Develop Reference

Trying to use bluetooth, but lack understanding of handler

my last question was closed because not focused enough. My goal is to send an array to a Bluetooth module hc-06 to pilot an Arduino. I have made research and visited this page (among many other):Android sample bluetooth code to send a simple string via bluetooth
I would be interested in an explanation to make the following code work:
import android.annotation.SuppressLint;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Set;
import java.util.UUID;
public class multiplayerConnect extends AppCompatActivity {
public static final int REQUEST_ENABLE_BT=1;
ListView lv_paired_devices;
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);
//do some task based on received string
break;
case MESSAGE_WRITE:
if(msg_type.obj!=null){
ConnectedThread connectedThread=new ConnectedThread((BluetoothSocket)msg_type.obj);
connectedThread.write(bluetooth_message.getBytes());
}
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(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.multiplayer_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);
}
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();
} catch (IOException e) {
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) { }
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
}
I tried to add a button on my end to use the "write" function. However, as it belongs to the ConnectedThread class, I can't use it directly. So I tried to use the handler, but apparently, the message I made has an obj=null. I read the documentation about the "messages" but I did not manage to resolve the problem. There are no errors until I try to add the obj in which case the code doesn't compile. When i removed the if (message_type.obj != null) my application just stopped.
To summarize: I want to send data via Bluetooth. I made my research, but I need a helping hand to use the handler.

