I am trying to establish a connection between an Android Application and a Python script via sockets.
This Java code works absolutely fantastic with my Python server.
import java.io.*;
import java.net.*;
public class client {
public static void main(String[] args) {
try{
Socket s=new Socket("localhost",5000);
DataOutputStream dout=new DataOutputStream(s.getOutputStream());
dout.writeUTF("Hello Server");
dout.flush();
dout.close();
s.close();
}catch(Exception e){System.out.println(e);}
}
}
However, when I try to implement it in my Android application (see below), I have the feeling that the doInBackground() is not even called:
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import java.io.DataOutputStream;
import java.net.Socket;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView myText = (TextView) findViewById(R.id.TextView1);
Connect myConnect = new Connect();
myConnect.execute();
String myResult = Integer.toString(myConnect.getResult());
myText.setText(myResult);
}
}
class Connect extends AsyncTask<Void, Void, Integer> {
int result = 0;
#Override
protected void onPreExecute(){
result = 1;
}
#Override
protected Integer doInBackground(Void... params) {
try{
result = 2;
Socket s=new Socket("localhost",5000);
DataOutputStream dout = new DataOutputStream(s.getOutputStream());
dout.writeUTF("Hello Server");
dout.flush();
dout.close();
s.close();
}catch(Exception e){
result = -1;
return -1;
}
result = 3;
return 3;
}
#Override
protected void onProgressUpdate(Void... values) {
}
int getResult(){
return result;
}
}
What am I missing here to make it work?
Socket s=new Socket("localhost",5000);.
That should be
Socket s=new Socket("10.0.2.2",5000);
when using an emulator.
Related
So basically I want to create some kind of controller for my pc, where on pc, runs java socket server. The server is working, I have tried it. Also, Port Forwarding in the router is allright. Source code is here :
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
public class Server {
public static final String ANSI_RESET = "\u001B[0m";
public static final String ANSI_GREEN = "\u001B[32m";
public static final String ANSI_BOLD = "\033[1m";
public static final String ANSI_RED = "\u001B[31m";
public static void main(String[] args) throws IOException {
// Creating server instance
ServerSocket serverSocket = new ServerSocket(2000);
Socket socket = serverSocket.accept();
System.out.println(ANSI_GREEN + "Controller connected" + ANSI_RESET);
// Input Output streams
DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream());
String command = "";
do {
command = dataInputStream.readUTF();
switch (command.trim()){
case "volume up":
Runtime.getRuntime().exec("cmd /c start src\\sk\\dzurik\\main\\volup.bat");
break;
case "volume down":
Runtime.getRuntime().exec("cmd /c start src\\sk\\dzurik\\main\\voldown.bat");
break;
default:
// Unknown command
break;
}
}while (!command.equals("stop"));
socket.close();
System.out.println(ANSI_RED + "Controller disconnected" + ANSI_RESET);
}
}
And it is supposed to interact with the android app, but I got an error and I can't quite figure out why is that so, here is the source code for ActivityMain :
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
public class MainActivity extends AppCompatActivity {
private boolean connected;
private DataOutputStream dataOutputStream;
private Socket socket;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Pripájanie na server
try {
socket = new Socket("172.0.0.1",2000);
dataOutputStream = new DataOutputStream(socket.getOutputStream());
} catch (IOException e) {
Toast.makeText(MainActivity.this, "Not Connected!",
Toast.LENGTH_LONG).show();
}
Button VolumeUp = (Button) findViewById(R.id.VolumeUpButton);
VolumeUp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
send("volume up");
} catch (IOException e) {
e.printStackTrace();
}
}
});
Button VolumeDown = (Button) findViewById(R.id.VolumeDownButton);
VolumeDown.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
send("volume down");
} catch (IOException e) {
e.printStackTrace();
}
}
});
Button DisconnectButton = (Button) findViewById(R.id.DisconnectButton);
DisconnectButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
send("stop");
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
public void send(String command) throws IOException {
if (socket != null){
dataOutputStream.writeUTF(command);
}
else Toast.makeText(MainActivity.this, "Socket is not defined",
Toast.LENGTH_SHORT).show();
}
public void disconnect() throws IOException {
if (socket != null){
socket.close();
}
else Toast.makeText(MainActivity.this, "Socket is not defined",
Toast.LENGTH_SHORT).show();
}
}
So if you could help me with it, I would be thankful, <3
Well the reason for that was silly. When I'm loading data from Stream it says nextLine which means the ending point is \n so I could never get that line because I haven't put it there.
