Develop Reference

How to get client ip which is connected to android mobile hotspot in java scoket?

Is there any way to get client ip which is connected to android hotspot in java scoket, i have to send input values to client ip on submit
Here what i tried :
private class AttemptSubmit {
public ArrayList<String> getClientList1() {
ArrayList<String> clientList = new ArrayList<>();
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader("/proc/net/arp"));
String line;
while ((line = br.readLine()) != null) {
String[] clientInfo = line.split(" +");
String mac = clientInfo[3];
if (mac.matches("..:..:..:..:..:..")) {
clientList.add(clientInfo[0]);
// TODO Auto-generated method stub
Socket socket = null;
DataOutputStream dataOutputStream = null;
DataInputStream dataInputStream = null;
try {
socket = new Socket(clientInfo[0], 8888);
dataOutputStream = new DataOutputStream(socket.getOutputStream());
dataInputStream = new DataInputStream(socket.getInputStream());
dataOutputStream.writeUTF(editUsername.getText().toString());
dataOutputStream.writeUTF(editPassword.getText().toString());
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally{
if (socket != null){
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataOutputStream != null){
try {
dataOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataInputStream != null){
try {
dataInputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
} catch (java.io.IOException aE) {
aE.printStackTrace();
return null;
}
return getClientList1();
}
Submit action :
btnSubmit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
AttemptSubmit attemptSubmit= new AttemptSubmit();
attemptSubmit.getClientList1();
}
});
The problem is, when i click on submit button i'm getting this error "Unfortunately,Aqua has stooped."

How to accept multiple socket connection at Java server

I'm trying to implement a client-server pair in Android using standard Java sockets. So far, I've successfully implemented one to one client-server connection. Now, I'm modifying my server side code to accept multiple client connection. I've taken help from here. I'm creating a serverSocket and wait for client connection in an infinite while loop. Once the client side socked is accepted, I run a new thread to handle that client and then again wait for new connection. Unfortunately, the program keeps crashing for some unknown reason! The logcat simply says- "error opening trace file: No such file or directory". The file path is correct (it was working fine in older implementation). Can anyone suggest what am I doing wrong? Is it related to missing manifest permission? Here is what I've done so far:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent launchFileManager = new Intent(getBaseContext(),
FileChooserActivity.class);
startActivityForResult(launchFileManager, REQUEST_CODE); //receives files
//fileArray has been populated here
Button btn=(Button)findViewById(R.id.dispFilesid);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
initializeServer();
}
});
}
private void initializeServer() {
boolean listening = true;
try {
serversocket = new ServerSocket(4444);
} catch (IOException e) {
e.printStackTrace();
Log.d("Listen failed", "Listening to port 4444 failed");
}
while (listening) {
try {
socket = serversocket.accept();
Thread Clienttrd = new Thread(new Runnable() {
#Override
public void run() {
try {
OutputStream myos=socket.getOutputStream();
myos.write(filepathNameArray.size()); //send file count
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (!fileArray.isEmpty()) {
for (int i = 0; i < filepathNameArray.size(); i++){
copyFile(fileArray.get(i), fileArray.get(i).getName().toString());
//mtv.setText(fileArray.get(i).getName().toString());
}
}
}
});
Clienttrd.start();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
The intent for FileChooserActivity returns an ArrayList containing a list of file URIs. These URIs are then wrapped around files and written over DataOutputStream of Socket object.
Please help. Any insight would be appreciated! Thanks in advance!

