I want to write a simple android app that sends text to python server and then puts its answer (in our case: how many vowels in the data) and use Logcat to see it really got the data.
Everything works just fine excepts for the part where the clients waits for the server response.
It just getting stuck there even though the server says it sent the data back to the client.
Does anyone have an idea what might have caused this problem?
UPDATE:
After sniffing with Wireshark I saw that the data the client and server sends to each other is "Malformed packet". Anyone knows why?
my client code:
public class MainActivity extends Activity {
private Socket socket;
private static final int SERVERPORT = 5000;
private static final String SERVER_IP = "10.0.0.1";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread(new ClientThread()).start();
}
public void onClick(View view) {
try {
EditText et = (EditText) findViewById(R.id.EditText01);
String str = et.getText().toString();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
out.println(str);
Log.i("Tag","sent " + str);
BufferedReader input = new BufferedReader(new InputStreamReader(this.socket.getInputStream()));
try {
String read = input.readLine();
Log.i("Tag","got " + read);
} catch (IOException e) {
e.printStackTrace();
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
class ClientThread implements Runnable {
#Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
my server code:
import socket
srv_sock = socket.socket()
ip = "0.0.0.0" # means local
port = 3001 # 0 means get random free port
srv_sock.bind((ip, port))
srv_sock.listen(5)
while True:
(new_sock, address) = srv_sock.accept()
print "Hello! this is a vowels server! You need to send a word or a
sentence and I'll give you the number of vowels in it!"
while True:
data = new_sock.recv(1024)
if data == "" :
print "Client Disconnected"
break
print "Received<<< " + data
data = data.upper()
to_send = "Num of vowels is "
cnt=0
if data.isdigit():
to_send = "ERROR:Number doesn't have any vowels!"
else:
for letter in data:
if (letter == 'A' or letter == 'E' or letter == 'O' or letter
== 'U' or letter == 'I'):
cnt += 1
to_send += str(cnt)
new_sock.send(unicode(to_send + "\n"))
print "Sent >>>" + to_send
new_sock.close()
srv_sock.close()
Related
I have writing some driven tests to a flutter project and there are a barcode scanner functionality which I can test successfully using the virtual scene tool provided by android emulator.
However there are many cases to test regarding to different barcodes. I want to set a specific barcode image on virtual scene to each case. Is it possible?
I found that the value of this image is putted on ~/.android/avd/[emulatorName]/AVD.conf file at virtualscene\posters variable.
virtualscene\posters=#Variant(\0\0\0\b\0\0\0\x2\0\0\0\b\0w\0\x61\0l\0l\0\0\0\n\xff\xff\xff\xff\0\0\0\n\0t\0\x61\0\x62\0l\0\x65\0\0\0\n\xff\xff\xff\xff)
virtualscene\posters=#Variant(\0\0\0\b\0\0\0\x2\0\0\0\b\0w\0\x61\0l\0l\0\0\0\n\ 0\0\0\\\0/\0U\0s\0\x65\0r\0s\0/\0l\0\x65\0o\0n\0\x61\0r\0\x64\0o\0.\0\x61\0r\0m\0\x65\0r\0o\0/\0\x44\0\x65\0s\0k\0t\0o\0p\0/\0J\0\x61\0m\0\x65\0s\0W\0i\0l\0s\0o\0n\0.\0p\0n\0g\0\0\0\n\0t\0\x61\0\x62\0l\0\x65\0\0\0\n\xff\xff\xff\xff)
You can replace the default (global) image located at $ANDROID_SDK_HOME/emulator/resources/poster.png with your poster.png image,
nor change the default pointer by editing the file $ANDROID_SDK_HOME/emulator/resources/Toren1BD.posters.
You can set the virtual scene image to a specified path. And manipulate the target image while testing.
As the Instrumented tests are running on your (virtual) device, it cannot manipulate the host machine files directly. What can be done, (which is an ugly hack) is to start a server on the host, which can be reached from the virtual device with the hosts loop-back "10.0.2.2" address.
This server can manipulate the target files.
If anybody has better solution, please share it!
An example server and client is here.
