Develop Reference

Android Studio Bluetooth ListView

I wanted to make bluetooth applications for arduino so that I could connect to the HC-05 module. And I found a tutorial on how to make a bluetooth connection (http://mcuhq.com/27/simple-android-bluetooth-application-with-arduino-example) When I downloaded the code from github, the application starts and everything works and connects. But the problem is that I can't open a new activity because the project is probably for 15 API and the new activity needs at least 16 so I decided to make such an application on my own based on the code from this website. And here I have a problem because when I make my phone search for bluetooth devices, nothing is displayed on my ListView.
This is my code `
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
offon = findViewById(R.id.BtBtn);
TV = findViewById(R.id.BtTv);
TV2 = findViewById(R.id.textView2);
TV3 = findViewById(R.id.bluetooth_status);
Next = findViewById(R.id.button2);
LV = findViewById(R.id.ListView);
disc = findViewById(R.id.button3);
ArrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
adapter = BluetoothAdapter.getDefaultAdapter();
LV.setAdapter(ArrayAdapter);
LV.setOnItemClickListener(DeviceList);
handler = new Handler(Looper.getMainLooper()){
#Override
public void handleMessage(Message msg){
if(msg.what == MESSAGE_READ){
String readMessage = null;
readMessage = new String((byte[]) msg.obj, StandardCharsets.UTF_8);
TV2.setText(readMessage);
}
if(msg.what == CONNECTING_STATUS){
char[] sConnected;
if(msg.arg1 == 1)
TV3.setText(getString(R.string.BTConnected) + msg.obj);
else
TV3.setText(getString(R.string.BTconnFail));
}
}
};
if (adapter.isEnabled()){
TV.setText("Bluetooth ON");
}else TV.setText("Bluetooth OFF");
disc.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
discovery();
if (!adapter.isEnabled()){
Toast.makeText(getBaseContext(), getString(R.string.BTnotOn), Toast.LENGTH_SHORT).show();
}
}
});
offon.setOnClickListener(new View.OnClickListener() {
#SuppressLint("MissingPermission")
#Override
public void onClick(View view) {
if (adapter.isEnabled()) {
adapter.disable();
TV.setText("Bluetooth OFF");
}else {
adapter.enable();
TV.setText("Bluetooth ON");
}
}
});
Next.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
open2activity();
}
});
}
public void open2activity(){
Intent intent = new Intent(this, MainActivity2.class);
startActivity(intent);
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent Data) {
super.onActivityResult(requestCode, resultCode, Data);
}
#SuppressLint("MissingPermission")
private void discovery(){
if (adapter.isDiscovering()){
adapter.cancelDiscovery();
Toast.makeText(getApplicationContext(), getString(R.string.DisStop), Toast.LENGTH_SHORT).show();
}
else{
if (adapter.isEnabled()){
ArrayAdapter.clear();
adapter.startDiscovery();
Toast.makeText(getApplicationContext(), getString(R.string.DisStart), Toast.LENGTH_SHORT).show();
registerReceiver(blReceiver, new IntentFilter(BluetoothDevice.ACTION_FOUND));
}
}
}
final BroadcastReceiver blReceiver = new BroadcastReceiver() {
#SuppressLint("MissingPermission")
#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);
ArrayAdapter.add(device.getName() + "\n" + device.getAddress());
ArrayAdapter.notifyDataSetChanged();
}
}
};
private AdapterView.OnItemClickListener DeviceList = new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
TV3.setText(getString(R.string.cConnet));
String info = ((TextView)view).getText().toString();
final String address = info.substring(info.length() - 17);
final String name = info.substring(0,info.length() - 17);
new Thread()
{
#SuppressLint("MissingPermission")
#Override
public void run() {
boolean fail = false;
BluetoothDevice device = adapter.getRemoteDevice(address);
try {
BTSocket = createBluetoothSocket(device);
} catch (IOException e) {
fail = true;
Toast.makeText(getBaseContext(), getString(R.string.ErrSockCrea), Toast.LENGTH_SHORT).show();
}
try {
BTSocket.connect();
} catch (IOException e) {
try {
fail = true;
BTSocket.close();
handler.obtainMessage(CONNECTING_STATUS, -1, -1)
.sendToTarget();
} catch (IOException e2) {
Toast.makeText(getBaseContext(), getString(ErrSockCrea), Toast.LENGTH_SHORT).show();
}
}
if(!fail) {
ConnectedThread = new ConnectedThread(BTSocket, handler);
ConnectedThread.start();
handler.obtainMessage(CONNECTING_STATUS, 1, -1, name)
.sendToTarget();
}
}
}.start();
}
};
#SuppressLint("MissingPermission")
private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {
try {
final Method m = device.getClass().getMethod("createInsecureRfcommSocketToServiceRecord", UUID.class);
return (BluetoothSocket) m.invoke(device, BT_MODULE_UUID);
} catch (Exception e) {
Log.e(TAG, "Could not create Insecure RFComm Connection",e);
}
return device.createRfcommSocketToServiceRecord(BT_MODULE_UUID);
}
}
`
I tried to do as above but nothing is displayed

Bluetooth Connection

I've looked at quite a lot of topics on this in different forums and none seem to help me.