W/libEGL: EGLNativeWindowType 0x7d358f1010 disconnect failed

package com.example.yj.bluetoothapplication;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.util.UUID;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.graphics.Color;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final String TAG = "bluetooth2";
Button btnLed1, btnLed2, btnLed3, btnpado;
TextView txtArduino;
RelativeLayout rlayout;
Handler h;
final int RECIEVE_MESSAGE = 1; // Status for Handler
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private StringBuilder sb = new StringBuilder();
private static int flag = 0;
private ConnectedThread mConnectedThread;
// SPP UUID service
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// MAC-address of Bluetooth module (you must edit this line)
private static String address = "98:D3:61:FD:59:9D";
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnLed1 = (Button) findViewById(R.id.btnLed1);
btnLed2 = (Button) findViewById(R.id.btnLed2);
btnLed3 = (Button) findViewById(R.id.btnLed3);
btnpado = (Button) findViewById(R.id.btnPado);
txtArduino = (TextView) findViewById(R.id.txtArduino);
rlayout = (RelativeLayout) findViewById(R.id.layout);
h = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case RECIEVE_MESSAGE:
byte[] readBuf = (byte[]) msg.obj;
String strIncom = new String(readBuf, 0, msg.arg1);
sb.append(strIncom);
int endOfLineIndex = sb.indexOf("\r\n");
if (endOfLineIndex > 0) {
String sbprint = sb.substring(0, endOfLineIndex);
sb.delete(0, sb.length());
txtArduino.setText("Data from Arduino: " + sbprint);
if(flag%4==3){
rlayout.setBackgroundColor(Color.rgb(255, 255, 255));
}
else if(flag%4==1){
rlayout.setBackgroundColor(Color.rgb(255, 0, 0));
}
else if(flag%4==2){
rlayout.setBackgroundColor(Color.rgb(0, 255, 0));
}
else if(flag%4==0){
rlayout.setBackgroundColor(Color.rgb(0, 0, 255));
}
flag++;
btnLed1.setEnabled(true);
btnLed2.setEnabled(true);
btnLed3.setEnabled(true);
btnpado.setEnabled(true);
}
break;
}
};
};
btAdapter = BluetoothAdapter.getDefaultAdapter(); // get Bluetooth adapter
checkBTState();
btnLed1.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
mConnectedThread.write("1");
Toast.makeText(getBaseContext(), "Turn on First LED", Toast.LENGTH_SHORT).show();
}
});
btnLed2.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
mConnectedThread.write("2");
//Toast.makeText(getBaseContext(), "Turn on Second LED", Toast.LENGTH_SHORT).show();
}
});
btnLed3.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
mConnectedThread.write("3");
//Toast.makeText(getBaseContext(), "Turn on Third LED", Toast.LENGTH_SHORT).show();
}
});
btnpado.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
mConnectedThread.write("0");
//Toast.makeText(getBaseContext(), "Turn on all LEDs", Toast.LENGTH_SHORT).show();
}
});
}
private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {
if(Build.VERSION.SDK_INT >= 10){
try {
final Method m = device.getClass().getMethod("createInsecureRfcommSocketToServiceRecord", new Class[] { UUID.class });
return (BluetoothSocket) m.invoke(device, MY_UUID);
} catch (Exception e) {
Log.e(TAG, "Could not create Insecure RFComm Connection",e);
}
}
return device.createRfcommSocketToServiceRecord(MY_UUID);
}
#Override
public void onResume() {
super.onResume();
Log.d(TAG, "...onResume - try connect...");
// Set up a pointer to the remote node using it's address.
BluetoothDevice device = btAdapter.getRemoteDevice(address);
// Two things are needed to make a connection:
// A MAC address, which we got above.
// A Service ID or UUID. In this case we are using the
// UUID for SPP.
try {
btSocket = createBluetoothSocket(device);
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
}
// Discovery is resource intensive. Make sure it isn't going on