Server:
import java.io.*;
import java.net.*;
import java.nio.channels.FileChannel;
public class FileManipulatorServer {
public static void main(String args[]) {
int port = 6789;
FileManipulatorServer server = new FileManipulatorServer( port );
server.startServer();
}
// declare a server socket and a client socket for the server
private ServerSocket fileManipulatorServer = null;
private Socket clientSocket = null;
private int port;
public FileManipulatorServer(int port ) {
this.port = port;
}
public void stopServer() {
System.out.println( "Server cleaning up." );
System.exit(0);
}
public void startServer() {
// Try to open a server socket on the given port
// Note that we can't choose a port less than 1024 if we are not
// privileged users (root)
try {
fileManipulatorServer = new ServerSocket(port);
}
catch (IOException e) {
System.out.println(e);
}
System.out.println( "Waiting for connections. Only one connection is allowed." );
// Create a socket object from the ServerSocket to listen and accept connections.
// Use FileManipulatorTask to process the connection.
while ( true ) {
try {
clientSocket = fileManipulatorServer.accept();
FileManipulatorTask task = new FileManipulatorTask(clientSocket, this);
task.run();
}
catch (IOException e) {
System.out.println(e);
}
}
}
}
class FileManipulatorTask {
private BufferedReader is;
private PrintStream os;
private Socket clientSocket;
private FileManipulatorServer server;
public FileManipulatorTask(Socket clientSocket, FileManipulatorServer server) {
this.clientSocket = clientSocket;
this.server = server;
System.out.println( "Connection established with: " + clientSocket );
try {
is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
os = new PrintStream(clientSocket.getOutputStream());
} catch (IOException e) {
System.out.println(e);
}
}
public void run() {
String line;
try {
boolean serverStop = false;
line = is.readLine();
System.out.println( "Received " + line );
saveImageToPoster(line.trim());
os.println("OK");
os.flush();
System.out.println( "Connection closed." );
is.close();
os.close();
clientSocket.close();
if ( serverStop ) server.stopServer();
} catch (IOException e) {
System.out.println(e);
}
}
private void saveImageToPoster(String filename) {
try {
FileChannel src = new FileInputStream("C:\\fullpathtopostercandidates\\"+filename).getChannel();
FileChannel dest = new FileOutputStream("C:\\fullpathtoconfiguredposter\\poster.jpg").getChannel();
dest.transferFrom(src, 0, src.size());
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Client:
import java.io.*;
import java.net.*;
public class FileNameSenderClient {
private String hostname = "10.0.2.2";
private int port = 6789;
public void sendFileName(String filename) {
Socket clientSocket = null;
DataOutputStream os = null;
BufferedReader is = null;
try {
clientSocket = new Socket(hostname, port);
os = new DataOutputStream(clientSocket.getOutputStream());
is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
} catch (UnknownHostException e) {
System.err.println("Don't know about host: " + hostname);
} catch (IOException e) {
System.err.println("Couldn't get I/O for the connection to: " + hostname);
}
if (clientSocket == null || os == null || is == null) {
System.err.println( "Something is wrong. One variable is null." );
return;
}
try {
System.out.println("Write to output stream");
os.writeBytes( filename +"\n");
os.flush();
String responseLine = is.readLine();
System.out.println("Server returns: " + responseLine);
os.close();
is.close();
clientSocket.close();
} catch (UnknownHostException e) {
System.err.println("Trying to connect to unknown host: " + e);
} catch (IOException e) {
System.err.println("IOException: " + e);
}
}
}
Use the FileNameSenderClient from your instrumented test like this.
#Test
public void testQRcodeReadingOK()
{
FileNameSenderClient c = new FileNameSenderClient();
c.sendFileName("QRCode.jpg");
//your code that wants to use the image, like the this:
onView(withId(R.id.load_qr_code)).perform(click());
}
Ive been trying to setup a server using ESP8266 wifi module on a particular port. I'm done with that.
I want to receive the message from it now.
Whenever I connect using socket.connect(), I am able to detect it in the esp8266. But I cant receive any message, the server sends through the same socket.
I am trying to obtain the message using DataInputStream inside a while loop continuously in a async task.Pls let me know if my approach or code is wrong! Thanks!
