Develop Reference

Android Socket Client Receiving data

I am creating a basic test application for android that can connect to a socket server and send and receive data. i have been able to get the sending of data from the client to the server working but seem to have a problem getting the android to receive data. the server works as i have been able to test that using a external application.
here is my code
package com.socket_sending_and_receving_test;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.BufferedReader;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Timer;
import java.util.TimerTask;
import android.os.Looper;
import android.os.Message;
import android.widget.Button;
import android.widget.TextView;
import android.os.Handler;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
public class Sending_And_Receiving extends Activity {
private Socket socket;
String message = "";
String mClientMsg;
TextView text;
final Handler myHandler = new Handler();
int count = 0;
public static String SERVERPORT;
public static int SERVERPORT2;
public static String SERVER_IP;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sending_and_receaving);
text = (TextView) findViewById(R.id.textView);
text.setText("0");
}
Handler myUpdateHandler = new Handler() {
public void handleMessage(Message msg) {
TextView tv = (TextView) findViewById(R.id.textView);
tv.setText(mClientMsg);
super.handleMessage(msg);
}
};
class CommsThread implements Runnable {
String st = null;
public void run() {
while (!Thread.currentThread().isInterrupted()) {
Message m = new Message();
{
BufferedReader input = null;
try {
InputStreamReader streamReader = new InputStreamReader(socket.getInputStream());
BufferedReader reader = new BufferedReader(streamReader);
st = reader.readLine();
mClientMsg = st;
myUpdateHandler.sendMessage(m);
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
public void connect(View view) {
EditText ip = (EditText) findViewById(R.id.ip);
EditText port = (EditText) findViewById(R.id.port);
SERVER_IP = ip.getText().toString();
SERVERPORT = port.getText().toString();
new Thread(new ClientThread()).start();
new Thread(new CommsThread()).start();
}
public void Disconnect(View view) {
try {
socket.shutdownInput();
socket.shutdownOutput();
} catch (IOException e) {
e.printStackTrace();
}
}
public void onClick(View view) {
try {
EditText et = (EditText) findViewById(R.id.ko);
String str = et.getText().toString();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true
);
out.println(str);
} 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);
SERVERPORT2 = Integer.parseInt(SERVERPORT);
socket = new Socket(serverAddr, SERVERPORT2);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
after the connection is made the application crashes. I don't think it is due to the UI updating but i think its due to the receiving of data.
here is the logcat
07-08 21:59:57.915 7041-7041/com.socket_sending_and_receving_test D/libEGL﹕ loaded /system/lib/egl/libEGL_mali.so
07-08 21:59:57.920 7041-7041/com.socket_sending_and_receving_test D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_mali.so
07-08 21:59:57.925 7041-7041/com.socket_sending_and_receving_test D/libEGL﹕ loaded /system/lib/egl/libGLESv2_mali.so
07-08 21:59:57.930 7041-7041/com.socket_sending_and_receving_test D/﹕ Device driver API match
Device driver API version: 10
User space API version: 10
07-08 21:59:57.930 7041-7041/com.socket_sending_and_receving_test D/﹕ mali: REVISION=Linux-r2p4-02rel0 BUILD_DATE=Tue Oct 16 15:37:13 KST 2012
07-08 21:59:57.965 7041-7041/com.socket_sending_and_receving_test D/OpenGLRenderer﹕ Enabling debug mode 0
07-08 21:59:57.965 7041-7041/com.socket_sending_and_receving_test E/SensorManager﹕ thread start
07-08 21:59:57.970 7041-7041/com.socket_sending_and_receving_test D/SensorManager﹕ registerListener :: handle = 0 name= LSM330DLC 3-axis Accelerometer delay= 200000 Listener= android.view.OrientationEventListener$SensorEventListenerImpl#42b1cf38
07-08 21:59:58.080 7041-7041/com.socket_sending_and_receving_test E/SpannableStringBuilder﹕ SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
07-08 21:59:58.080 7041-7041/com.socket_sending_and_receving_test E/SpannableStringBuilder﹕ SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
07-08 22:00:03.235 7041-7193/com.socket_sending_and_receving_test W/dalvikvm﹕ threadid=13: thread exiting with uncaught exception (group=0x41e792a0)
07-08 22:00:03.240 7041-7193/com.socket_sending_and_receving_test E/AndroidRuntime﹕ FATAL EXCEPTION: Thread-2791
java.lang.NullPointerException
at com.socket_sending_and_receving_test.Sending_And_Receiving$CommsThread.run(Sending_And_Receiving.java:74)
at java.lang.Thread.run(Thread.java:856)
07-08 22:00:03.320 7041-7041/com.socket_sending_and_receving_test D/SensorManager﹕ unregisterListener:: Listener= android.view.OrientationEventListener$SensorEventListenerImpl#42b1cf38
07-08 22:00:03.320 7041-7041/com.socket_sending_and_receving_test D/Sensors﹕ Remain listener = Sending .. normal delay 200ms
07-08 22:00:03.320 7041-7041/com.socket_sending_and_receving_test I/Sensors﹕ sendDelay --- 200000000
07-08 22:00:03.320 7041-7041/com.socket_sending_and_receving_test D/SensorManager﹕ JNI - sendDelay
07-08 22:00:03.320 7041-7041/com.socket_sending_and_receving_test I/SensorManager﹕ Set normal delay = true
07-08 22:00:09.870 7041-7041/com.socket_sending_and_receving_test I/Choreographer﹕ Skipped 392 frames! The application may be doing too much work on its main thread.
07-08 22:00:11.680 7041-7193/com.socket_sending_and_receving_test I/Process﹕ Sending signal. PID: 7041 SIG: 9
Any help on this problem would be greatly appreciated
Cheers :)

