Develop Reference

Send String via bluetooth OnClick()

I am trying to send String message via Bluetooh. I am using code from this post:send message
I would like to send message on OnClick() to another connected device. Currently i can display paired devices and i am able to connect with them.
P.S I am trying to send message in write() function. When i tried to debug the code, i've figured out that debugger don't enter toMESSAGE WRITE on MESSAGE READ statement. Thanks for any help.
public class BluetoothActivity extends AppCompatActivity {
public static final int REQUEST_ENABLE_BT=1;
ListView lv_paired_devices;
Button sendMessage;
Set<BluetoothDevice> set_pairedDevices;
ArrayAdapter adapter_paired_devices;
BluetoothAdapter bluetoothAdapter;
public static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
public static final int MESSAGE_READ=0;
public static final int MESSAGE_WRITE=1;
public static final int CONNECTING=2;
public static final int CONNECTED=3;
public static final int NO_SOCKET_FOUND=4;
String bluetooth_message="00";
#SuppressLint("HandlerLeak")
Handler mHandler=new Handler()
{
#Override
public void handleMessage(Message msg_type) {
super.handleMessage(msg_type);
switch (msg_type.what){
case MESSAGE_READ:
byte[] readbuf=(byte[])msg_type.obj;
String string_recieved=new String(readbuf);
Log.i("TAGREAD", "Bluetooth not supported");
Toast.makeText(getApplicationContext(),string_recieved,Toast.LENGTH_LONG).show();
//do some task based on recieved string
break;
case MESSAGE_WRITE:
if(msg_type.obj!=null){
ConnectedThread connectedThread=new ConnectedThread((BluetoothSocket)msg_type.obj);
connectedThread.write(bluetooth_message.getBytes());
Log.i("TAGWRITE", "Bluetooth not supported");
}
break;
case CONNECTED:
Toast.makeText(getApplicationContext(),"Connected",Toast.LENGTH_SHORT).show();
break;
case CONNECTING:
Toast.makeText(getApplicationContext(),"Connecting...",Toast.LENGTH_SHORT).show();
break;
case NO_SOCKET_FOUND:
Toast.makeText(getApplicationContext(),"No socket found",Toast.LENGTH_SHORT).show();
break;
}
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().setTitle("Sparowane urządzenia");
bluetoothAdapter=BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
Log.i("TAGTAG", "Bluetooth not supported");
// Show proper message here
finish();
}
else{
setContentView(R.layout.activity_bluetooth);
initialize_layout();
initialize_bluetooth();
start_accepting_connection();
initialize_clicks();
}
}
public void start_accepting_connection()
{
//call this on button click as suited by you
AcceptThread acceptThread = new AcceptThread();
acceptThread.start();
Toast.makeText(getApplicationContext(),"accepting",Toast.LENGTH_SHORT).show();
}
public void initialize_clicks()
{
lv_paired_devices.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
Object[] objects = set_pairedDevices.toArray();
BluetoothDevice device = (BluetoothDevice) objects[position];
ConnectThread connectThread = new ConnectThread(device);
connectThread.start();
Toast.makeText(getApplicationContext(),"device choosen "+device.getName(),Toast.LENGTH_SHORT).show();
}
});
}
public void initialize_layout()
{
lv_paired_devices = (ListView)findViewById(R.id.lv_paired_devices);
adapter_paired_devices = new ArrayAdapter(getApplicationContext(),R.layout.support_simple_spinner_dropdown_item);
lv_paired_devices.setAdapter(adapter_paired_devices);
sendMessage=findViewById(R.id.send_button);
}
public void initialize_bluetooth()
{
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
// Device doesn't support Bluetooth
Toast.makeText(getApplicationContext(),"Your Device doesn't support bluetooth. you can play as Single player",Toast.LENGTH_SHORT).show();
finish();
}
//Add these permisions before
// <uses-permission android:name="android.permission.BLUETOOTH" />
// <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
// <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
// <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
if (!bluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
else {
set_pairedDevices = bluetoothAdapter.getBondedDevices();
if (set_pairedDevices.size() > 0) {