So,It's like the title Say's i have created a Simple android Socket server and Client which Connects over Wifi. Both devices are on the same Wifi Network. The Server Shows the IP Address on which it host the connection....And in the client You have to write the IP Address on which Server is hosted.....
So, My problem is when i am Entering The IP Address in the Client The Server shows "Connected". But when i start to send messages it doesn't send the message to other side neither Server to Client nor Client to server.
//#Server Java File
package inc.teckzy.wif_chat;
import android.net.wifi.WifiManager;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.format.Formatter;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
public class Helper extends AppCompatActivity {
EditText smessage;
TextView chat,display_status;
String str,msg="";
int serverport = 6666;
ServerSocket serverSocket;
Socket client;
Handler handler = new Handler();
WifiManager wmanager;
Boolean Alive;
DataOutputStream out;
DataInputStream in;
Button button_sent;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_helper);
wmanager = (WifiManager) getSystemService(WIFI_SERVICE);
#SuppressWarnings("deprecation")
String ip = Formatter.formatIpAddress(wmanager.getConnectionInfo().getIpAddress());
smessage = (EditText) findViewById(R.id.smessage);
chat = (TextView) findViewById(R.id.chat);
display_status = (TextView) findViewById(R.id.display_status);
Thread serverThread = new Thread(new serverThread());
serverThread.start();
Alive = serverThread.isAlive();
display_status.setText("Hosted on: " + ip);
button_sent = (Button) findViewById(R.id.button_sent);
button_sent.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Thread sentThread = new Thread(new sentMessage());
sentThread.start();
}
});
}
class sentMessage implements Runnable{
#Override
public void run() {
try{
client = serverSocket.accept();
out = new DataOutputStream(client.getOutputStream());
str = smessage.getText().toString();
msg = msg+"\n Server:" +str;
handler.post(new Runnable()
{
#Override
public void run()
{
chat.setText(msg);
}
});
out.writeBytes(str);
out.flush();
out.close();
client.close();
}catch(IOException e){}
}
}
public class serverThread implements Runnable {
#Override
public void run() {
try {
while (true) {
serverSocket = new ServerSocket(serverport);
client = serverSocket.accept();
handler.post(new Runnable() {
#Override
public void run() {
display_status.setText("Connected");
}
});
/*******************************************
setup i/p streams
******************************************/
in = new DataInputStream(client.getInputStream());
String line = in.readUTF();
while (!line.equals("STOP")) {
msg = msg + "\n Client : " + line;
handler.post(new Runnable() {
#Override
public void run() {
chat.setText(msg);
}
});
}
in.close();
client.close();
}
} catch (Exception e) {
}
}
}
}
//#Client Side Java File
package reciever;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.*;
import java.net.*;
import inc.teckzy.wif_chat.R;
public class ClientSide extends AppCompatActivity {
EditText serverIp,smessage;
TextView chat;
String serverIpAddress = "",msg = "",str;
Handler handler = new Handler();
Button sent,connectPhones;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_client_side);
chat = (TextView) findViewById(R.id.chat);
serverIp = (EditText) findViewById(R.id.server_ip);
smessage = (EditText) findViewById(R.id.smessage);
sent = (Button) findViewById(R.id.sent_button);
connectPhones = (Button) findViewById(R.id.connect_phones);
//-----------------------Connecting to IP------------------------------//
connectPhones.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
serverIpAddress = serverIp.getText().toString();
if (!serverIpAddress.equals(""))
{
Thread clientThread = new Thread(new
ClientThread());
clientThread.start();
}
}
});
//-------------------------------Initializing sent thread----------------//
sent.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
Thread sentThread = new Thread(new sentMessage());
sentThread.start();
}
});
}
class sentMessage implements Runnable
{
#Override
public void run()
{
try
{
InetAddress serverAddr =
InetAddress.getByName(serverIpAddress);
Socket socket = new Socket(serverAddr, 6666); //
DataOutputStream os = new DataOutputStream(socket.getOutputStream());
str = smessage.getText().toString();
str = str + "\n";
msg = msg + "Client : " + str;
handler.post(new Runnable() {
#Override
public void run() {
chat.setText(msg);
}
});
os.writeUTF(str);
os.flush();
os.close();
socket.close();
}
catch(IOException e)
{
}
}
}
public class ClientThread implements Runnable
{
InetAddress serverAddr;
public void run()
{
try
{
while(true)
{
serverAddr = InetAddress.getByName(serverIpAddress);
Socket socket = new Socket(serverAddr, 6666);
/*******************************************
setup i/p streams
******************************************/
DataInputStream in = new
DataInputStream(socket.getInputStream());
String line = in.readUTF();
while (!line.equals("Stop"))
{
msg = msg + "Server : " + line + "\n";
handler.post(new Runnable()
{
#Override
public void run()
{
chat.setText(msg);
}
});
}
in.close();
socket.close();
Thread.sleep(100);
}
}
catch (Exception e)
{}
}
}
}
You are using client = serverSocket.accept(); in server side every time you need to send a message.