This is my code:
package test.espclient;
import java.io.DataInputStream;
//import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
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 {
TextView textResponse;
EditText editTextAddress, editTextPort;
Button buttonConnect, buttonClear,buttonDiscon , buttonSendMsg;
EditText welcomeMsg;
Socket socket;
boolean socketStatus = false;
MyClientTask myClientTask;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editTextAddress = (EditText) findViewById(R.id.address);
editTextPort = (EditText) findViewById(R.id.port);
buttonConnect = (Button) findViewById(R.id.connect);
buttonClear = (Button) findViewById(R.id.clear);
buttonDiscon = (Button) findViewById(R.id.closeSocket);
buttonSendMsg = (Button) findViewById(R.id.sendMsg);
textResponse = (TextView) findViewById(R.id.response);
welcomeMsg = (EditText)findViewById(R.id.welcomemsg);
buttonConnect.setOnClickListener(buttonConnectOnClickListener);
buttonDiscon.setOnClickListener(buttonDisconnectOnCLickListener);
//buttonSendMsg.setOnClickListener(sendMessage);
buttonClear.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
textResponse.setText("");
}
});
}
OnClickListener buttonConnectOnClickListener = new OnClickListener() {
#Override
public void onClick(View arg0) {
if(socketStatus)
Toast.makeText(MainActivity.this,"Already talking to a Socket!! Disconnect and try again!", Toast.LENGTH_LONG).show();
else {
socket = null;
String address = editTextAddress.getText().toString();
int port = Integer.parseInt(editTextPort.getText().toString());
String tMsg = welcomeMsg.getText().toString();
if (address == null || port == 0)
Toast.makeText(MainActivity.this, "Please enter valid address/port", Toast.LENGTH_LONG).show();
else {
myClientTask = new MyClientTask(address,port,tMsg);
myClientTask.execute();
} //else when no active socket conn. and credentials are validated.
} //else when already active socket conn.
}
};
OnClickListener buttonDisconnectOnCLickListener = new OnClickListener() {
#Override
public void onClick(View v) {
if (!socketStatus)
Toast.makeText(MainActivity.this, "SOCKET Already Closed!!", Toast.LENGTH_SHORT).show();
else {
try {
onDisconnect();
if(myClientTask.isCancelled()) {
socket.close();
Toast.makeText(MainActivity.this, "Socket Closed!", Toast.LENGTH_SHORT).show();
socketStatus = false;
}
else
{
Toast.makeText(MainActivity.this, "Couldn't Disconnect! Pls try again!", Toast.LENGTH_SHORT).show();
socketStatus = true;
}
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(MainActivity.this,e.toString(), Toast.LENGTH_SHORT).show();
}
}
}
};
// OnClickListener sendMessage = new OnClickListener() {
// #Override
// public void onClick(View v) {
// String msg = welcomeMsg.toString();
// if(msg.equals(""))
// {
// Toast.makeText(MainActivity.this, "Message is empty!!!", Toast.LENGTH_SHORT).show();
// }
// else if(!socketStatus)
// {
// Toast.makeText(MainActivity.this, "Please Establish Socket Connection first!", Toast.LENGTH_SHORT).show();
// }
// else
// {
// MyClientTask myClientTask = new MyClientTask(editTextAddress
// .getText().toString(), Integer.parseInt(editTextPort
// .getText().toString()),
// msg);
// myClientTask.execute();
//
// }
//
// }
// };
public void onDisconnect()
{
myClientTask.cancel(true);
}
public class MyClientTask extends AsyncTask<Void, String, Void> {
String dstAddress;
int dstPort;
String response ="";
String msgToServer;
MyClientTask(String addr, int port, String msgTo) {
dstAddress = addr;
dstPort = port;
msgToServer = msgTo;
Log.w("MSG","Entering async task");
}
#Override
protected Void doInBackground(Void... arg0) {
// DataOutputStream dataOutputStream = null;
DataInputStream dataInputStream = null;
try {
socket = new Socket(dstAddress, dstPort);
socketStatus = true;
// dataOutputStream = new DataOutputStream(socket.getOutputStream());
// if(msgToServer != null){
// dataOutputStream.writeUTF(msgToServer);
// }
}
catch (UnknownHostException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
response = "UnknownHostException: " + e.toString();
socketStatus = false;
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "IOException: " + e.toString();
}
Log.w("MSG","Inside while loop for retrieving data");
while(!isCancelled()){
try {
dataInputStream = new DataInputStream(socket.getInputStream());
response = dataInputStream.readUTF();
if(!response.isEmpty())
{
publishProgress(response);
Log.w("Data:",response);
}
} catch (IOException e) {
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) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
try {
Log.w("MSG","Stopping async task");
socket.close();
socketStatus = false;
} catch (IOException e) {
e.printStackTrace();
socketStatus = true;
}
return null;
}
#Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
textResponse.setText(values[0]);
Toast.makeText(MainActivity.this,"Server:"+values[0],Toast.LENGTH_LONG).show();
Log.w("MSG","Updating with msg");
}
#Override
protected void onPostExecute(Void result) {
Log.w("MSG","On postExecute method..");
textResponse.setText(response);
super.onPostExecute(result);
}
}
}
UPDATE(16-12-15) I made the following changes under the doInBackground().
originally, I used DataInputStream, now I replaced it with BufferedReader.