Your socket is NULL. This is because of a race condition:
new Thread(new ClientThread()).start();
new Thread(new CommsThread()).start();
Both threads are started here, but ClientThread will initialise the socket while CommsThread tries to use it. But it is not initialised at this point.
You may call CommsThread's run() right after socket=... or if you really need a 2nd thread, start it there.

Your CommsThread is running before your ClientThread has completed the connection. So, 'socket' is still null and you get an NPE.
There is absolutely no reason for these to be two different threads. Combine them, so that the connection is made first and then the I/O starts. Using two threads to perform tasks that must be sequential is basically inane.

android emulator memory options stop my app from running

I seem to be having major problems with my eclipse emulator and don't know if it's the ram size or my code. In my opinion, my code should run, as it does so in my java netbeans project.
Everytime I run my application and push the connect button, I want to get the string that the server sends back and then do something with it. I have a "Process Connection" method that reads in the string, but when I return it and actually use what is being returned, my emulator crashes
My code is as follows:
package za.nmmu.wrap302.networks.example02;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnKeyListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;
public class MainActivity extends Activity {
private ListView lstMessages;
private EditText txtMessage;
private ArrayList<String> messages;
private ArrayAdapter<String> adapter;
String message = "";
private ServerConnection connection;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// get references to View objects
txtMessage = (EditText) findViewById(R.id.txtMessage);
lstMessages = (ListView) findViewById(R.id.lstMessages);
// set up adapter
messages = new ArrayList<String>();
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, messages);
lstMessages.setAdapter(adapter);
// attach event listener
txtMessage.setOnKeyListener(new OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_ENTER)
&& (event.getAction() == KeyEvent.ACTION_DOWN)) {
try {
onTxtMessageEnterPressed();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return true;
}
return false;
}
});
}
public void onBtnConnectClicked(View view) {
clearMessages();
connection = new ServerConnection();
connection.start();
}
public void onTxtMessageEnterPressed() throws IOException {
if (connection != null) {
String message = txtMessage.getText().toString();
txtMessage.getText().clear();
connection.sendData(message);
}
}
public void addMessage(String message) {
adapter.add(message);
}
public void clearMessages() {
adapter.clear();
}
// the thread that will be communicating with the server
public class ServerConnection extends Thread {
// the I/O streams that will be receiving/sending data from/to the
// server
private ObjectOutputStream output;
private ObjectInputStream input;
private Socket client;
#Override
public void run() {
try {
// Step 1: Create a Socket to make connection
connectToServer();
// Step 2: Get the input and output streams
getStreams();
// Step 3: Process connection
processConnection();
// Step 4: Close connection
//closeConnection();
} catch (IOException e) {
Log.e("CONNECTION", e.getMessage());
}
}
public void addMessage(final String message) {
runOnUiThread(new Runnable() {
#Override
public void run() {
MainActivity.this.addMessage(message);
}
});
}
private void connectToServer() throws IOException {
addMessage("Attempting connection\n");
client = new Socket("10.0.0.7", 5001);
addMessage("Connected to: " + client.getInetAddress().getHostName());
}
private void getStreams() throws IOException {
output = new ObjectOutputStream(client.getOutputStream());
output.flush();
input = new ObjectInputStream(client.getInputStream());
addMessage("Got I/O streams");
}
//I would like to call the message below and return it to anywhere else in the code
private String processConnection() throws IOException
{
do {
try {
message = (String) input.readObject();
addMessage(message);
return message;
}
catch (ClassNotFoundException classNotFoundException)
{
addMessage("ERROR: Unknown object type received");
}
return message;
} while (!message.equals("SERVER>>> TERMINATE"));
}
private void sendData(String message) {
try {
output.writeObject(message);
output.flush();
addMessage("CLIENT>>>" + message);
} catch (IOException ioException) {
addMessage("ERROR: Error writing object");
}
}
private void closeConnection() throws IOException {
addMessage("Closing connection");
output.close();
input.close();
client.close();
}
}
}
My application seems to just crash whenever I call the processConnection method from anywhere.
My server picks up that I've sent the message, but my client doesn't read.
http://i.stack.imgur.com/cNu7m.png
My logcat shows:
06-13 08:18:00.460: D/dalvikvm(1145): GC_FOR_ALLOC freed 45K, 4% free 3076K/3204K, paused 293ms, total 296ms
06-13 08:18:00.460: I/dalvikvm-heap(1145): Grow heap (frag case) to 3.687MB for 635812-byte allocation
06-13 08:18:00.530: D/dalvikvm(1145): GC_FOR_ALLOC freed 1K, 4% free 3695K/3828K, paused 55ms, total 55ms
06-13 08:18:02.220: I/Choreographer(1145): Skipped 172 frames! The application may be doing too much work on its main thread.
06-13 08:18:02.240: D/gralloc_goldfish(1145): Emulator without GPU emulation detected.
06-13 08:18:03.100: I/Choreographer(1145): Skipped 198 frames! The application may be doing too much work on its main thread.
06-13 08:18:27.660: E/InputEventSender(1145): Exception dispatching finished signal.
06-13 08:18:27.660: E/MessageQueue-JNI(1145): Exception in MessageQueue callback: handleReceiveCallback
Does the ram in the emulator affect this? What am I doing wrong?