Finally solved the problem. This might help others who land on this page in future. The problem: I was using the same thread for accepting and handling the client connection. So, the server could not become free for listening other incoming connections. I wrote a separate ConnectionHandler class for handling client connection:
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Thread trd = new Thread(new Runnable() {
#Override
public void run() {
try {
serversocket = new ServerSocket(4444);
} catch (IOException e) {
e.printStackTrace();
Log.d("Listen failed",
"Listening to port 4444 failed");
}
while (listening) {
try {
socket = serversocket.accept();
Runnable connectionHandler = new ConnectionHandler(
socket, fileArray, filepathNameArray);
new Thread(connectionHandler).start();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
});
trd.start();
}
});
ConnectionHandler (This solved my issue):
public class ConnectionHandler implements Runnable {
private Socket socket=null;
private ArrayList<File> fileArray=null;
ArrayList<String> filepathNameArray=null;
public ConnectionHandler(Socket socket, ArrayList<File> fileArray, ArrayList<String> filepathNameArray) {
super();
this.socket = socket;
this.fileArray=fileArray;
this.filepathNameArray=filepathNameArray;
}
#Override
public void run() {
try {
OutputStream myos=socket.getOutputStream();
myos.write(filepathNameArray.size()); //send file count
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (!fileArray.isEmpty()) {
for (int i = 0; i < filepathNameArray.size(); i++){
copyFile(fileArray.get(i), fileArray.get(i).getName().toString());
//mtv.setText(fileArray.get(i).getName().toString());
}
}
}
private void copyFile(File file, String name) {
FileInputStream fis;
long filesize = file.length();
try {
fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
#SuppressWarnings("resource")
DataInputStream dis = new DataInputStream(bis);
byte[] mybytearray = new byte[16384];
OutputStream os;
if (socket != null) {
os = socket.getOutputStream();
DataOutputStream dos = new DataOutputStream(os);
dos.writeUTF(name); // filename is also sent to client
dos.writeLong(filesize); // file size is also sent to client
long z = filesize;
int n = 0;
while ((z > 0)
&& (n = dis.read(mybytearray, 0,
(int) Math.min(mybytearray.length, z))) != -1) {
dos.write(mybytearray, 0, n);
dos.flush();
z -= n;
}
}
} catch (FileNotFoundException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}