The change was made under the while loop part for constantly checking the socket input stream. Also added the ESP8266 code for reference.
Now I able to Receive the text sent from ESP8266, but it reaches only after I send 3 or 4 messages via CIPSEND cmd. for e.g. if i send "hi", "hello" "yo", after sending the third word, I receive all the words together as "hihelloyo"
Instead of recieving each message as soon as it is sent, I receive it very late.
I am not sure what exactly is causing this problem. May be the buffer size?
How to solve this ?
MODIFIED CODE:
protected Void doInBackground(Void... arg0) {
// DataOutputStream dataOutputStream = null;
// DataInputStream dataInputStream = null;
try {
socket = new Socket(dstAddress, dstPort);
socketStatus = true;
// dataOutputStream = new DataOutputStream(socket.getOutputStream());
// if(msgToServer != null){
// dataOutputStream.writeUTF(msgToServer);
// }
}
catch (UnknownHostException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
response = "UnknownHostException: " + e.toString();
socketStatus = false;
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "IOException: " + e.toString();
}
Log.w("MSG","Inside while loop for retrieving data");
while(!isCancelled() && socketStatus) {
try {
// dataInputStream = new DataInputStream(socket.getInputStream());
// response = dataInputStream.readUTF();
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
response = br.readLine();
if (!response.isEmpty()) {
publishProgress(response);
Log.w("Data:", response);
}
} catch (IOException e) {
e.printStackTrace();
}
}
ESP266 code
#include <AltSoftSerial.h>
AltSoftSerial ESP8266 ;//(8,9)|Rx,Tx
int LED = 13;
boolean FAIL_8266 = false;
#define BUFFER_SIZE 128
char buffer[BUFFER_SIZE];
String ssid="\"SSID\"";
String pass="\"PASSWORD\"";
void clearESP8266SerialBuffer()
{
Serial.println("= clearESP8266SerialBuffer() =");
while (ESP8266.available() > 0) {
char a = ESP8266.read();
Serial.write(a);
}
Serial.println("==============================");
}
void sendHTTPResponse(int id, String content)
{
String response;
response = "HTTP/1.1 200 OK\r\n";
response += "Content-Type: text/html; charset=UTF-8\r\n";
response += "Content-Length: ";
response += content.length();
response += "\r\n";
response +="Connection: close\r\n\r\n";
response += content;
String cmd = "AT+CIPSEND=";
cmd += id;
cmd += ",";
cmd += response.length();
Serial.println("--- AT+CIPSEND ---");
sendESP8266Cmdln(cmd, 1000);
Serial.println("--- data ---");
sendESP8266Data(response, 1000);
}
boolean waitOKfromESP8266(int timeout)
{
do{
Serial.println("wait OK...");
delay(1000);
if(ESP8266.find("OK"))
{
return true;
}
}while((timeout--)>0);
return false;
}
//Send command to ESP8266, assume OK, no error check
//wait some time and display respond
void sendESP8266Cmdln(String cmd, int waitTime)
{
ESP8266.println(cmd);
delay(waitTime);
clearESP8266SerialBuffer();
}
//Basically same as sendESP8266Cmdln()
//But call ESP8266.print() instead of call ESP8266.println()
void sendESP8266Data(String data, int waitTime)
{
ESP8266.print(data);
delay(waitTime);
clearESP8266SerialBuffer();
}
void adc()
{
int ldr;
for(int i=0;i<=3;i++)
{
ldr = analogRead(A0);
sendESP8266Cmdln("AT+CIPSEND=0,5",1000);
sendESP8266Cmdln(String(ldr),1000);
delay(1000);
}
}
void setup()
{
Serial.begin(9600);
ESP8266.begin(9600);
pinMode(LED,OUTPUT);
do{
ESP8266.println("AT+RST");
delay(1000);
if(ESP8266.find("Ready"))
{
Serial.println("Module is ready");
delay(1000);
clearESP8266SerialBuffer();
sendESP8266Cmdln("AT+CWMODE=1",1000);
//Join Wifi network
sendESP8266Cmdln("AT+CWJAP="+ssid+","+pass,6500);
//Get and display my IP
sendESP8266Cmdln("AT+CIFSR", 1000);
//Set multi connections