And in client side you are trying to create a new Socket connection using new Socket
(serverAddr, 6666); multiple times.
Maintain a single Socket connection and single data input/output stream(do not create multiple instances) and you will be good to go.
See example at:
https://github.com/nabinbhandari/android-socket-messaging
I Solved it Just deleted the "sentMessage" Thread and implemented output stream in "sent.setOnClickListener(new View.OnClickListener()" in both Activity also did some modifications..Here is the working code Activity ...Hope this will help someone
#Server Activity
package inc.teckzy.wifi_chat;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.text.format.Formatter;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class Helper extends AppCompatActivity {
EditText smessage;
TextView chat,display_status;
String str,Smsg,Cmsg="";
int serverport = 6666;
ServerSocket serverSocket;
Socket client;
Handler updateConversationHandler =new Handler();
WifiManager wmanager;
DataOutputStream out;
DataInputStream in;
Button button_sent;
StringWriter errors = new StringWriter();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_helper);
wmanager = (WifiManager) getSystemService(WIFI_SERVICE);
#SuppressWarnings("deprecation")
String ip = Formatter.formatIpAddress(wmanager.getConnectionInfo().getIpAddress());
smessage = (EditText) findViewById(R.id.smessage);
chat = (TextView) findViewById(R.id.chat);
display_status = (TextView) findViewById(R.id.display_status);
Thread serverThread = new Thread(new serverThread());
serverThread.start();
display_status.setText("Hosted on: " + ip);
button_sent = (Button) findViewById(R.id.button_sent);
button_sent.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
try {
out = new DataOutputStream(client.getOutputStream());
str = smessage.getText().toString();
Smsg = "Server:" + str;
updateConversationHandler.post(new updateUIThread(Smsg));
out.writeUTF(str);
out.flush();
}catch (Exception e) {
e.printStackTrace(new PrintWriter(errors));
updateConversationHandler.post(new updateUIThread(errors.toString()));
}
smessage.getText().clear();
}
});
}
public class serverThread implements Runnable {
#Override
public void run() {
try {
serverSocket = new ServerSocket(serverport);
while (true) {
client = serverSocket.accept();
updateConversationHandler.post(new updateUIThread("Connected"));
/*******************************************
setup i/p streams
******************************************/
in = new DataInputStream(client.getInputStream());
String line = "";
while (!line.equals("STOP")) {
line=in.readUTF();
Cmsg ="Client: "+ line;
updateConversationHandler.post(new updateUIThread(Cmsg));
}
in.close();
client.close();
}
} catch (Exception e) {
e.printStackTrace(new PrintWriter(errors));
updateConversationHandler.post(new updateUIThread(errors.toString()));
}
}
}
class updateUIThread implements Runnable {
private String msg;
updateUIThread(String str) {
this.msg = str;
}
#Override
public void run() {
chat.setText(chat.getText().toString()+ msg + "\n");
}
}
#Override
protected void onStop() {
super.onStop();
try {
// MAKE SURE YOU CLOSE THE SOCKET UPON EXITING
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
And
#Client Activity
package inc.teckzy.wifi_chat.reciever;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.text.format.Formatter;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.InetAddress;
import java.net.Socket;
import inc.teckzy.wifi_chat.R;
public class ClientSide extends AppCompatActivity {
EditText serverIp,smessage;
TextView chat;
String serverIpAddress = "",Smsg,Cmsg = "",str;
Handler updateConversationHandler = new Handler();
Button sent,connectPhones;
Socket socket;
DataInputStream in;
DataOutputStream out;
StringWriter errors = new StringWriter();
WifiManager wmanager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_client_side);
chat = (TextView) findViewById(R.id.chat);
serverIp = (EditText) findViewById(R.id.server_ip);
wmanager = (WifiManager) getSystemService(WIFI_SERVICE);