// when you attempt to connect and pass your message.
btAdapter.cancelDiscovery();
// Establish the connection. This will block until it connects.
Log.d(TAG, "...Connecting...");
try {
btSocket.connect();
Log.d(TAG, "....Connection ok...");
} catch (IOException e) {
try {
btSocket.close();
} catch (IOException e2) {
errorExit("Fatal Error", "In onResume() and unable to close socket during connection failure" + e2.getMessage() + ".");
}
}
// Create a data stream so we can talk to server.
Log.d(TAG, "...Create Socket...");
mConnectedThread = new ConnectedThread(btSocket);
mConnectedThread.start();
}
#Override
public void onPause() {
super.onPause();
Log.d(TAG, "...In onPause()...");
try {
btSocket.close();
} catch (IOException e2) {
errorExit("Fatal Error", "In onPause() and failed to close socket." + e2.getMessage() + ".");
}
}
private void checkBTState() {
// Check for Bluetooth support and then check to make sure it is turned on
// Emulator doesn't support Bluetooth and will return null
if(btAdapter==null) {
errorExit("Fatal Error", "Bluetooth not support");
} else {
if (btAdapter.isEnabled()) {
Log.d(TAG, "...Bluetooth ON...");
} else {
//Prompt user to turn on Bluetooth
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
}
}
}
private void errorExit(String title, String message){
Toast.makeText(getBaseContext(), title + " - " + message, Toast.LENGTH_LONG).show();
finish();
}
private class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket 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[256]; // 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); // Get number of bytes and message in "buffer"
h.obtainMessage(RECIEVE_MESSAGE, bytes, -1, buffer).sendToTarget(); // Send to message queue Handler
} catch (IOException e) {
break;
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(String message) {
Log.d(TAG, "...Data to send: " + message + "...");
byte[] msgBuffer = message.getBytes();
try {
mmOutStream.write(msgBuffer);
} catch (IOException e) {
Log.d(TAG, "...Error data send: " + e.getMessage() + "...");
}
}
}
D/BluetoothSocket: close() this: android.bluetooth.BluetoothSocket#d1bd8ab, channel: 1, mSocketIS: android.net.LocalSocketImpl$SocketInputStream#218b08, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream#6d4d2a1mSocket: android.net.LocalSocket#a50ecc6 impl:android.net.LocalSocketImpl#3bd5487 fd:java.io.FileDescriptor#ec84fb4, mSocketState: CONNECTED D/ViewRootImpl#3a2e96b[MainActivity]: MSG_WINDOW_FOCUS_CHANGED 0 1 D/InputMethodManager: prepareNavigationBarInfo() DecorView#a62bffa[MainActivity] getNavigationBarColor() -855310 D/InputTransport: Input channel destroyed: fd=76 W/libEGL: EGLNativeWindowType 0x7d358f2010 disconnect failed D/OpenGLRenderer: eglDestroySurface = 0x7d1f6ac180, 0x7d358f2000 D/ViewRootImpl#3a2e96b[MainActivity]: Relayout returned: old=[0,0][1080,2280] new=[0,0][1080,2280] result=0x5 surface={valid=false 0} changed=true D/ViewRootImpl#3a2e96b[MainActivity]: setWindowStopped(true) old=false D/ViewRootImpl#3a2e96b[MainActivity]: Surface release. android.view.WindowManagerGlobal.setStoppedState:669 android.app.Activity.performStop:7647 android.app.ActivityThread.callActivityOnStop:4378 android.app.ActivityThread.performStopActivityInner:4356 android.app.ActivityThread.handleStopActivity:4431 android.app.servertransaction.StopActivityItem.execute:41 android.app.servertransaction.TransactionExecutor.executeLifecycleState:145 android.app.servertransaction.TransactionExecutor.execute:70 D/BluetoothSocket: close() this: android.bluetooth.BluetoothSocket#f21e178, channel: 1, mSocketIS: android.net.LocalSocketImpl$SocketInputStream#eefc051, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream#853c0b6mSocket: null, mSocketState: CLOSED Process 30538 terminated.

