.parseInt(portnum.getText().toString());
try { cs = new Socket();
cs.connect(new InetSocketAddress(IPADD, PORT), 2000);
SharedPreferences sharedPreferences = getSharedPreferences("ipstore", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("ipadd",IPADD);
editor.putInt("port",PORT);
editor.commit();
if(cs.isConnected()) {
Toast.makeText(ipInfo.this, "Connected", Toast.LENGTH_SHORT).show();
Intent inst = new Intent(ipInfo.this,homeActivity.class);
startActivity(inst);
finish();
}
}catch (IOException e)
{Toast.makeText(ipInfo.this,"Server is disconnected\n",Toast.LENGTH_SHORT).show();
}catch (Exception e)
{Toast.makeText(ipInfo.this,e.getMessage(),Toast.LENGTH_SHORT).show();}
}
}
);
}
}
from this activity am fetching values in following activity
public class PowerActivity extends AppCompatActivity {
Button restart,shutdown,logof,sleep,abort;
StrictMode.ThreadPolicy policy;
Socket cs = null;
DataOutputStream out=null;
String SERVERIP;
int PORT;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_power);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
restart = (Button)findViewById(R.id.restart);
shutdown = (Button)findViewById(R.id.shutdown);
logof = (Button)findViewById(R.id.logof);
sleep = (Button)findViewById(R.id.sleep);
abort = (Button)findViewById(R.id.abort);
SharedPreferences sharedPreferences=getSharedPreferences("ipstore", Context.MODE_PRIVATE);
SERVERIP =sharedPreferences.getString("ipadd","");
PORT=sharedPreferences.getInt("port", 8002);
Toast.makeText(this,"Working"+SERVERIP+"\n"+PORT,Toast.LENGTH_LONG).show();//this line working fine
policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
remotecmnd();
}
public void remotecmnd(){
restart.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
//restart code
try{
cs = new Socket(SERVERIP,PORT);
try{
out = new DataOutputStream(cs.getOutputStream());
out.writeUTF("restart");
Toast.makeText(PowerActivity.this, "RESTART SUCCESS", Toast.LENGTH_LONG).show();
} catch (Exception ea) {
Toast.makeText(PowerActivity.this, ea.getMessage(), Toast.LENGTH_LONG).show();
}
}catch (IOException e) {
Toast.makeText(PowerActivity.this, e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}
);
}
}
here is server part code
public class serverbackend extends Thread implements Runnable{
public static int SERVERPORT = 8002;
public boolean running = false;
public volatile boolean stop = false;
public Socket client = null;
ServerSocket sc = null;
String value;
public static void main(String[] args) {
mwcobj = new MainWindowController();
}
#Override
public void run() {
super.run();
running = true;
try {
System.out.println("Server Has Started........ \nWaiting for client........");
sc = new ServerSocket(SERVERPORT);
try {
while (!stop && running) {
client = sc.accept();
System.out.println("Connection Accepted......");
DataInputStream dis = new DataInputStream(client.getInputStream());
value = dis.readUTF();
switch (value) {
//Restart the system
case "restart":
System.out.println("Restarting");
Runtime.getRuntime().exec("shutdown -r -t 10");
break;
//some extra code
default:
break;
}
}
} catch (IOException e) {
System.out.println("Inner try catch "+e.getMessage());
}
} catch (IOException e) {
System.out.println("Final try catch error "+e.getMessage());
}
}
public void requestStop(){
try{
stop = true;
sc.close();
System.out.println("Server Has Stopped");
}catch(IOException e){System.out.println("Server Stopped "+e.getMessage());}
}
}
In my opinion, I created a bluetooth communication app,where I get the same problem,
The answer for the this is to use getter and setter methods. It is very easy to set socket and get socket from other java class rather than sending across activities , If I came across other methods I will definitely will tell you on that..