smessage = (EditText) findViewById(R.id.smessage);
sent = (Button) findViewById(R.id.sent_button);
connectPhones = (Button) findViewById(R.id.connect_phones);
//-----------------------Connecting to IP------------------------------//
connectPhones.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
serverIpAddress = serverIp.getText().toString();
if (!serverIpAddress.equals(""))
{
Thread clientThread = new Thread(new
ClientThread());
clientThread.start();
}
}
});
//-------------------------------Initializing sent thread----------------//
sent.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
try {
out = new DataOutputStream(socket.getOutputStream());
str = smessage.getText().toString();
Cmsg = "Client: " + str;
updateConversationHandler.post(new updateUIThread(Cmsg));
out.writeUTF(str);
out.flush();
}catch(Exception e){
e.printStackTrace(new PrintWriter(errors));
updateConversationHandler.post(new updateUIThread(errors.toString()));}
smessage.getText().clear();
}
});
}
public class ClientThread implements Runnable
{
InetAddress serverAddr;
public void run()
{
try
{
serverAddr = InetAddress.getByName(serverIpAddress);
socket = new Socket(serverAddr, 6666);
updateConversationHandler.post(new updateUIThread("Connected"));
String ip = socket.getRemoteSocketAddress().toString();
updateConversationHandler.post(new updateUIThread(ip));
out = new DataOutputStream(socket.getOutputStream());
in = new DataInputStream(socket.getInputStream());
/*******************************************
setup i/p streams
******************************************/
String line = "";
while (!line.equals("Stop")) {
line=in.readUTF();
Smsg ="Server: " + line + "\n";
updateConversationHandler.post(new updateUIThread(Smsg));
}
out.close();
in.close();
socket.close();
}
catch (IOException e)
{updateConversationHandler.post(new updateUIThread("IO Error"));}
}
}
class updateUIThread implements Runnable {
private String msg;
updateUIThread(String str) {
this.msg = str;
}
#Override
public void run() {
chat.setText(chat.getText().toString()+ msg + "\n");
}
}
#Override
protected void onStop() {
super.onStop();
try {
// MAKE SURE YOU CLOSE THE SOCKET UPON EXITING
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
I am trying to send a simple message over TCP from my android phone (using java application) to my computer. I have an socket that is listening on my computer but as soon as I run this app, it crashes. I am really new to Android developing so please bear with me...
Here is my Java code:
package com.scorekeep.clienttcp;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity {
EditText textOut;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Socket socket = null;
try {
socket = new Socket("10.0.0.10",5000);
DataOutputStream DOS = new DataOutputStream(socket.getOutputStream());
DOS.writeUTF("HELLO_WORLD");
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
As requested an extended example :
import android.app.*;
import android.os.*;
import android.util.*;
import java.io.*;
import java.net.*;
public class MainActivity extends Activity
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new connection().execute();
}
}
class connection extends AsyncTask<String,String,String> {
public static PrintWriter out;
BufferedReader in;
public static boolean running = true;
#Override
protected String doInBackground(String... message) {
try
{
InetAddress serverAddr = InetAddress.getByName("localhost");
Socket socket = new Socket(serverAddr, 8008);
// send the message to the server
out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
in = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
while(running) {
String msgfromserver = in.readLine();
}
}
catch (Exception e)
{}
return null;
}
public static void sendmsg(String msg){
if(out!=null){
out.println(msg);
out.flush();
}
}
}
Usage:
Call connection.sendmsg("some text"); from OnClick method of button
And set connection.running = false; onbackpress. (Or before finishing activity)
You cannot execute background tasks like socket connection in ui thread. You should use AsyncTask.