for (BluetoothDevice device : set_pairedDevices) {
String deviceName = device.getName();
String deviceHardwareAddress = device.getAddress(); // MAC address
adapter_paired_devices.add(device.getName() + "\n" + device.getAddress());
}
}
}
}
public class AcceptThread extends Thread
{
private final BluetoothServerSocket serverSocket;
public AcceptThread() {
BluetoothServerSocket tmp = null;
try {
// MY_UUID is the app's UUID string, also used by the client code
tmp = bluetoothAdapter.listenUsingRfcommWithServiceRecord("NAME",MY_UUID);
} catch (IOException e) { }
serverSocket = tmp;
}
public void run() {
BluetoothSocket socket = null;
// Keep listening until exception occurs or a socket is returned
while (true) {
try {
socket = serverSocket.accept();
} catch (IOException e) {
break;
}
// If a connection was accepted
if (socket != null)
{
// Do work to manage the connection (in a separate thread)
mHandler.obtainMessage(CONNECTED).sendToTarget();
}
}
}
}
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to mmSocket,
// because mmSocket is final
BluetoothSocket tmp = null;
mmDevice = device;
// Get a BluetoothSocket to connect with the given BluetoothDevice
try {
// MY_UUID is the app's UUID string, also used by the server code
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) { }
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it will slow down the connection
bluetoothAdapter.cancelDiscovery();
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mHandler.obtainMessage(CONNECTING).sendToTarget();
mmSocket.connect();
} catch (IOException connectException) {
// Unable to connect; close the socket and get out
try {
mmSocket.close();
} catch (IOException closeException) { }
return;
}
// Do work to manage the connection (in a separate thread)
// bluetooth_message = "Initial message"
// mHandler.obtainMessage(MESSAGE_WRITE,mmSocket).sendToTarget();
}
/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[2]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI activity
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();
Toast.makeText(BluetoothActivity.this,bytes,Toast.LENGTH_LONG).show();
} catch (IOException e) {
break;
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
sendMessage.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
mmOutStream.write(bytes);
} catch (IOException e) { }
}
});
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}

getting device not paired after pairing in my Bluetooth app

i am building an app to display the Ecg in mobile .so i try to
establish a connection via bluetooth .but when i try to pair the
Bluetooth, the paired devices are shown. but when i try to connect, it
says device not found..i don't know how to solve the problem. Please
advise on issues in my code to connect to paired devices:Any help on
this would be greatly appreciate
this is my bluetooth.java
public class bluetooth extends Activity implements AdapterView.OnItemClickListener {
public static void disconnect(){
if (connectedThread !=null){
connectedThread.cancel();
connectedThread= null;
}
}
public static void gethandler(Handler handler){
mHandler= handler;
}
static Handler mHandler =new Handler();
static ConnectedThread connectedThread;
public static final UUID my_UUID= UUID.fromString("f53a07d4-3010-11e9-b210-d663bd873d93");
protected static final int SUCCESS_CONNECT=0;
protected static final int MESSAGE_READ=1;
ListView listView;
//ArrayAdapter is an Android SDK class for adapting an array of objects as a datasource.
// Adapters are used by Android to treat a result set uniformly whether it's from a database, file, or in-memory objects
// so that it can be displayed in a UI element.
// The ArrayAdapter is useful for the latter. Use it anywhere you would use an Adapter. E.g. attach to Android UI elements.
ArrayAdapter<String> list_adapter;
static BluetoothAdapter btAdapter;
Set<BluetoothDevice> devicesArray;
///ArrayList is an implementation of java.util.List that's backed by an array. You can use it anywhere you would use a java.util.List.
//// E.g. where you need to maintain order of a collection of objects where duplicates are allowed.