Using getter setter will work for you I beleive.
public class getset
{
static BluetoothSocket sock;
getset(BluetoothSocket sock)
{
this.sock=sock;
}
public static synchronized BluetoothSocket getSock() {
return sock;
}
public static synchronized void setSock(BluetoothSocket sock) {
getset.sock = sock;
}
}
In the place of using shared preference
setSock(socket); //socket is the Bluetoothsocket which you have to save
Bluetoothsocket socket=getSock(); // to get value from the socket
refer https://teamtreehouse.com/community/how-do-you-add-getters-and-setter-in-android-java
I am trying to create a connection between two applications using android. I have tried to use sockets to connect. I have created two application
One which accepts the connection when client wants to connect
and another application that requests to connect.
I have successfully run this code in same manner in pc in java in pc network. Is the way of connecting to android also same?
My server class implementation
public class MainActivity extends AppCompatActivity {
private Button startButton;
private ServerSocket server;
private Socket connection;
private TextView statusText;
private ObjectOutputStream output;
private ObjectInputStream input;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
statusText=(TextView)findViewById(R.id.statusText);
startButton=(Button)findViewById(R.id.startButton);
startButton.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
startRunning();
}
}
);
}
private void startRunning() {
try{
server=new ServerSocket(8080);
while(true)
{
try{
waitForConnection();
setUpStreams();
whileChatting();
}catch(Exception e){}
}
} catch(Exception e){}
}
public void waitForConnection()
{
setMyStatus("Waiting for client to connect...");
try {
connection= server.accept();
setMyStatus("Now connected to "+ connection.getInetAddress().getHostName());
} catch (IOException e) {
e.printStackTrace();
}
}
public void setUpStreams()
{
try {
output= new ObjectOutputStream(connection.getOutputStream());
output.flush();
input= new ObjectInputStream(connection.getInputStream());
setMyStatus("Streams are now setup. Ready to go...");
} catch (IOException e) {
e.printStackTrace();
}
}
public void whileChatting()
{
setMyStatus("You can now start chatting...");
}
public void setMyStatus(String msg) {
statusText.setText(msg);
}
}
I will use the tasks like async task later. But i am just trying to set up connection in these application.
My client implementation goes like this
public class MainActivity extends AppCompatActivity {
private Button startButton;
private Socket connection;
private TextView statusText;
public ObjectOutputStream output;
public ObjectInputStream input;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
statusText=(TextView)findViewById(R.id.statusText);
startButton=(Button)findViewById(R.id.startButton);
startButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startRunning();
}
});
}
private void startRunning() {
connectToServer();
setUpStreams();
whileChatting();
}
public void connectToServer()
{
setMyStatus("Connecting to server. Please wait...");
try {
connection= new Socket(InetAddress.getByName("127.0.0.1"),8080);
setMyStatus("Connected to Server."+ connection.getInetAddress().getHostName());
} catch (IOException e) {
e.printStackTrace();
}
}
public void setUpStreams()
{
try {
output= new ObjectOutputStream(connection.getOutputStream());
output.flush();
input= new ObjectInputStream(connection.getInputStream());
setMyStatus("Streams are now setup. Ready to go...");
} catch (IOException e) {
e.printStackTrace();
}
}
public void whileChatting()
{
setMyStatus("You can now start chatting...");
}
public void setMyStatus(String msg) {
statusText.setText(msg);
}
}
The error I got is in the case of client that tries to connect to server
java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.OutputStream java.net.Socket.getOutputStream()' on a null object reference
at com.myapp.client.clientdemo.MainActivity.setUpStreams(MainActivity.java:71)
at com.myapp.client.clientdemo.MainActivity.startRunning(MainActivity.java:46)
at com.myapp.client.clientdemo.MainActivity.access$000(MainActivity.java:16)
at com.myapp.client.clientdemo.MainActivity$1.onClick(MainActivity.java:33)
It's because "connection" was never created. Probably because it failed to connect or it timed out and it moved on to the next code. If it timed out or didn't connect, then you need to catch that exception and retry to connect before moving on with your later code.
Socket can be tricky if you do not catch all the erroneous states they can get into.
simply wrap your try and catch with a while loop until the condition is met like this:
while(!connected & !closed){
try {
connection= new Socket(InetAddress.getByName("127.0.0.1"),8080);
connected = true;
//now it is connected and will exit the loop and continue with other code
} catch (SocketTimeoutException socketTimeoutException) {
//add this for safety
} catch (IOException e) {
e.printStackTrace();
}
}
I need to create an application using android socket level programming, I created a connection between server and client but I need to show waiting server IP list at client side and select one IP from the list and establish a connection between them.