Example
import android.app.*;
import android.os.*;
import android.util.*;
import java.io.*;
import java.net.*;
public class MainActivity extends Activity
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new connection().execute();
}
}
class connection extends AsyncTask<String,String,String> {
#Override
protected String doInBackground(String... message) {
try
{
InetAddress serverAddr = InetAddress.getByName("ip here");
Socket socket = new Socket(serverAddr, 5000); //port here
// send the message to the server
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
out.println("hi");
out.flush(); //optional
socket.close();
}
catch (Exception e)
{}
return null;
}
}
Note Untested. May contain errors.
Two changes in code. public static void sendmsg and public public static PrintWriter out at begining of AsyncTask class
I am fairly new to Android, i want to write a telnet client app for my Android. I have written the code using Apache commons library for telnet. Now i am able to connect to telnet server (for that i have used Asyctask concept) and able to read login banner after a long time i don't know what is causing that. I have modified the example given in Apache commons to work with my android code.I have two java codes in my "src" folder (MainActivity.java and TelnetClientExample.java). First, i want to get the login prompt and then i want user to interact with it please help, Thanks in advance :)
I am posting my screen capture of what i am getting.
MainActivity.java
package com.example.telnetapp;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.PrintWriter;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity{
public static int port_int_address;
private EditText server,port;
private Button connect;
public static String ip,port_address;
public PrintWriter out;
public static TextView textResponse;
static String response;
public InputStream instr;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
server = (EditText)findViewById(R.id.edittext1);
port = (EditText)findViewById(R.id.edittext2);
connect = (Button)findViewById(R.id.connect);
textResponse = (TextView)findViewById(R.id.response);
connect.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
ip = server.getText().toString();
port_address = port.getText().toString();
port_int_address = Integer.parseInt(port_address);
try{
MyClientTask task = new MyClientTask(ip, port_int_address);
task.execute();
}
catch(Exception e){Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_LONG).show();}
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public class MyClientTask extends AsyncTask<Void, Void, Void> {
String dstAddress;
int dstPort;
TelnetClientExample job;
MyClientTask(String inetAddress, int port){
dstAddress = inetAddress;
dstPort = port;
}
#Override
protected Void doInBackground(Void... arg0) {
try {
job = new TelnetClientExample();
job.backgroundjob();
}
catch (Exception e)
{
Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_SHORT).show();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
try {
instr = TelnetClientExample.tc.getInputStream();
byte[] buff = new byte[1024];
int ret_read = 0;
do
{
ret_read = instr.read(buff);
if(ret_read > 0)
{
MainActivity.response += new String(buff, 0, ret_read);
}
}
while (ret_read >= 0);
}
catch (Exception e) {
MainActivity.response += e.toString();
MainActivity.response += "From reading from telnet server ! \n";
}
textResponse.setText(response);
super.onPostExecute(result);
}
}
}
TelnetClientExample.java
package com.example.telnetapp;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.net.telnet.TelnetClient;
public class TelnetClientExample {
public String remoteip = MainActivity.ip;
public int remoteport= MainActivity.port_int_address;
public static TelnetClient tc = null;
public void backgroundjob() throws IOException {
tc = new TelnetClient();
try {
tc.connect(remoteip, remoteport);
}
catch (Exception e) {
}
}
public void close_con(){
try {
tc.disconnect();
}
catch (Exception e) {
MainActivity.response += e.toString();
MainActivity.response += "From reading from disconnecting telnet server ! \n";
}
}
}
The problem is in this code snippet . please look into this and help me to get an interactive session.
protected void onPostExecute(Void result) {
try {
instr = TelnetClientExample.tc.getInputStream();
byte[] buff = new byte[1024];
int ret_read = 0;
do
{
ret_read = instr.read(buff);
if(ret_read > 0)
{
MainActivity.response += new String(buff, 0, ret_read);
}
}
while (ret_read >= 0);
}
catch (Exception e) {
MainActivity.response += e.toString();
MainActivity.response += "From reading from telnet server ! \n";
}
textResponse.setText(response);
super.onPostExecute(result);
}
The problem i am getting -
I have an Android app, which should receive and read NMEA-sentences
e.g. $GPGLL,3751.65,S,14507.36,E*77
from a remote TCP-Server using Telnet protocol. I am using the org.apache.commons.net.telnet.TelnetClient library.