ArrayList<String> pairedDevices;
ArrayList<BluetoothDevice> devies;
IntentFilter filter;
BroadcastReceiver receiver;
#Override
protected void onCreate( Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//in Android the visual design is created in xml . And each Activity is associated to a design
//
//setContentView(R.layout.main)
//R means Resource
//
//layout means design
//
//main is the xml you have created under res->layout->main.xml
//
//Whenever you want to change your current Look of an Activity or when you move from
// one Activity to another . The other Activity must have a design to show . So we call this method in onCreate
// and this is the second statement to set the design
setContentView(R.layout.activity_bluetooth);
init();
if(btAdapter==null){
Toast.makeText(getApplicationContext(),"no bt detected", Toast.LENGTH_SHORT).show();
Log.d(TAG, "onCreate: no");
finish();
}
else{
if(!btAdapter.isEnabled()){
turnOnBT();
}
getPairedDevices();
startDiscovery();
}
}
private void getPairedDevices(){
btAdapter.cancelDiscovery();
btAdapter.startDiscovery();
}
private void turnOnBT(){
Intent intent=new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(intent,1);
}
private void startDiscovery(){
devicesArray = btAdapter.getBondedDevices();
if(devicesArray.size()>0){
for(BluetoothDevice device:devicesArray){
pairedDevices.add(device.getName());
String s="";
list_adapter.add(device.getName()+" "+s+""+"\n"+device.getAddress());
}
}
}
private void init() {
listView =(ListView)findViewById(R.id.list_item);
listView.setOnItemClickListener(this);
list_adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,0);
listView.setAdapter(list_adapter);
btAdapter = BluetoothAdapter.getDefaultAdapter();
pairedDevices =new ArrayList<String>();
filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
devies = new ArrayList<BluetoothDevice>();
receiver =new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action =intent.getAction();
if(BluetoothDevice.ACTION_FOUND.equals(action)){
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
devies.add(device); //!!!!!!!!!!
String s="";
for (int a=0;a<pairedDevices.size();a++){
if(device.getName().equals(pairedDevices.get(a))){
s="(paired)";
break;
}
}
list_adapter.add(device.getName()+" "+s+""+"\n"+device.getAddress());
}
else if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)){
}else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)){
}else if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)){
if(btAdapter.getState()==btAdapter.STATE_OFF){
turnOnBT();
}
}
}
};
registerReceiver(receiver, filter);
IntentFilter filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
registerReceiver(receiver, filter);
filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
registerReceiver(receiver, filter);
filter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
}
#Override
protected void onPause() {
super.onPause();
unregisterReceiver(receiver);
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_CANCELED){
Toast.makeText(getApplicationContext(), "Bluetooth must be enabled to continue", Toast.LENGTH_SHORT).show();
finish();
}
}
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if(btAdapter.isDiscovering()){
btAdapter.cancelDiscovery();
}
if(list_adapter.getItem(position).contains("(paired)")){
BluetoothDevice selectedDevice = devies.get(position);
ConnectThread connect = new ConnectThread(selectedDevice);
connect.start();
}
else{
Toast.makeText(getApplicationContext(),"device not paired", Toast.LENGTH_SHORT).show();
}
}
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to mmSocket,
// because mmSocket is final
BluetoothSocket tmp = null;
mmDevice=device;
// Get a BluetoothSocket to connect with the given BluetoothDevice
try {
// MY_UUID is the app's UUID string, also used by the server code
tmp = device.createRfcommSocketToServiceRecord(my_UUID);
} catch (IOException e) { }
mmSocket = tmp;
}
public void run() {
// Cancel discover y because it will slow down the connection
btAdapter.cancelDiscovery();
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mmSocket.connect();
//connectedThread = new ConnectedThread(mmSocket);
} catch (IOException connectException) {
// Unable to connect; close the socket and get out
try {
mmSocket.close();
} catch (IOException closeException) { }
return;
}
// Do work to manage the connection (in a separate thread)
mHandler.obtainMessage(SUCCESS_CONNECT, mmSocket).sendToTarget();
}
/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
// Incoming and the outgoing strings are carried out inside this thread read is for reading incoming messages through a socket and write is for sending messages to the remote device
static class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
// socket not created
e.printStackTrace();
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
StringBuffer sbb = new StringBuffer();
public void run() {
byte[] buffer ;
int bytes;
// receiving message
while(true) {
try {
try {
sleep(30);
} catch (InterruptedException e) {
break;
}
buffer = new byte[1024];
// Read from the InputStream
bytes = mmInStream.read(buffer);
// message is in bytes form so reading them to obtain message
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();
} catch (IOException e) {
// connection was lost and start your connection again
Log.e(TAG, "disconnected", e);
break;
}
}
}
public void write(String income) {
try {
mmOutStream.write(income.getBytes());
for (int i=0;i<income.getBytes().length;i++)
Log.v("outStream"+Integer.toString(i),Character.toString((char)(Integer.parseInt(Byte.toString(income.getBytes()[i])))));
try{
Thread.sleep(20);
}
catch (InterruptedException e1){
e1.printStackTrace();
}
} catch (IOException e1) {
e1.printStackTrace();
}
}
public void cancel(){
try {
mmSocket.close();
}
catch (IOException e){}
}
}
}
but my question is, are there any problem with mmsocket
enter image description here
i geeting like beow in my android phone.