I recently bought an Elegoo car kit, which is compatible with the Arduino IDE, and it comes with different types of code and what not. they even have their own Android app.
My problem is I want to create my own android Bluetooth application that connects/pairs with the module and can control the car remotely. I have my application up and running, it can scan for nearby devices and the HC-08 module appears in the list but I am not able to connect. when I try to connect it says it can't communicate with HC-08. I am pretty sure the problem lies in the android end as the elegoo Bluetooth app connects no problem at all with the Bluetooth module if there is any code on the elegoo board or not. The bluetooth module is a HC-08.
Can someone help me with this ?
Also I am following this youtube tutorial so the credit goes to him for the code.
https://www.youtube.com/watch?v=YJ0JQXcNNTA
Here is the main activity code:
public class MainActivity extends AppCompatActivity implements
AdapterView.OnItemClickListener{
private static final String TAG = "MainActivity";
BluetoothAdapter mBluetoothAdapter;
Button btnEnableDisable_Discoverable;
public ArrayList<BluetoothDevice> mBTDevices = new ArrayList<>();
public DeviceListAdapter mDeviceListAdapter;
ListView lvNewDevices;
// Create a BroadcastReceiver for ACTION_FOUND
private final BroadcastReceiver mBroadcastReceiver1 = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// When discovery finds a device
if (action.equals(mBluetoothAdapter.ACTION_STATE_CHANGED)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, mBluetoothAdapter.ERROR);
switch(state){
case BluetoothAdapter.STATE_OFF:
Log.d(TAG, "onReceive: STATE OFF");
break;
case BluetoothAdapter.STATE_TURNING_OFF:
Log.d(TAG, "mBroadcastReceiver1: STATE TURNING OFF");
break;
case BluetoothAdapter.STATE_ON:
Log.d(TAG, "mBroadcastReceiver1: STATE ON");
break;
case BluetoothAdapter.STATE_TURNING_ON:
Log.d(TAG, "mBroadcastReceiver1: STATE TURNING ON");
break;
}
}
}
};
/**
* Broadcast Receiver for changes made to bluetooth states such as:
* 1) Discoverability mode on/off or expire.
*/
private final BroadcastReceiver mBroadcastReceiver2 = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED)) {
int mode = intent.getIntExtra(BluetoothAdapter.EXTRA_SCAN_MODE, BluetoothAdapter.ERROR);
switch (mode) {
//Device is in Discoverable Mode
case BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE:
Log.d(TAG, "mBroadcastReceiver2: Discoverability Enabled.");
break;
//Device not in discoverable mode
case BluetoothAdapter.SCAN_MODE_CONNECTABLE:
Log.d(TAG, "mBroadcastReceiver2: Discoverability Disabled. Able to receive connections.");
break;
case BluetoothAdapter.SCAN_MODE_NONE:
Log.d(TAG, "mBroadcastReceiver2: Discoverability Disabled. Not able to receive connections.");
break;
case BluetoothAdapter.STATE_CONNECTING:
Log.d(TAG, "mBroadcastReceiver2: Connecting....");
break;
case BluetoothAdapter.STATE_CONNECTED:
Log.d(TAG, "mBroadcastReceiver2: Connected.");
break;
}
}
}
};
/**
* Broadcast Receiver for listing devices that are not yet paired
* -Executed by btnDiscover() method.