What works:
Connecting to Server
Reading some sentences without any error
Problem:
There are more than half of the sentences missing. I guess that it is a timing problem, perhaps this has also to do with the connection which gets restarted in every iteration.
Here is my MainActivity.java:
package com.example.clienttel;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import org.apache.commons.net.telnet.TelnetClient;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Go to ClientThread, where NMEA-sentences will be received
int i;
for (i = 0; i < 10000; i++) // 10000 for testing
new Thread(new ClientThread()).start();
}
class ClientThread implements Runnable {
//#Override
public void run() {
TelnetClient telnet = new TelnetClient();
// Variables
String ADDRESS = "194.66.82.11";
int PORT = 51000;
String NMEA = null;
final String TAG = "TestApp";
// Connect To Server
try {
telnet.connect(ADDRESS, PORT);
} catch (IOException e) {
e.printStackTrace();
}
// Process NMEA-sentences
InputStream inStream = telnet.getInputStream();
BufferedReader r = new BufferedReader(new InputStreamReader(inStream));
try {
NMEA = r.readLine();
} catch (IOException e) {
e.printStackTrace();
}
// Ignore "...busy" sentences
if (NMEA != null) {
if(!(NMEA.equals("*** Serial port is busy ***"))) {
Log.i(TAG, NMEA);
}
}
// Disconnect From Server
try {
telnet.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Any help would be appreciated!
EDIT:
My code now looks like this:
package com.example.clienttel;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import org.apache.commons.net.telnet.TelnetClient;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
public class MainActivity extends ActionBarActivity {
// Variables
public String ADDRESS = "194.66.82.11";
public int PORT = 50100;
public String NMEA = null;
public final String TAG = "TestApp";
public boolean first = true;
// Handler in mainthread
Handler handler = new Handler() {
public void handleMessage(Message msg) {
String dataString = "";
Bundle bundle = msg.getData();
Log.d("handleMessage", bundle.toString());
if (bundle.containsKey("outgoingString")) {
dataString = bundle.getString("outgoingString");
}
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ClientThread ct;
ct = new ClientThread();
ct.mhandler=handler;
int i;
for (i = 0; i < 10000; i++) { // 10000 for testing
// Go to ClientThread, where NMEA-sentences will be received
//new Thread(new ClientThread()).start();
ct.start();
}
}
class ClientThread implements Runnable {
public Handler mhandler = null;
#Override
public void run() {
TelnetClient telnet = new TelnetClient();
if (first) {
// Connect To Server in 1st Iteration
try {
telnet.connect(ADDRESS, PORT);
} catch (IOException e) {
e.printStackTrace();
}
first = false;
}
// Process NMEA-sentences
InputStream inStream = telnet.getInputStream();
BufferedReader r = new BufferedReader(new InputStreamReader(inStream));
try {
NMEA = r.readLine();
} catch (IOException e) {
e.printStackTrace();
}
// Handler in ClientThread to send back
Bundle b = new Bundle();
b.putString("outgoingString", NMEA);
Message m = mhandler.obtainMessage();
m.setData(b);
mhandler.sendMessage(m);
}
}
}
but I am not sure about the placement of the handlers
As #EJP said, opening an closing the connection for each line will kill the app...
A better approach is have the thread handle the communication(s) and wait for the next line, passing the data back to the main thread as a bundle message.
There are plenty of examples out there, but essentially you create a handler in your main thread:
Handler handler = new Handler()
{
public void handleMessage(Message msg)
{
String dataString = "";
Bundle bundle = msg.getData();
Log.d("handleMessage", bundle.toString());
if (bundle.containsKey("outgoingString"))
{
dataString = bundle.getString("outgoingString");
}
// you can handle other message types here....
}
and pass it (the handler) to your ClientThread (here, as mhandler) where you can send the messages back:
Bundle b = new Bundle();
b.putString("outgoingString", outgoingText);
Message m = mhandler.obtainMessage();
m.setData(b);
mhandler.sendMessage(m);