enter image description here

Can't establish Bluetooth connection between my app and remote Bluetooth HC-05

I'm developing an Android app that is a kind of a remote control (that works via bluetooth) for one Arduino device. I've already could pair my phone with remote Bluetooth. Also it seems that I could establish connection which I've checked with an ACTION_ACL_CONNECTED state like this:
private final BroadcastReceiver connectedReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
showToast("Conneeeeeeeeeeeeected");
}
}
};
The problem is when I press a button on my app to send some data to the remote Bluetooth, nothing happens (a LED must change its state from OFF to ON). Could you please check what's wrong, maybe it's something with my ConnectThread? Here is my code:
public class MainActivity extends AppCompatActivity {
private final static UUID MY_UUID = UUID.fromString("ecff8f1a-ac66-11e6-80f5-76304dec7eb7");
BluetoothSocket mmSocket;
Button whiteBtn; // after clicking this button, data from my phone are send to remote bluetooth
whiteBtn = (Button) findViewById(R.id.white_btn);
whiteBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
whiteBtnOn();
}
});
#Override
protected void onCreate(Bundle savedInstanceState) {
// Get Bluetooth Adapter
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
showToast("Bluetooth is not supported on this device");
}
// Enable Bluetooth
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, arrListPaired);
pairedListView.setAdapter(mPairedDevicesArrayAdapter);
// Find out which devices have been already paired
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
showToast("Paired devices have been found");
// Loop through the paired devices
for (BluetoothDevice device : pairedDevices) {
arrListPaired.add(device.getName() + '\n' + device.getAddress());
mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, arrListPaired);
}
pairedListView.setAdapter(mPairedDevicesArrayAdapter);
}
// Click event for items from paired devices list (Possible actions: “Connect”, which establishes connection between my phone and remote Bluetooth, “Unpair”, “Cancel”)
pairedListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, final View view, final int position, long id) {
final String info = ((TextView) view).getText().toString();
int address = info.indexOf(":");
final String adr = info.substring(address - 2, info.length());
final int positionToRemove = position;
final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setMessage("What should we do?");
//builder.setMessage("Unpair this device?");
builder.setPositiveButton("Unpair", new OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(adr);
// UNPAIR DEVICES
unpair(device);
arrListPaired.remove(positionToRemove);
mPairedDevicesArrayAdapter.notifyDataSetChanged();
// END UNPAIR DEVICES
}
});
builder.setNeutralButton("Cancel", new OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
dialogInterface.cancel();
}
});
// Establish Connection between devices
builder.setNegativeButton("Connect", new OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
showToast("Establish connection");
BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(adr);
ConnectThread ct = new ConnectThread(device);
ct.start();
IntentFilter filter = new IntentFilter();
filter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
registerReceiver(connectedReceiver, filter);
}
});
AlertDialog alertDialog = builder.create();
alertDialog.show();
}
});
#Override
protected void onPause() {
if (mBluetoothAdapter != null) {
if (mBluetoothAdapter.isDiscovering()) {
mBluetoothAdapter.cancelDiscovery();
}
}
super.onPause();
}
#Override
protected void onDestroy() {
unregisterReceiver(mReceiver);
super.onDestroy();
}
private void showToast(String message) {
Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
}
private void pairDevice(BluetoothDevice device) {
try {
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
registerReceiver(receiver, filter);
Method method = device.getClass().getMethod("createBond", (Class[]) null);
method.invoke(device, (Object[]) null);
} catch (Exception e) {
e.printStackTrace();
}
}
private void unpair(BluetoothDevice device) {
showToast("Unpaired button is clicked");
try {
if(mmSocket!=null) {mmSocket.close();}
Method m = device.getClass().getMethod("removeBond", (Class[]) null);
m.invoke(device, (Object[]) null);
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
// Connecting threat
private class ConnectThread extends Thread {
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
BluetoothSocket tmp = null;
mmDevice = device;
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {}
mmSocket = tmp;
}
public void run () {
mBluetoothAdapter.cancelDiscovery();
try {
mmSocket.connect();
} catch (IOException connectException) {
try {
mmSocket.close();
} catch (IOException closeException) {}
return;
}
//manageConnectedSocket(mmSocket);
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {}
}
}
// Managing a connection
// Broadcast receiver for connected device
private final BroadcastReceiver connectedReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
showToast("Conneeeeeeeeeeeeected");
}
}
};
// Send data after clicking on a button
private void whiteBtnOn() {
if (mmSocket != null) {
showToast("White btn is clicked");
try {
mmSocket.getOutputStream().write("TO".toString().getBytes());
}
catch (IOException e) {}
}
}
}
}
Thanks in advance for your suggestions!