You need to use Async task to spawn off uploading to a different thread. Android works on a single thread model and using the same thread to make HTTPRequest can result in FATAL exception. Create an Async task and spawn off the upload to it.
AsyncTaskRunner runner = new AsyncTaskRunner();
runner.execute(<pass the required parameters here for file upload>);
private class AsyncTaskRunner extends AsyncTask<String, String, String> {
#Override
protected String doInBackground(String... params) {
//Call the function to upload the file here
}
This is what the logcat is telling you by Main thread is doing too many tasks.

Application stopped unexpectedly: Fatal Exception

could anyone help my with my app code. I tryied to make an application that could send data (number or letter) to arduino through bluetooth. This is how my JAVA code look:
package com.example.btprojektas;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;
public class MainActivity extends Activity{
private static final String TAG = "btprojektas";
Button btnON, btnOFF;
BluetoothAdapter bluetoothAdapter = null;
BluetoothDevice device = null;
OutputStream outputStream = null;
BluetoothSocket socket = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
btnON = (Button) findViewById(R.id.btnON);
btnOFF = (Button) findViewById(R.id.btnOFF);
if(!bluetoothAdapter.isEnabled()){
Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBluetooth, 0);
}
loadPairedDevice();
connectBT();
btnON.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
sendData("0");
Toast.makeText(getBaseContext(), "Turn on LED", Toast.LENGTH_SHORT).show();
}
});
btnOFF.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
sendData("1");
Toast.makeText(getBaseContext(), "Turn off LED", Toast.LENGTH_SHORT).show();
}
});
}
private void connectBT() {
if (device != null) {
UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); //Standard SerialPortService ID
try {
socket = device.createRfcommSocketToServiceRecord(uuid);
socket.connect();
outputStream = socket.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void disconnect() {
try {
if (outputStream != null) outputStream.close();
if (socket != null) socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private void loadPairedDevice() {
Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
Log.d(TAG, "Device found");
for (BluetoothDevice device : pairedDevices)
if (device.getName().equals("HC-06")) {
this.device = device;
break;
}
}
}
#Override
protected void onPause() {
super.onPause();
disconnect();
}
#Override
protected void onResume() {
super.onResume();
loadPairedDevice();
connectBT();
}
private void sendData(String message) {
byte[] buffer = message.getBytes();
Log.d(TAG,"Send data:"+ message);
try{
outputStream.write (buffer);
} catch (IOException e) {}
}
}
in XML I have two buttons. When the program starts I push one of those buttons and the "Applications ... stopped unexpectedly" appears with fatal exeption fault code:
01-08 15:55:15.439 15354-15354/com.example.btprojektas E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at com.example.btprojektas.MainActivity.sendData(MainActivity.java:122)
at com.example.btprojektas.MainActivity.access$000(MainActivity.java:22)
at com.example.btprojektas.MainActivity$1.onClick(MainActivity.java:55)
at android.view.View.performClick(View.java:2485)
at android.view.View$PerformClick.run(View.java:9080)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3687)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
at dalvik.system.NativeStart.main(Native Method)
P.S. Sorry for this question I know that it is quite common but I am new at programming especially JAVA.