Here is my code for server side
public class Server extends AppCompatActivity {
private static final String TAG = "ServerActivity";
private TextView tvServerStatus;
private TextView recievemsg;
InetAddress receiverAddress;
public static String SERVERIP = "";
DatagramSocket datagramSocket;
public static final int SERVERPORT = 8080;
private Handler handler = new Handler();
Handler updateConversationHandler;
private ServerSocket serverSocket;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_server);
updateConversationHandler = new Handler();
tvServerStatus = (TextView) findViewById(R.id.tvServerStatus);
recievemsg=(TextView)findViewById(R.id.send_msg);
SERVERIP = getLocalIpAddress();
Thread fst = new Thread(new ServerThread());
fst.start();
try {
datagramSocket = new DatagramSocket(8080);
byte[] buffer = "0123456789".getBytes();
byte[] address=SERVERIP.getBytes();
receiverAddress = InetAddress.getByAddress(address);
DatagramPacket packet = new DatagramPacket(
buffer, buffer.length, receiverAddress, 8080);
datagramSocket.send(packet);
} catch (SocketException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private String getLocalIpAddress() {
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;
}
public class ServerThread implements Runnable {
#Override
public void run() {
try {
Log.e(TAG, "Server IP: " + SERVERIP);
if (SERVERIP != null) {
handler.post(new Runnable() {
#Override
public void run() {
tvServerStatus.setText("Listening On Ip: " + SERVERIP);
}
});
serverSocket = new ServerSocket(SERVERPORT);
while (!Thread.currentThread().isInterrupted()) {
{
try {
// LISTEN FOR INCOMING CLIENTS
Socket client = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(client);
new Thread(commThread).start();
// Log.e(TAG, "Client Socket: " + client);
// new Clients_Handle(client, ROOT_DIRECTORY).start();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
} else {
handler.post(new Runnable() {
#Override
public void run() {
tvServerStatus.setText("Couldn't detect internet connection.");
}
});
}
} catch (IOException e) {
handler.post(new Runnable() {
#Override
public void run() {
tvServerStatus.setText("Error");
}
});
e.printStackTrace();
}
}
}
class CommunicationThread implements Runnable {
private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
try {
this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while (!Thread.currentThread().isInterrupted()) {
try {
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class updateUIThread implements Runnable {
private String msg;
public updateUIThread(String str) {
this.msg = str;
}
#Override
public void run() {
recievemsg.setText(recievemsg.getText().toString() + "Client Says: " + msg + "\n");
}
}
#Override
protected void onDestroy() {
super.onDestroy();
try {
// MAKE SURE YOU CLOSE THE SOCKET UPON EXITING
serverSocket.close();
Log.e(TAG,"Socket Closed");
} catch (IOException e) {
e.printStackTrace();
}
}
}
And here is my client side code
public class Clientss extends AppCompatActivity {
private static final String TAG = "Client_Activity";
private EditText etServerIp;
private EditText etMsg;
private Button btnConnectClients;
private Button btnSendMsg;
private TextView textIn;
private String serverIpAddress = "";
private String t;
private boolean connected = false;
DatagramSocket datagramSocket;
DatagramPacket packet;
private Socket socket;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_clientss);
Log.e(TAG, "ONCREATE METHOD");
textIn = (TextView)findViewById(R.id.txt_msg);
initializations();
eventClickListener();
try {
datagramSocket = new DatagramSocket(8080);
byte[] buffer = new byte[10];
packet = new DatagramPacket(buffer, buffer.length);
datagramSocket.receive(packet);
byte[] buff = packet.getData();
textIn.setText(buff.toString());
System.out.println("this is incoming ip"+buff.toString());
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// textIn.setText(t);
}
private void eventClickListener() {
btnConnectClients.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (!connected) {
serverIpAddress = etServerIp.getText().toString().trim();
connectsClient();
}
}
});