Try use UUID for Bluetooth SPP:
private final static UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
instead of:
private final static UUID MY_UUID = UUID.fromString("ecff8f1a-ac66-11e6-80f5-76304dec7eb7");

Android bluetooth socket .connect() error

here is my code:
Thread connectThread = new Thread(new Runnable() {
#Override
public void run() {
try {
boolean gotuuid = btDevices.getItem(position)
.fetchUuidsWithSdp();
if (gotuuid){
UUID uuid = btDevices.getItem(position).getUuids()[0]
.getUuid();
mbtSocket = btDevices.getItem(position)
.createRfcommSocketToServiceRecord(uuid);
mbtSocket.connect();
} else {
Log.e("ID22", "There is no uuid");
}
} catch (IOException ex) {
runOnUiThread(socketErrorRunnable);
try {
mbtSocket.close();
} catch (IOException e) {
// e.printStackTrace();
}
mbtSocket = null;
return;
} finally {
runOnUiThread(new Runnable() {
#Override
public void run() {
finish();
}
});
}
}
});
connectThread.start();
}
When I try to use mbtSocket.connect();to connect to the bluetooth soccket it stops and throws socketErrorRunnable exception. Have you got any idea how to fix this? I searched about that but nothing works for me.

In case you have troubles here are some code from the official Android Bluetooth Chat example :
Server side :
public class BluetoothServer {
private final static String TAG = "BluetoothServer";
private final BluetoothServerSocket serverSocket;
// I would recommand defining a secure connexion so forget the unsecore UUID
private static final UUID MY_UUID_SECURE =
UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66"); // choose another UUID go to a site that generates a random UUI ;-)
private static final UUID MY_UUID_INSECURE =
UUID.fromString("8ce255c0-200a-11e0-ac64-0800200c9a66"); // choose another UUID go to a site that generates a random UUI ;-)
// BUT THIS WILL BE THE UUID YOU NEED TO CONNECT TO IN YOUR CLIENT APP -> createRfcommSocketToServiceRecord(UUID.fromString("0800200c9a66"));
// Name for the SDP record when creating server socket
private static final String NAME_SECURE = "BluetoothChatSecure";
private static final String NAME_INSECURE = "BluetoothChatInsecure";
public BluetoothServer(BluetoothAdapter adapter, boolean secure) {
try {
if (secure) {
this.serverSocket = adapter.listenUsingRfcommWithServiceRecord(NAME_SECURE,
MY_UUID_SECURE);
} else {
this.serverSocket = adapter.listenUsingInsecureRfcommWithServiceRecord(
NAME_INSECURE, MY_UUID_INSECURE);
}
} catch (IOException e) {
Log.e(TAG, "Socket Type: " + (secure ? "secure" : "insecure") + "listen() failed", e);
}
}
public void asyncStartServer() {
new Thread(new Runnable() {
#Override
public void run() {
try {
final BluetoothSocket socket = serverSocket.accept(); // blocks/wait until your phone connects
// at this point, your phone is connected
final InputStream is = socket.getInputStream();
// and now start reading
} catch (IOException ioe) {
Log.getStackTraceString(ioe);
}
}
}).start();
}
}

Android bluetooth repeated connections programmatically

I'm trying to get two android phones to connect via bluetooth. I'm following the instructions here from the android online howto's, and I'm following pretty closely.