sendESP8266Cmdln("AT+CIPMUX=1", 1000);
//Setup web server on port 80
sendESP8266Cmdln("AT+CIPSERVER=1,3333",1000);
Serial.println("Server setup finish");
FAIL_8266 = false;
}else{
Serial.println("Module have no response.");
delay(500);
FAIL_8266 = true;
}
}while(FAIL_8266);
digitalWrite(LED, HIGH);
ESP8266.setTimeout(1000);
}
void loop() {
// listen for communication from the ESP8266 and then write it to the serial monitor
if(ESP8266.available()) // check if the esp is sending a message
{
String msg = ESP8266.readString();
if(msg.substring(0,4)=="Link")
Serial.println("Client connected!");
else if(msg.substring(0,6)=="Unlink")
Serial.println("Client Disconncected!!");
else if(msg.substring(1,5)=="+IP")
{
Serial.println("Client says: "+msg.substring(9,14));
}
else
{
// Serial.println("Calling ADC.!");
//adc();
// Serial.println("Msg:"+msg.charAt(0)+msg.charAt(1)+msg.charAt(2)+msg.charAt(3));
// Serial.println("Something recieved!: "+msg.substring(1,2));
Serial.println("MSG:"+msg);
}
}
// listen for user input and send it to the ESP8266
if ( Serial.available() ) { ESP8266.write( Serial.read() ); }
}
//Clear and display Serial Buffer for ESP8266
UPDATE(17-12-15):Added pics for reference
My arduino serial window showing the AT+CIPSEND commands.
pic of the app running on phone.
As to this comment:
... it worked! I can get the messages immediately irrespective of their lengths, after i close the connection on esp side using cipclose=0. But is this is the only way? Is it possible to make the device and the app talk? How come it is possible in the telnet application, where i can continuously send data till i close connection on one side.?
On the upper application layers data from TCPIP connection is presented as a Stream. Using this stream with well-defined application protocols like HTTP or telnet, message exchange is defined. In your case basically Android side does not know what amount of data to receive. After using buffered reader you get buffered answer, not the whole.
In telnet protocol for example there are control commands. Thus the system goes on working.
To solve your case:
Close connection after every message. (this slows down things)
Implement a basic application protocol. For example: Implement a Message frame:
FRAME
1st byte : length ( this byte gives the length of the payload )
2nd...255th byte : payload ( this is the actual message )
LOGIC
-Sender packs the frame giving length and payload.
-Sender sends the data
...
-Receiver queries for the available bytes.
-When available bytes are >1 receive only 1 byte say it is 'n'
-'n' is the length of the total frame
-Read 'n' bytes from the stream. if EOF then return what is received.
In addition to this you can implement control commands.
For example you may want the receiver to close the connection so your frame can be:
Byte 1 : length
Byte 2 : command (0=nothing, 1=close conn)
Byte 3..n : payload
LOGIC
-When receiver finished receiving and command is 1 then closes the connection.
i've created an android application in which, android application act as the client, and server resides in the desktop application.
suppose there are 10 android application runs the same at a time on 10 different android tablets, when one updation received from one tablet, the desktop application sends the updation to all other remaining tablets. how could the server knows how many clients are connected and how to send the message to all the clients
what i plan is to run a server in all android so that when one updation received from one tablet, the desktop application sends the updation to all other remaining tablets.
can anyone please tell me some suggestion regarding this.