btnSendMsg.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String msg = etMsg.getText().toString().trim();
ClientResponseTask clientResponseTask=new ClientResponseTask(msg);
clientResponseTask.execute();
}
});
}
private void connectsClient() {
if (!serverIpAddress.equals("")) {
Thread cThread = new Thread(new ClientThread());
cThread.start();
}
}
private void initializations() {
etServerIp = (EditText) findViewById(R.id.etServerIp);
etMsg = (EditText) findViewById(R.id.etMsg);
btnSendMsg = (Button) findViewById(R.id.btnMsgSend);
btnConnectClients = (Button) findViewById(R.id.btnConnect);
}
private class ClientThread implements Runnable {
#Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
Log.e(TAG, "C: Connecting...");
socket = new Socket(serverAddr, Server.SERVERPORT);
System.out.println("this is socket"+socket);
connected = true;
Message msg = handler.obtainMessage();
msg.arg1 = 1;
handler.sendMessage(msg);
//showToast("");
Log.e(TAG, "C: Connected..." + socket);
} catch (Exception e) {
Log.e(TAG, "C: Error", e);
connected = false;
}
}
}
private final Handler handler = new Handler() {
public void handleMessage(Message msg) {
if(msg.arg1 == 1)
Toast.makeText(getApplicationContext(),"Connected...", Toast.LENGTH_LONG).show();
}
};
#Override
protected void onDestroy() {
if (socket != null) try {
socket.close();
Log.e(TAG, "C: Socket Closed.");
} catch (IOException e) {
e.printStackTrace();
} finally
{
try
{
socket.close();
}
catch(Exception e){}
}
super.onDestroy();
}
protected class ClientResponseTask extends AsyncTask<Void,Void,Void> {
String msg;
ClientResponseTask(String msg){
this.msg=msg;
}
#Override
protected Void doInBackground(Void... params) {
if (connected) {
try {
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
out.println(msg);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (Exception e) {
Log.e(TAG, "Error", e);
}
}
else {
connectsClient();
}
return null;
}
}
}
Please help me to find a solution.
I'm trying for sometime now and I cant figure it out why this is not working.
CLIENT:
public class MainActivity extends AppCompatActivity {
private Socket socket;
public static final int PORT = 6000;
public static final String server_IP = "192.168.2.30";
public String mensagem = null;
public String mensagem_final = null;
Button btn_conetar;
TextView txt;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_conetar = (Button) findViewById(R.id.btn_conetar);
txt = (TextView) findViewById(R.id.txt);
Thread t = new Thread() {
public void run() {
try {
while(!isInterrupted())
{
Thread.sleep(1000);
runOnUiThread(new Runnable() {
#Override
public void run() {
txt.setText(mensagem_final);
}
});
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
t.start();
}
public void onClick(View view)
{
new Thread((new ClientThread())).start();
//Intent i = new Intent(MainActivity.this,Main2Activity.class);
// startActivity(i);
}
//Thread que inicia o socket
class ClientThread implements Runnable
{
#Override
public void run() {
try
{
InetAddress serveradress = InetAddress.getByName(server_IP);
Log.e("TCP","A conetar...");
socket = new Socket(serveradress,PORT);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while((mensagem = in.readLine()) != null)
{
mensagem_final += mensagem;
}
if(in.readLine() == null)
{
Log.e("TCP","Nao tem mensagens");
}
Log.e("MSG",mensagem);
socket.close();
}
catch (UnknownHostException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
}
}
}
Server:
Servidor servidor = new Servidor();
servidor.serverthread();
class Servidor
{
public void serverthread()
{
Thread serverthread = new Thread(server);
serverthread.Start();
}
public void server()
{
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
TcpListener tcplistener = new TcpListener(IPAddress.Any, 6000);
tcplistener.Start();
TcpClient tcpclient = tcplistener.AcceptTcpClient();
byte[] data = new byte[1024];
NetworkStream ns = tcpclient.GetStream();
string welcome = "Ola";
data = Encoding.ASCII.GetBytes(welcome);
ns.Write(data, 0, data.Length);
}
}
Any idea why I cant receive the string "Ola" in my android application? It doesnt give me any error, it just doesnt do anything.
My internet's default adress is 192.168.2.1.
Good links are also welcome.