http://developer.android.com/guide/topics/connectivity/bluetooth.html
I can get bluetooth to connect once, but I have to restart the android device or the app itself in order to get it to connect a second time. This is not a problem during development because with each edit of the code the android studio program re-loads the app. It starts it and restarts it, so that during testing I can connect over and over. During actual use I have to restart the android phone or go to the applications manager option under settings and physically stop that app.
From the code below I can connect if I call these lines:
generateDefaultAdapter();
startDiscovery();
startThreadAccept();
startThreadConnect();
How do I get it so that the bluetooth connection can be initiated over and over again? I see the message 'unable to connect' from the inner class 'ConnectThread' and an IO error from a 'printStackTrace()' from that part of the code. The second time I try, I seem to be able to call the method 'stopConnection()' and then the lines above (starting with 'generateDefaultAdapter()') but I find I cannot connect.
package org.test;
//some import statements here...
public class Bluetooth {
public boolean mDebug = true;
public BluetoothAdapter mBluetoothAdapter;
public UUID mUUID = UUID.fromString(BLUETOOTH_UUID);
public Thread mAcceptThread;
public Thread mConnectThread;
public ConnectedThread mManageConnectionAccept;
public ConnectedThread mManageConnectionConnect;
public APDuellingBluetooth() {
}
public void generateDefaultAdapter() {
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
// Device does not support Bluetooth
}
if (mBluetoothAdapter != null && !mBluetoothAdapter.isEnabled() ) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
(mDialogDuel.getActivity()).startActivityForResult(enableBtIntent, INTENT_ACTIVITY_BLUETOOTH_REQUEST_ENABLE);
}
}
public void cancelDiscovery() { if (mBluetoothAdapter != null) mBluetoothAdapter.cancelDiscovery();}
public void startDiscovery() { mBluetoothAdapter.startDiscovery();}
public BluetoothAdapter getBluetoothAdapter() {return mBluetoothAdapter;}
public void stopConnection () {
try {
if (mAcceptThread != null) {
mAcceptThread.interrupt();
//mAcceptThread.join();
mAcceptThread = null;
}
if (mConnectThread != null) {
mConnectThread.interrupt();
//mConnectThread.join();
mConnectThread = null;
}
if (mManageConnectionConnect != null) {
mManageConnectionConnect.cancel();
mManageConnectionConnect.interrupt();
mManageConnectionConnect = null;
}
if (mManageConnectionAccept != null) {
mManageConnectionAccept.cancel();
mManageConnectionAccept.interrupt();
mManageConnectionAccept = null;
}
}
catch(Exception e) {
e.printStackTrace();
}
}
public void startThreadAccept () {
if (mAcceptThread != null && !mAcceptThread.isInterrupted()) {
if (mDebug) System.out.println("server already open");
//return;
mAcceptThread.interrupt();
mAcceptThread = new AcceptThread();
}
else {
mAcceptThread = new AcceptThread();
}
if (mAcceptThread.getState() == Thread.State.NEW ){
//mAcceptThread.getState() == Thread.State.RUNNABLE) {
mAcceptThread.start();
}
}
public void startThreadConnect () {
BluetoothDevice mDevice = mBluetoothAdapter.getRemoteDevice(mChosen.getAddress());
//if (mDebug) System.out.println(mDevice.getAddress() + " -- " + mChosen.getAddress() );
if (mConnectThread != null && !mConnectThread.isInterrupted()) {
if (mDebug) System.out.println("client already open");
//return;
mConnectThread.interrupt();
mConnectThread = new ConnectThread(mDevice);
}
else {
mConnectThread = new ConnectThread(mDevice);
}
if (mConnectThread.getState() == Thread.State.NEW){// ||
//mConnectThread.getState() == Thread.State.RUNNABLE) {
mConnectThread.start();
}
}
public void manageConnectedSocketAccept(BluetoothSocket socket) {
String mTemp = mBluetoothAdapter.getName();
if (mDebug) {
System.out.println("socket accept from " + mTemp);
System.out.println("info accept " + socket.getRemoteDevice().toString());
}
if (mManageConnectionAccept != null && !mManageConnectionAccept.isInterrupted()) {
//mManageConnectionAccept.cancel();
//mManageConnectionAccept.interrupt();
if (mAcceptThread == null) System.out.println(" bad thread accept");
}
else {
mManageConnectionAccept = new ConnectedThread(socket, "accept");
}
if (mManageConnectionAccept.getState() == Thread.State.NEW ){//||