Client side
private int SERVER_PORT = 9999;
class Client implements Runnable {
private Socket client;
private PrintWriter out;
private Scanner in;
#Override
public void run() {
try {
client = new Socket("localhost", SERVER_PORT);
Log.d("Client", "Connected to server at port " + SERVER_PORT);
out = new PrintWriter(client.getOutputStream());
in = new Scanner(client.getInputStream());
String line;
while ((line = in.nextLine()) != null) {
Log.d("Client", "Server says: " + line);
if (line.equals("Hello client")) {
out.println("Reply");
out.flush();
}
}
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Server class
class ServerThread implements Runnable {
private ServerSocket server;
#Override
public void run() {
try {
server = new ServerSocket(SERVER_PORT);
Log.d("Server", "Start the server at port " + SERVER_PORT
+ " and waiting for clients...");
while (true) {
Socket socket = server.accept();
Log.d("Server",
"Accept socket connection: "
+ socket.getLocalAddress());
new Thread(new ClientHandler(socket)).start();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
class ClientHandler implements Runnable {
private Socket clientSocket;
private PrintWriter out;
private Scanner in;
public ClientHandler(Socket clietSocket) {
this.clientSocket = clietSocket;
}
#Override
public void run() {
try {
out = new PrintWriter(clientSocket.getOutputStream());
in = new Scanner(clientSocket.getInputStream());
String line;
Log.d("ClientHandlerThread", "Start communication with : "
+ clientSocket.getLocalAddress());
out.println("Hello client");
out.flush();
while ((line = in.nextLine()) != null) {
Log.d("ClientHandlerThread", "Client says: " + line);
if (line.equals("Reply")){
out.print("Server replies");
out.flush();
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
You could save the Sockets in a List and send a message through all the OutputStreams in that List:
Socket socket = Server.accept();
sockets.add(socket); //sockets is an ArrayList<Socket>
public void sendMessageToEveryone(String msg) {
for(Socket s : sockets) {
s.getOutputStream().write(msg.getBytes());
s.getOutputStream().flush();
}
You could use the Google Cloud Messaging service.
Take a look at this page:
https://developer.android.com/google/gcm/index.html
I have a TCP Client in Android (Java program in Eclipse). The server was another Java app running in Eclipse. Everything works fine in this situation.
When I tried to receive message from my colleague's app (developed in Rhapsody and I think C++), I receive the message only after his app is closed and not while his app is running and sending messages. Do you have any idea why this happens?
Thank you for the time and effort on this.
Cheers,
Madhu
The java server is like this:
public class TCPSendServer implements Runnable{
public static final String SERVERIP = "192.168.178.24";
public static final int SERVERPORT = 1200;
//static Category cat = Category.getInstance(TCPSendServer.class.getName());
//cat.debug("Start of main()");
public void run() {
try {
System.out.println("S: Connecting...");
ServerSocket serverSocket = new ServerSocket(SERVERPORT);
String msg = "<MSG><N>shiftDirection</N><V>1</V></MSG>";
String msg1 = "<MSG><N>vehicleSpeed</N><V>120</V></MSG>";
String msg2 = "SD<!N><V>0<!V><!MSG>";
//while (true) {
Socket client = serverSocket.accept();
try {
System.out.println("S: Sending: '" + msg + "'");
PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(client.getOutputStream())),true);
Thread.sleep (5000);
out.println(msg);
Thread.sleep (5000);
//out.println(msg2);
Thread.sleep (5000);
out.println(msg1);
//out.flush();
System.out.println("S: Sent.");
System.out.println("S: Done.");
} catch(Exception e) {
System.out.println("S: Error");
e.printStackTrace();
} //finally {
// client.close();
//}
//}
} catch (Exception e) {
System.out.println("S: First try error");
e.printStackTrace();
}
}
public static void main (String a[]) {
Thread desktopServerThread = new Thread(new TCPSendServer());
desktopServerThread.start();
}
}
The Android client code:
Main activity:
public class TCPListen extends Activity implements TCPListener {
private TextView mTitle;
public String data[] = new String[2];
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
// Set up the window layout
requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
setContentView(R.layout.main);
getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.custom_title);
// Set up the custom title
mTitle = (TextView) findViewById(R.id.title_left_text);
mTitle.setText(R.string.app_name);
mTitle = (TextView) findViewById(R.id.title_right_text);
//TcpServiceHandler handler=new TcpServiceHandler(this);
//handler.execute("192.168.178.24");
TcpServiceHandler handler = new TcpServiceHandler(this,this);
Thread th = new Thread(handler);
th.start();
}
public String[] callCompleted(String source){