It's either the socket or the outputStream. In ConnectBT, you don't check if socket is not null. You directly call socket.connect() assuming socket is valid. The same applies to outputStream. You use it before making sure it's not null.
Also you call
startActivityForResult(enableBluetooth, 0);
but you don't check for the result which is whether bluetooth got enabled or not. This makes your device also suspicious.
Calling
loadPairedDevice();
connectBT();
makes sense only when bluetooth is enabled. Enabling bluetooth can take couple of seconds, but you call them right away.

A couple of tips:
you're calling loadPairedDevice() and connectBT() twice: in onCreate() and in onResume() - do it only once
before using outputStream, check if it's not null (as advised by others)
in sendData(), catch AND print your exception:
try {
if (outputStream != null) {
outputStream.write(buffer);
}
else {
Log.d("TAG", "sendData() - outputStream is null!");
}
}
catch (IOException e) {
e.printStackTrace();
}
in loadPairedDevice(), if you don't find the device "HC-06", your variable device will be null...
enabling bluetooth takes few seconds, so register and listen to ACTION_STATE_CHANGED broadcast Intent. It will contain extra field EXTRA_STATE; look for STATE_ON, and then call your loadPairedDevices() and connectBT() there:
create receiver (inside your MainActivity class):
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
//this is the action you are observing
if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);
switch(state) {
//and the state we were looking for
//which means that bluetooth has switched on
//so now you can call your functions
//and set the flag to true, which then use in your
//onClick listeners
case BluetoothAdapter.STATE_ON:
loadPairedDevice();
connectBT();
isBluetoothOn = true;
break;
}
}
}
}
in onCreate(), create IntentFilter and register receiver with it
IntentFilter btFilter = new IntentFilter();
btFilter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mReceiver, btFilter);
remember to unregister receiver in onPause():
unregisterReceiver(mReceiver);
disable your buttons and enable them in the above listener, when you know BT is switched on; alternatively, keep a flag and use it in your click listeners, eg.:
boolean isBluetoothOn = false;
then later in listener when you get STATE_ON
isBluetooth = true;
And in your button click listener:
//for btnON
public void onClick(View v) {
if (isBluetoothOn) {
sendData("0");
Toast.makeText(getBaseContext(), "Turn on LED", Toast.LENGTH_SHORT).show();
}
}
Do the same for btnOFF.

Programmatically pair Bluetooth device without the user entering pin

The Bluetooth device I am trying to connect has always the same pincode. This should make it possible to pair the device by setting the pin programmatically.
After trying to search how this could be done, I ended up with the code below:
BluetoothDevice device = getDevice();
//To avoid the popup notification:
device.getClass().getMethod("setPairingConfirmation", boolean.class).invoke(device, true);
device.getClass().getMethod("cancelPairingUserInput", boolean.class).invoke(device, true);
byte[] pin = ByteBuffer.allocate(4).putInt(1234).array();
//int pinn = 1234;
//Entering pin programmatically:
Method ms = device.getClass().getMethod("setPin", byte[].class);
//Method ms = device.getClass().getMethod("setPasskey", int.class);
ms.invoke(device, pin);
//Bonding the device:
Method mm = device.getClass().getMethod("createBond", (Class[]) null);
mm.invoke(device, (Object[]) null);
cancelPairingUserInput gives me a NoSuchMethodException, which is weird because the method does exist in BluetoothDevice class.
Is looks like Setpin or SetPasskey doesn't do anything. The device just wont pair. It only pairs after manually entering the pin.
So the only line of code that works is:
//Bonding the device:
Method mm = device.getClass().getMethod("createBond", (Class[]) null);
mm.invoke(device, (Object[]) null);
Logcat output:
09-27 12:34:46.408: ERROR/App(11671): cancelPairingUserInput [boolean]
java.lang.NoSuchMethodException: cancelPairingUserInput [boolean]
at java.lang.Class.getConstructorOrMethod(Class.java:460)
at java.lang.Class.getMethod(Class.java:915)
at test.app.bluetooth.model.BluetoothDiscoveryAndPairing.pair(BluetoothDiscoveryAndPairing.java:97)
at test.app.bluetooth.model.BluetoothDiscoveryAndPairing.access$000(BluetoothDiscoveryAndPairing.java:25)
at test.app.bluetooth.model.BluetoothDiscoveryAndPairing$1.onReceive(BluetoothDiscoveryAndPairing.java:79)
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:756)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
at dalvik.system.NativeStart.main(Native Method)
So what am I doing wrong?