Second connection to Bluetooth device fails in Android

I'm trying to establish a Bluetooth connection in Android 4.4 but the connect method of BluetoothSocket seems to be working strangely. My app can assume the device is already bonded, so I can connect via MAC address. The thing is that it connects perfectly and immediately the first time the device is bonded, but if I relaunch it, the connection isn't established and a timeout occurs. I do this inside a while loop until it connects, but it takes too long for a real solution or it doesn't work at all. Here's a sample of my code:
public class BluetoothManager{
private BluetoothAdapter bluetoothAdapter;
private BluetoothDevice bluetoothDevice;
private BluetoothSocket socket;
private OutputStream output;
private InputStream input;
public BluetoothManager() {
/***************/
/* Constructor */
/***************/
// lock = new Object();
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
}
public boolean turnOnBluetooth() {
/**************************************/
/* Turn on Bluetooth an notify result */
/**************************************/
// check if bluetooth is supported
if (bluetoothAdapter == null) {
return (false);
} else {
// enable Bluetooth if not enabled yet
if (!bluetoothAdapter.isEnabled()) {
bluetoothAdapter.enable();
}
while (!bluetoothAdapter.isEnabled()) {
Log.i("Debug", "Waiting for bluetooth to turn on");
try {
Thread.sleep(500);
} catch (Exception e) {
}
}
return (true);
}
}
public boolean turnOffBluetooth() {
/***************************************/
/* Turn off Bluetooth an notify result */
/***************************************/
// check if bluetooth is supported
if (bluetoothAdapter == null) {
return (false);
} else {
// disable Bluetooth if not enabled yet
if (bluetoothAdapter.isEnabled()) {
bluetoothAdapter.disable();
}
while (bluetoothAdapter.isEnabled()) {
Log.i("Debug
Thread.sleep(500);
} catch (Exception e) {
}
}
return (true);
}
}
public boolean configureBluetooth(String MACaddress) {
/***********************************************************************/
/* Configures to the specified bluetooth device and returns the result */
/***********************************************************************/
Log.i("Debug", "Connecting to Bluetooth Device");
bluetoothDevice = bluetoothAdapter.getRemoteDevice(MACaddress);
return (true);
}
#SuppressLint("NewApi")
public void createSocket() throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException{
final UUID serialUUID = UUID
.fromString("00001101-0000-1000-8000-00805F9B34FB");
socket = null;
output = null;
input = null;
Method m = bluetoothDevice.getClass().getMethod("createInsecureRfcommSocket", new Class[] { int.class });
socket = (BluetoothSocket)m.invoke(bluetoothDevice, 1);
}
#SuppressLint("NewApi")
public void connect() throws IOException, NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
/************************************/
/* Connects to the bluetooth device */
/************************************/
Log.i("Debug", "en connect");
while (!socket.isConnected()) { // we try until the connection is established
try {
socket.connect();
output = socket.getOutputStream();
input = socket.getInputStream();
} catch (IOException e) {
Log.i("Depuración", "Connection not established. Another run : "+e);
try {
Thread.sleep(1000);
} catch (Exception e1) {
}
}
}
}
public void terminateConnection() throws IOException {
Log.i("Debug", "terminating connection");
if(output!=null){
Log.i("Debug", "output!=null - stop streaming");
stopStreaming();
}
try {
Thread.sleep(100);
} catch (Exception e) {
}
if(input!=null){
Log.i("Debug", "input!=null");
input.close();
input=null;
}
if(output!=null){
Log.i("Depuración", "output!=null");
output.close();
output = null;
}
if(socket!=null){
Log.i("Debug", "socket!=null");
socket.close();
socket=null;
}
try {
Thread.sleep(100);
} catch (Exception e) {
}
turnOffBluetooth();
try {
Thread.sleep(100);
} catch (Exception e) {
}
try {
Thread.sleep(100);
} catch (Exception e) {
}
System.gc();
}
If I call this methods from my MainActivity, it works, but only the first time the device is bonded. If I launch the app again I get an exception trying to connect to the device in:
socket.connect();
I suspect it has something to do with the way I terminate the connection, but I can't figure it out. Here's the sequential call of the methods:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bluetoothManager = new BluetoothManager();
try {
bluetoothManager.terminateConnection();
} catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
bluetoothManager.turnOffBluetooth();
bluetoothManager.turnOnBluetooth();
boolean configured = false;
while (!configured) {
Log.i("Debug", "Configuration Attemp");
configured = bluetoothManager.configureBluetooth(MACaddress);
}
Log.i("Debug", "Bluetooth Configured");
try {
bluetoothManager.createSocket();
} catch (NoSuchMethodException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IllegalAccessException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IllegalArgumentException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (InvocationTargetException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
Log.i("Depuración", "Socket created");
try {
bluetoothManager.connect();
} catch (IOException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.i("Debug", "Connected!!!!");
protected void onPause() {
Log.i("Debug", "On pause");
// TODO Auto-generated method stub
try {
bluetoothManager.terminateConnection();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
bluetoothManager = null;
System.gc();
super.onPause();
};
I've been trying to solve this for days and I still can't find a reason.

Well I'm not a Pro on this, but it looks like you should call bluetoothManager.terminateConnection(); when app is closing, lets say onDestroy, but not onCreate; I also had problems to connect, if previous connection was not terminated correctly. just try add this method to your main activity:
#Override
public void onDestroy(){
if (bluetoothManager != null){
bluetoothManager.terminateConnection();
}
super.onDestroy();
}
hope that helps.