//mManageConnectionAccept.getState() == Thread.State.RUNNABLE) {
mManageConnectionAccept.start();
}
}
public void manageConnectedSocketConnect(BluetoothSocket socket) {
String mTemp = mBluetoothAdapter.getName();
if (mDebug) {
System.out.println("socket connect from " + mTemp);
System.out.println("info connect " + socket.getRemoteDevice().toString());
}
if (mManageConnectionConnect != null && !mManageConnectionConnect.isInterrupted()) {
//mManageConnectionConnect.cancel();
//mManageConnectionConnect.interrupt();
if (mConnectThread == null) System.out.print(" bad thread connect ");
}
else {
mManageConnectionConnect = new ConnectedThread(socket, "connect");
}
if (mManageConnectionConnect.getState() == Thread.State.NEW){// ||
//mManageConnectionConnect.getState() == Thread.State.RUNNABLE) {
mManageConnectionConnect.start();
}
}
public void decodeInput (String mIn, ConnectedThread mSource) {
// do something with info that is returned to me...
}
public void encodeOutput (String mMac1, String mMac2, int mLR1, int mLR2) {
String mTemp = composeOutputString ( mServer, mMac1,mMac2, mLR1, mLR2);
if (mManageConnectionConnect != null && mManageConnectionConnect.isConnected()) {
mManageConnectionConnect.write(mTemp.getBytes());
mManageConnectionConnect.flush();
}
if (mManageConnectionAccept != null && mManageConnectionAccept.isConnected()) {
mManageConnectionAccept.write(mTemp.getBytes());
mManageConnectionAccept.flush();
}
mTemp = composeOutputString ( mClient, mMac1,mMac2, mLR1, mLR2);
if (mManageConnectionConnect != null && mManageConnectionConnect.isConnected()) {
mManageConnectionConnect.write(mTemp.getBytes());
mManageConnectionConnect.flush();
}
if (mManageConnectionAccept != null && mManageConnectionAccept.isConnected()) {
mManageConnectionAccept.write(mTemp.getBytes());
mManageConnectionAccept.flush();
}
}
public String composeOutputString (SocketConnectData mData, String mMac1, String mMac2, int mLR1, int mLR2) {
// make a string here with the data I want to send...
String mTemp = new String();
return mTemp;
}
/////////////////////////////////////////////
private class AcceptThread extends Thread {
private final BluetoothServerSocket mmServerSocket;
private boolean mLoop = true;
public AcceptThread() {
// Use a temporary object that is later assigned to mmServerSocket,
// because mmServerSocket is final
mLoop = true;
BluetoothServerSocket tmp = null;
try {
// MY_UUID is the app's UUID string, also used by the client code
tmp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(mServiceNameReceive, mUUID );
} catch (IOException e) {
System.out.println("rfcomm problem ");
}
mmServerSocket = tmp;
}
public void run() {
BluetoothSocket socket = null;
// Keep listening until exception occurs or a socket is returned
while (mLoop) {
try {
if (mmServerSocket != null) {
socket = mmServerSocket.accept();
}
} catch (IOException e) {
if (mDebug) System.out.println("rfcomm accept problem");
e.printStackTrace();
break;
}
// If a connection was accepted
if (socket != null && ! isConnectionOpen() ) {
// Do work to manage the connection (in a separate thread)
manageConnectedSocketAccept(socket);
try {
mmServerSocket.close();
}
catch (IOException e) {}
break;
}
}
}
/** Will cancel the listening socket, and cause the thread to finish */
public void cancel() {
try {
mLoop = false;
mmServerSocket.close();
} catch (IOException e) { }
}
}
/////////////////////////////////////////////
private class ConnectThread extends Thread {
//private final BluetoothSocket mmSocket;
private BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to mmSocket,
// because mmSocket is final
BluetoothSocket tmp = null;
mmDevice = device;
try {
tmp = device.createRfcommSocketToServiceRecord(mUUID);
if (mDebug) System.out.println("connect -- rf socket to service record " + tmp);
} catch (Exception e) {
System.out.println("exception -- rf socket to service record problem " + tmp);
}
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it will slow down the connection
mBluetoothAdapter.cancelDiscovery();
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mmSocket.connect();
}
//catch (InterruptedException e ) {System.out.println("interrupted exception");}
catch (IOException e) {
// Unable to connect; close the socket and get out
if (mDebug) System.out.println("unable to connect ");
e.printStackTrace(); // <---- I see output from this spot!!