Android Studio - Issue connecting with device resulting in the socket getting closed

I am attempting to create an android app that connects to an Bluetooth device and am struggling with connecting.When running the run() method when I try to connect it does not work and goes to the catch portion of the code giving me the output of "socket closed". i am not sure why the try is not working.
I am aware that my code has several flaws, i am on my 5th day of android developing, however any help I could get would be greatly appreciated. The big problem I need to fix is being able to connect to the device and ultimately being able to receive a stream of data from it.
public class BluetoothConnection extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
byte[] buffer;
BluetoothAdapter mmAdapter;
// Unique UUID for this application, you may use different
private static final UUID MY_UUID = UUID
.fromString("eb58f747-a241-4ccb-935d-04ac6039895d");
public BluetoothConnection(BluetoothDevice device) {
BluetoothSocket tmp = null;
mmAdapter = null;
System.out.println("\n\n\n\n\n\n print is working? \n\n\n\n\n\n");
// Get a BluetoothSocket for a connection with the given BluetoothDevice
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
e.printStackTrace();
}
mmSocket = tmp;
//now make the socket connection in separate thread to avoid FC
Thread connectionThread = new Thread(new Runnable() {
#Override
public void run() {
// Always cancel discovery because it will slow down a connection
Log.d("workkkkkk","$$$$$$$$$$$$$$$$****** printingggggg ******$$$$$$$$$$$$$$$$");
//mmAdapter.cancelDiscovery();
}
});
connectionThread.start();
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
try {
// This is a blocking call and will only return on a
// successful connection or an exception
mmSocket.connect();
System.out.println("\n\n\n\n\n\n socket connected\n\n\n\n\n\n");
} catch (IOException e) {
//connection to device failed so close the socket
try {
mmSocket.close();
System.out.println("\n\n\n\n\n\n socket closed\n\n\n\n\n\n");
} catch (IOException e2) {
System.out.println("\n\n\n\n\n\n in catch\n\n\n\n\n\n");
e2.printStackTrace();
}
}
tmpIn = mmSocket.getInputStream();
tmpOut = mmSocket.getOutputStream();
buffer = new byte[1024];
} catch (IOException e) {
e.printStackTrace();
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
// Keep listening to the InputStream while connected
while (true) {
try {
//read the data from socket stream
if(mmInStream != null) {
mmInStream.read(buffer);
}
// Send the obtained bytes to the UI Activity
} catch (IOException e) {
//an exception here marks connection loss
//send message to UI Activity
break;
}
}
}
public void write(byte[] buffer) {
try {
//write the data to socket stream
if(mmOutStream != null)
mmOutStream.write(buffer);
} catch (IOException e) {
e.printStackTrace();
}
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
This is being run in my DeviceList Class which is here. I am running into multiple problems here but the big one is pertaining to the BluetoothConnection.java however i am not sure if the issue is happening because of this class.
package com.example.curie.fairbanks_01;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothSocket;
import android.app.Activity;
import android.os.Bundle;
import java.io.IOException;
import android.util.Log;
import android.view.View;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.PopupMenu;
import android.widget.Switch;
import android.widget.Toast;
import android.content.Intent;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Set;
import java.util.UUID;
public class DeviceList extends Activity {
Button deviceSearch;
Switch btSwitch;
private BluetoothAdapter BA;
private Set<BluetoothDevice>pairedDevices;
private String instrumentName;
private UUID instrumentUUID;
BluetoothSocket socket;
BluetoothConnection connector;
ListView lv;
public static BluetoothDevice instrument;
PopupMenu pMenu;
ArrayList<MenuItem> popupList;
ArrayList<BluetoothDevice> list;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_device_list);
deviceSearch = (Button) findViewById(R.id.device_search);
deviceSearch.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
PopupMenu popup = new PopupMenu(DeviceList.this, findViewById(R.id.device_search));
pairedDevices = BA.getBondedDevices();
list = new ArrayList<BluetoothDevice>();
for (BluetoothDevice bt : pairedDevices) {
list.add(bt);
popup.getMenu().add(bt.getName());
popup.show();
}
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
public boolean onMenuItemClick(MenuItem item) {
ArrayList<BluetoothDevice> deviceArrayList = new ArrayList<BluetoothDevice>(pairedDevices);
Toast.makeText(DeviceList.this, "Testing: " + item.getTitle(), Toast.LENGTH_SHORT).show();
// instrument = deviceArrayList.get(deviceArrayList.indexOf(item.getItemId()));
instrument = deviceArrayList.get(0);
connector = new BluetoothConnection(instrument);
connector.run();
Toast.makeText(DeviceList.this, "Connected to : " + item.getTitle(), Toast.LENGTH_SHORT).show();
Intent myIntent = new Intent(DeviceList.this, InputActivity.class);
DeviceList.this.startActivity(myIntent);
return true;
}
});
}
});
btSwitch = (Switch) findViewById(R.id.switch1);
BA =BluetoothAdapter.getDefaultAdapter();
lv =(ListView) findViewById(R.id.listView);
if(BA.isEnabled())
btSwitch.setChecked(true);
else
btSwitch.setChecked(false);
// pMenu = new PopupMenu(this,findViewById(R.id.device_search));
}
public void list(View v){
// pairedDevices = BA.getBondedDevices();
//
// ArrayList list = new ArrayList();
//
// for(BluetoothDevice bt : pairedDevices){
//
// list.add(bt.getName());
// pMenu.getMenu().add(bt.toString());
// }
Toast.makeText(getApplicationContext(), "Showing Paired Devices",Toast.LENGTH_SHORT).show();
final ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_1, list);
lv.setAdapter(adapter);
}
public void onOff(View v)
{
if(BA.isEnabled())
{
BA.disable();
Toast.makeText(getApplicationContext(), " BT Turned off" ,Toast.LENGTH_LONG).show();
}
else
{ BA.enable();
Toast.makeText(getApplicationContext(), "BT Turned on" ,Toast.LENGTH_LONG).show();
}
}
public static BluetoothDevice getInstrument() {
return instrument;
}
}
this is what is running on the console when I select the device I would like to connect to:
I/System.out: $$$$$$$$$$$$$$$$****** in constructor ******$$$$$$$$$$$$$$$$
D/workkkkkk: $$$$$$$$$$$$$$$$****** printingggggg ******$$$$$$$$$$$$$$$$
D/BluetoothUtils: isSocketAllowedBySecurityPolicy start : device null
D/BluetoothSocket: connect(): myUserId = 0
W/BluetoothAdapter: getBluetoothService() called with no BluetoothManagerCallback
I/System.out: $$$$$$$$$$$$$$$$****** socket closed ******$$$$$$$$$$$$$$$$
D/BluetoothSocket: getInputStream(): myUserId = 0
getOutputStream(): myUserId = 0
Why is it not connecting in the try?