TCP in Android - ObjectOutputStream writeObject failure

I'm trying to send an Object from my phone to my PC(Windows) using a TCP socket via WiFi. When I try the same code between two PCs, it works without any error. But when I put the client code to the android device, it fails to send date using writeObject method. But writeUTF command works. It gives the "Software caused connection abort: recv failed" error. Below is the Code. Please help..
Server(in PC):
public class Test {
public static void main(String arg[]) {
ServerSocket serverSocket = null;
Socket socket = null;
ObjectInputStream in = null;
ObjectOutputStream out = null;
try {
serverSocket = new ServerSocket(8888);
System.out.println("Listening :8888");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
while (true) {
try {
socket = serverSocket.accept();
in = new ObjectInputStream(socket.getInputStream());
out = new ObjectOutputStream(socket.getOutputStream());
out.flush();
System.out.println("ip: " + socket.getInetAddress());
Message msg = (Message) in.readObject(); //Message captured from chat client.
System.out.println(msg.type + " message received from " + msg.sender + " Containing " + msg.content);
out.writeObject(new Message("Ack", "Server", "Message Received", "Client"));
out.flush();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException ex) {
Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
}
finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
}
Client (in Android Device):
public class MainActivity extends Activity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button bb=(Button)findViewById(R.id.button1);
bb.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
new Send().execute();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private class Send extends AsyncTask<Void, Void, Void> {
Socket socket = null;
ObjectOutputStream out = null;
ObjectInputStream in = null;
protected Void doInBackground(Void... arg0) {
try {
socket = new Socket("192.168.43.92", 8888); //use the IP address of the server
out = new ObjectOutputStream(socket.getOutputStream());
out.flush();
out.writeObject(new Message("Chat", "Server", "Hello World", "Server")); //This method is used to write something to the server.
out.flush();
Message msg = (Message) in.readObject();
System.out.println(msg.type + " message received from " + msg.sender + " Containing " + msg.content);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return null;
}
protected void onProgressUpdate(Integer... progress) {
//setProgressPercent(progress[0]);
}
protected void onPostExecute(Long result) {
//showDialog("Downloaded " + result + " bytes");
}
}
}
Message(in Both Sides):
public class Message implements Serializable{
private static final long serialVersionUID = 1L;
public String type, sender, content, recipient;
public Message(String type, String sender, String content, String recipient){
this.type = type; this.sender = sender; this.content = content; this.recipient = recipient;
}
#Override
public String toString(){
return "{type='"+type+"', sender='"+sender+"', content='"+content+"', recipient='"+recipient+"'}";
}
}

Is the network between the client and server setup properly via your WiFi? Download one of those ping & telnet test apps and use it to test your network connection.
Telnet is a useful TCP debugging app. If you have a server listening on 11.22.33.44 port 1234, you should be able to telnet 11.22.33.44 1234

Maybe, you need to add this functions into Message class:
private void writeObject(java.io.ObjectOutputStream stream)
throws IOException {
stream.writeObject(type);
stream.writeObject(sender);
stream.writeObject(content);
stream.writeObject(recipient);
}
private void readObject(java.io.ObjectInputStream stream)
throws IOException, ClassNotFoundException {
type = (String) stream.readObject();
sender = (String) stream.readObject();
content = (String) stream.readObject();
recipient = (String) stream.readObject();
}
http://developer.android.com/reference/java/io/Serializable.html

sending and receiving UDP packet on datagram socket in android

I have two classes,one sender class and the other is the receiver class.Both of the sending and receiving apps stops after few seconds and close down.
My sender class is :
public class MainActivity extends Activity {
InetAddress receiverAddress;
DatagramSocket datagramSocket;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
datagramSocket = new DatagramSocket(4444);
} catch (SocketException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
byte[] buffer = "0123456789".getBytes();
byte[] address="192.168.1.101".getBytes();
try {
receiverAddress = InetAddress.getByAddress(address);
} catch (UnknownHostException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
DatagramPacket packet = new DatagramPacket(
buffer, buffer.length, receiverAddress, 4444);
try {
datagramSocket.send(packet);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
My receiving or listening class is:
public class MainActivity extends Activity {
DatagramSocket datagramSocket;
DatagramPacket packet;
TextView tv1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv1=(TextView)findViewById(R.id.textView1);
try {
datagramSocket = new DatagramSocket(80);
} catch (SocketException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
byte[] buffer = new byte[10];
packet = new DatagramPacket(buffer, buffer.length);
try {
datagramSocket.receive(packet);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
byte[] buff = packet.getData();
tv1.setText(buff.toString());
}
Thanks in advance for the help.

In Android you're not allowed to execute Network operations on the UIThread (Main-Thread)
To Fix this:
Copy your network-code to a new Thread and let it run.

The port numbers in the "new DatagramSocket(...)" calls look weird. The client should create an "unbound" socket - simply use "new DatagramSocket();". The sender should bind to the port that the client sends to, i.e. "new DatagramSocket(4444);".

Source and destination port number should be same. Give same numbers in "DatagramSocket(xxx)". xxx must be same in both programs.