Log.d("TCP", "Std parser " + source);
mTitle.setText(source);
//String data[] = new String[2];
//if (source.matches("<MSG><N>.*</N><V>.*</V></MSG>")) {
Document doc = null;
try{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = (Document) db.parse(new ByteArrayInputStream(source.getBytes()));
NodeList n = doc.getElementsByTagName("N");
Node nd = n.item(0);
String msgName = nd.getFirstChild().getNodeValue();
NodeList n1 = doc.getElementsByTagName("V");
Node nd1 = n1.item(0);
String tmpVal = nd1.getFirstChild().getNodeValue();
data[0] = msgName;
data[1] = tmpVal;
Log.d("TCP", "Inside Std parser " + data[0] + " " + data[1]);
//actionOnData(data[0], data[1]);
}
catch(Exception e){
e.printStackTrace();
}
Log.d("TCP", "Just outside Std parser " + data[0] + " " + data[1]);
return data;
//} else Log.d("TCP", "Message in wrong format " + source);
//mTitle.setText("Message in wrong format " + source);
//return data;
}
Interface:
public interface TCPListener {
public String[] callCompleted(String msg);
}
TCPServiceHandler:
public class TcpServiceHandler implements Runnable {
TCPListener _listener;
private Activity _act;
public TcpServiceHandler(TCPListener listener, Activity act){
_listener = listener;
_act = act;
}
public synchronized void run() {
// TODO Auto-generated method stub
//if(socket==null){
try {
InetAddress serverAddr = InetAddress.getByName("192.168.178.25");
Socket socket = new Socket(serverAddr, 1200);
//
while(true){
try {
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
final String str = in.readLine();
this._act.runOnUiThread(new Runnable(){
public void run() {
_listener.callCompleted(str);
}
});
}
catch(Exception e){
e.printStackTrace();
}
}
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
This is problem with the SERVERIP here. Are you running your app from an emulator in your local machine? Your emulator is not part of your LAN. Emulator runs behind a virtual router/firewall service that isolates it from your development machine's network interfaces and settings and from the internet.
So you need to use network redirections or port forwarding to achieve communication with the server which is on a separate machine.
If you are running the app on a device then you can make that device as part of your network and then it should work.
There has been a solution, at least for the time being. I use readLine() to read contents of sockets and this expects \n or \r or similar characters until it returns the contents. This was not the issue for me when both server and client were in Java. But when the client had to receive messages from a different app, I faced this problem. It was overcome by just adding \n to the end of message sent by the other app.
I use the following code to receive the data from a particular port. It's not working in Android. But sending data to particular port is working fine.
public class UDPDemo extends Activity {
private TextView tv;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv = (TextView)findViewById(R.id.recv_message);
try {
DatagramSocket clientsocket=new DatagramSocket(9876);
byte[] receivedata = new byte[1024];
while(true)
{
DatagramPacket recv_packet = new DatagramPacket(receivedata, receivedata.length);
Log.d("UDP", "S: Receiving...");
clientsocket.receive(recv_packet);
String rec_str = new String(recv_packet.getData());
tv.setText(rec_str);
Log.d(" Received String ",rec_str);
InetAddress ipaddress = recv_packet.getAddress();
int port = recv_packet.getPort();
Log.d("IPAddress : ",ipaddress.toString());
Log.d(" Port : ",Integer.toString(port));
}
} catch (Exception e) {
Log.e("UDP", "S: Error", e);
}
}
}
If you are using the emulator you may need setup redirects, remember the emulator is behind a virtual router.
In other words, type these commands in;
telnet localhost 5554
redir add udp:9876:9876
and try again.
Used Port numbers
Create Datagram packet
try {
mDataGramSocket = new DatagramSocket(Config.PORT_NUMBER);
mDataGramSocket.setReuseAddress(true);
mDataGramSocket.setSoTimeout(1000);
} catch (SocketException e) {
e.printStackTrace();
}
Call below function through AsyncTask
Create Function to receive infinitely
public void receive() {
String text;
byte[] message = new byte[1500];
DatagramPacket p = new DatagramPacket(message, message.length);
try {
while (true) { // && counter < 100 TODO
// send to server omitted
try {
mDataGramSocket.receive(p);
text = new String(message, 0, p.getLength());
// If you're not using an infinite loop:
//mDataGramSocket.close();
} catch (SocketTimeoutException | NullPointerException e) {
// no response received after 1 second. continue sending
e.printStackTrace();
}
}
} catch (Exception e) {
e.printStackTrace();
// return "error:" + e.getMessage();
mReceiveTask.publish("error:" + e.getMessage());
}
// return "out";
}