Manage Bluetooth Communication

Im actually trying to interact with a bluetooth module controlled by a microcontroller PIC.
So i need to build an android app in order to send caracters by bluetooth.
But im kind of lost.
The beginning is quiet clear to me ( enabling bluetooth and connect as client)
But i dont know how to interact with my Bluetooth Service class from my MainActivity.
How to interact with write and read.
I can see that im successfully Connected to my device.
ALEA is the name of the BT module i want to connect to.
Thanks for your help
package com.example.stef.bluetoothencore;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.ListView;
import android.widget.Toast;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Set;
import java.util.UUID;
public class MainActivity extends AppCompatActivity {
private BluetoothAdapter mBluetoothAdapter;
ArrayList<BluetoothDevice> arrayListBluetoothDevices = null;
ArrayList<String> NomBT=null;
BluetoothDevice mydevice;
int position_alea=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView lv=(ListView)findViewById(R.id.listdevice);
CheckBox Aleabox=(CheckBox) findViewById(R.id.checkAlea);
arrayListBluetoothDevices = new ArrayList<BluetoothDevice>();
NomBT= new ArrayList<String>();
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
// Device does not support Bluetooth
}
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
}
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
for (BluetoothDevice device : pairedDevices) {
BluetoothDevice mDevice = device;
arrayListBluetoothDevices.add(device); // On charge la liste de Device
NomBT.add(device.getName().toString());
if(device.getName().toString().equals("ALEA")){
mydevice=device;
Aleabox.setChecked(true);
Aleabox.setText(mydevice.getName().toString());
}
}
}
final ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, NomBT);
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
// position_alea=i;
//Toast.makeText(getApplicationContext(), mydevice.getName().toString(), Toast.LENGTH_SHORT).show();
ConnectThread mConnectThread = new ConnectThread(mydevice);
mConnectThread.start();
}
});
}
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
private final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
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;
}
ConnectedThread mConnectedThread = new ConnectedThread(mmSocket);
mConnectedThread.start();
mConnectedThread.write("c".getBytes());
}
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;
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[1024];
int begin = 0;
int bytes = 0;
while (true) {
try {
bytes += mmInStream.read(buffer, bytes, buffer.length - bytes);
for(int i = begin; i < bytes; i++) {
if(buffer[i] == "#".getBytes()[0]) {
mHandler.obtainMessage(1, begin, i, buffer).sendToTarget();
begin = i + 1;
if(i == bytes - 1) {
bytes = 0;
begin = 0;
}
}
}
} catch (IOException e) {
break;
}
}
}
public void write(byte[] bytes) {
try {
mmOutStream.write(bytes);
} catch (IOException e) { }
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
Handler mHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
byte[] writeBuf = (byte[]) msg.obj;
int begin = (int)msg.arg1;
int end = (int)msg.arg2;
switch(msg.what) {
case 1:
String writeMessage = new String(writeBuf);
writeMessage = writeMessage.substring(begin, end);
break;
}
}
};
}

Up, im still blocked, i am connected to my device but i can't read or write data ...