The hidden method cancelPairingUserInput does not exist in your device. Don't use it.
You should register BroadcastReceiver for android.bluetooth.device.action.PAIRING_REQUEST
Call createBond()
Wait for BroadcastReceiver to trigger
In BroadcastReceiver if action is android.bluetooth.device.action.PAIRING_REQUEST
call this method
public void setBluetoothPairingPin(BluetoothDevice device)
{
byte[] pinBytes = convertPinToBytes("0000");
try {
Log.d(TAG, "Try to set the PIN");
Method m = device.getClass().getMethod("setPin", byte[].class);
m.invoke(device, pinBytes);
Log.d(TAG, "Success to add the PIN.");
try {
device.getClass().getMethod("setPairingConfirmation", boolean.class).invoke(device, true);
Log.d(TAG, "Success to setPairingConfirmation.");
} catch (Exception e) {
// TODO Auto-generated catch block
Log.e(TAG, e.getMessage());
e.printStackTrace();
}
} catch (Exception e) {
Log.e(TAG, e.getMessage());
e.printStackTrace();
}
}
It also works on a device with Jelly Bean version (4.1.2) of Android.

this is works for me:
IntentFilter filter2 = new IntentFilter(
"android.bluetooth.device.action.PAIRING_REQUEST");
mActivity.registerReceiver(
pairingRequest, filter2);
private final BroadcastReceiver pairingRequest = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("android.bluetooth.device.action.PAIRING_REQUEST")) {
mBluetoothDevice = needed;
try {
byte[] pin = (byte[]) BluetoothDevice.class.getMethod("convertPinToBytes", String.class).invoke(BluetoothDevice.class, "1234");
Method m = mBluetoothDevice.getClass().getMethod("setPin", byte[].class);
m.invoke(mBluetoothDevice, pin);
mBluetoothDevice.getClass().getMethod("setPairingConfirmation", boolean.class).invoke(mBluetoothDevice, true);
}
catch(Exception e)
{
e.printStackTrace();
}

TCP socket on Android 4.0.3

I am working on a project in which I have a TCP connection with a server via Android.
I am using the following code:
public class MyService extends Service {
private static final String TAG = "MyService";
MediaPlayer player;
Socket s;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
Toast.makeText(this, "My Service Created", Toast.LENGTH_LONG).show();
Log.d(TAG, "onCreate");
player = MediaPlayer.create(this, R.raw.braincandy);
player.setLooping(false); // Set looping
}
#Override
public void onDestroy() {
Toast.makeText(this, "My Service Stopped", Toast.LENGTH_LONG).show();
Log.d(TAG, "onDestroy");
player.stop();
try {
s.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void onStart(Intent intent, int startid) {
Toast.makeText(this, "My Service Started", Toast.LENGTH_LONG).show();
Log.d(TAG, "onStart");
player.start();
try {
s = new Socket("192.168.1.54", 64000);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
I am running the connection as a service.
The real problem is I can make a connection with my Android phone (2.3.7) and with the emulator (2.3.3) but when I want to test in on my tablet (4.0.3), my app always crashes when I want to start the connection.
Can someone help me with this?
Here is the logcat log:
FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start service
com.gunther.servicetcp.MyService#412b0a98 with Intent
{ cmp=com.gunther.servicetcp/.MyService }: android.os.NetworkOnMainThreadException
at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2376)
at android.app.ActivityThread.access$1900(ActivityThread.java:123)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.os.NetworkOnMainThreadException
0at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
at libcore.io.IoBridge.connect(IoBridge.java:112)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.Socket.startupSocket(Socket.java:566)
at java.net.Socket.tryAllAddresses(Socket.java:127)
at java.net.Socket.<init>(Socket.java:177)
at java.net.Socket.<init>(Socket.java:149)
at com.gunther.servicetcp.MyService.onStart(MyService.java:53)
at android.app.Service.onStartCommand(Service.java:438)
at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2359)
: ... 10 more

You shouldn't do network operations on the main thread. This will lead to your app being unresponsive. Before Honeycomb you could get away with it, but Honeycomb and newer Android versions will check and throw the exception you're getting. See also this page of the Android Developers API

Services's onStart() method runs on the main thread, (yes, services seem to run on the main thread of the application.) so you should fork another thread in the onStart() method and do everything you need to do in that thread.