try {
mmSocket.close();
} catch (IOException closeException) {
System.out.println("unable to close connection ");
}
return;
}
// Do work to manage the connection (in a separate thread)
if (mmSocket.isConnected() && ! isConnectionOpen()) {
manageConnectedSocketConnect(mmSocket);
}
}
/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
public boolean isConnected() {
return mmSocket.isConnected();
}
}
/////////////////////////////////////////////
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public String mTypeName = "";
private boolean mLoop = true;
public StringWriter writer;
public ConnectedThread(BluetoothSocket socket, String type) {
mTypeName = type;
mLoop = true;
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
try {
writer = new StringWriter();
}
catch (Exception e) {}
}
public void run() {
byte[] buffer = new byte[1024]; //
int bytes; // bytes returned from read()
String [] mLines ;
// Keep listening to the InputStream until an exception occurs
while (mLoop) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
if (bytes == -1 || bytes == 0) {
if (mDebug) System.out.println("zero read");
return;
}
writer.append(new String(buffer, 0, bytes));
mLines = writer.toString().split("!");
if (mDebug) System.out.println( "lines " +mLines.length);
for (int i = 0; i < mLines.length; i ++ ) {
if (true) {
if (mDebug) System.out.println(" " + mLines[i]);
decodeInput (mLines[i], this);
}
}
} catch (Exception e) {
e.printStackTrace();
if (mDebug) System.out.println("read buffer problem");
break;
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
mmOutStream.write(bytes);
} catch (IOException e) {
e.printStackTrace();
if (mDebug) System.out.println("bad write");
}
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mLoop = false;
mmSocket.close();
mmOutStream.close();
mmInStream.close();
} catch (IOException e) { }
}
public boolean isConnected() {
boolean mIsOpen = false;
try {
mIsOpen = mmSocket.isConnected() ;
} catch (Exception e) {}
return mIsOpen;
}
public void flush() {
try {
mmOutStream.flush();
}
catch (IOException e) {e.printStackTrace();}
}
}
///////////////////////////////////////////////
}
Thanks for your time.
EDIT: this is the error msg:
W/System.err﹕ java.io.IOException: read failed, socket might closed or timeout, read ret: -1
W/System.err﹕ at android.bluetooth.BluetoothSocket.readAll(BluetoothSocket.java:553)
W/System.err﹕ at android.bluetooth.BluetoothSocket.waitSocketSignal(BluetoothSocket.java:530)
W/System.err﹕ at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:357)
W/System.err﹕ at org.davidliebman.test.Bluetooth$ConnectThread.run(Bluetooth.java:761)

Try this:
Instead of restarting the app. Turn off the Bluetooth on the Android device and turn it back on after a 5-sec delay. If you could make the connection successfully, it typically a sign that you did not close the connection and socket completely. Log your code. Make sure the closing socket routine is smoothly executed. Check if the IOException you have in your cancel method of your ConnectedThread is not catching any exception:
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
// ADD LOG
mLoop = false;
mmSocket.close();
mmOutStream.close();
mmInStream.close();
// ADD LOG
} catch (IOException e) {
// ADD LOG}
}