I can't send the data through Bluetooth

I wrote the application in Android Studio which has to send 1 on Arduino Pro Mini. Data is sent but doesn't reach Arduino. I checked Arduino through Bluetooth Terminal and everything was OK so the problem is in code. What is wrong?
package com.example.niko.motoco;
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.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.io.IOException;
import java.io.OutputStream;
import java.util.UUID;
public class MainActivity extends AppCompatActivity {
BluetoothAdapter btAdapter = null ;
BluetoothDevice btDevice = null;
BluetoothSocket btSocket = null;
final String LOG_TAG = "myLogs";
Button btConnect, btSend;
public TextView checkText;
private static final int REQUEST_ENABLE_BT = 1;
private static final int CONNECTEDdevice = 2;
Boolean connection = false;
private static String MAC = null;
UUID my_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
private ConnectedThread MyThread = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
checkText = (TextView) findViewById(R.id.checkText);
btConnect = (Button)findViewById(R.id.btConnect);
btSend = (Button)findViewById(R.id.btSend);
btAdapter = BluetoothAdapter.getDefaultAdapter();
if (btAdapter == null) {
Toast.makeText(getApplicationContext(),"Device does not support Bluetooth",Toast.LENGTH_LONG).show();
} else if (!btAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
btConnect.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (connection) {
// disconnect
try {
btSocket.close();
connection = false;
btConnect.setText("Connect");
Toast.makeText(getApplicationContext(),"Bluetooht is disconnected:",Toast.LENGTH_LONG).show();
} catch (IOException error) {
Toast.makeText(getApplicationContext(),"Error;" + error,Toast.LENGTH_LONG).show();
}
} else {
// connect
Intent ListDevices = new Intent(MainActivity.this, ListDevices.class);
startActivityForResult(ListDevices,CONNECTEDdevice);
}
}
});
btSend.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
MyThread.write((byte) 1);
Toast.makeText(getApplicationContext(),"Sending 1",Toast.LENGTH_LONG).show();
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
//super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case REQUEST_ENABLE_BT:
if(resultCode == Activity.RESULT_OK) {
Toast.makeText(getApplicationContext(),"bluetooth is activated",Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(),"bluetooth is not activated",Toast.LENGTH_LONG).show();
finish();
}
break;
case CONNECTEDdevice :
if (resultCode == Activity.RESULT_OK) {
MAC = data.getExtras().getString(ListDevices.MACaddress);
btDevice = btAdapter.getRemoteDevice(MAC);
try {
btSocket = btDevice.createRfcommSocketToServiceRecord(my_UUID);
btSocket.connect();
connection = true;
btConnect.setText("Disconnect");
Toast.makeText(getApplicationContext(),"MAC of connected device:" + MAC,Toast.LENGTH_LONG).show();
MyThread = new ConnectedThread(btSocket);
//MyThread.start();
} catch (IOException error) {
connection = false;
Toast.makeText(getApplicationContext(),"Error:" + error,Toast.LENGTH_LONG).show();
}
}else {
Toast.makeText(getApplicationContext(),"didn't get MAC",Toast.LENGTH_LONG).show();
}
}
}
private class ConnectedThread extends Thread {
private final BluetoothSocket btSocket2;
private final OutputStream OutStream;
public ConnectedThread(BluetoothSocket socket) {
btSocket2 = socket;
OutputStream tmpOut = null;
try {
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
OutStream = tmpOut;
}
public void write(byte bytes) {
try {
OutStream.write(bytes);
} catch (IOException e) { }
}
public void cancel() {
try {
btSocket2.close();
} catch (IOException e) { }
}
}
}

What's wrong ? At least those 2 pieces of code are wrong :
try {
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
And later:
try {
OutStream.write(bytes);
} catch (IOException e) { }
When something goes wrong you catch the exception silently and loose all chances to identify the root cause.
Change the code to something like this :
try {
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Log.(TAG, "Fail to get socket output stream" ,e);
}
And later :
try {
OutStream.write(bytes);
} catch (IOException e) {
Log.(TAG, "Fail to write on socket output stream" ,e);
}
Then re-run your code and look at the logcat. You will probably see the cause of your problems.