*/
private BroadcastReceiver mBroadcastReceiver3 = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
Log.d(TAG, "onReceive: ACTION FOUND.");
if (action.equals(BluetoothDevice.ACTION_FOUND)){
BluetoothDevice device = intent.getParcelableExtra (BluetoothDevice.EXTRA_DEVICE);
mBTDevices.add(device);
Log.d(TAG, "onReceive: " + device.getName() + ": " + device.getAddress());
mDeviceListAdapter = new DeviceListAdapter(context, R.layout.device_adapter_view, mBTDevices);
lvNewDevices.setAdapter(mDeviceListAdapter);
}
}
};
/**
* Broadcast Receiver that detects bond state changes (Pairing status changes)
*/
private final BroadcastReceiver mBroadcastReceiver4 = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if(action.equals(BluetoothDevice.ACTION_BOND_STATE_CHANGED)){
BluetoothDevice mDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
//3 cases:
//case1: bonded already
if (mDevice.getBondState() == BluetoothDevice.BOND_BONDED){
Log.d(TAG, "BroadcastReceiver: BOND_BONDED.");
}
//case2: creating a bone
if (mDevice.getBondState() == BluetoothDevice.BOND_BONDING) {
Log.d(TAG, "BroadcastReceiver: BOND_BONDING.");
}
//case3: breaking a bond
if (mDevice.getBondState() == BluetoothDevice.BOND_NONE) {
Log.d(TAG, "BroadcastReceiver: BOND_NONE.");
}
}
}
};
#Override
protected void onDestroy() {
Log.d(TAG, "onDestroy: called.");
super.onDestroy();
unregisterReceiver(mBroadcastReceiver1);
unregisterReceiver(mBroadcastReceiver2);
unregisterReceiver(mBroadcastReceiver3);
unregisterReceiver(mBroadcastReceiver4);
//mBluetoothAdapter.cancelDiscovery();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnONOFF = (Button) findViewById(R.id.btnONOFF);
btnEnableDisable_Discoverable = (Button) findViewById(R.id.btnDiscoverable_on_off);
lvNewDevices = (ListView) findViewById(R.id.lvNewDevices);
mBTDevices = new ArrayList<>();
//Broadcasts when bond state changes (ie:pairing)
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
registerReceiver(mBroadcastReceiver4, filter);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
lvNewDevices.setOnItemClickListener(MainActivity.this);
btnONOFF.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Log.d(TAG, "onClick: enabling/disabling bluetooth.");
enableDisableBT();
}
});
}
public void enableDisableBT(){
if(mBluetoothAdapter == null){
Log.d(TAG, "enableDisableBT: Does not have BT capabilities.");
}
if(!mBluetoothAdapter.isEnabled()){
Log.d(TAG, "enableDisableBT: enabling BT.");
Intent enableBTIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivity(enableBTIntent);
IntentFilter BTIntent = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mBroadcastReceiver1, BTIntent);
}
if(mBluetoothAdapter.isEnabled()){
Log.d(TAG, "enableDisableBT: disabling BT.");
mBluetoothAdapter.disable();
IntentFilter BTIntent = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mBroadcastReceiver1, BTIntent);
}
}
public void btnEnableDisable_Discoverable(View view) {
Log.d(TAG, "btnEnableDisable_Discoverable: Making device discoverable for 300 seconds.");
Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
startActivity(discoverableIntent);
IntentFilter intentFilter = new IntentFilter(mBluetoothAdapter.ACTION_SCAN_MODE_CHANGED);
registerReceiver(mBroadcastReceiver2,intentFilter);
}
public void btnDiscover(View view) {
Log.d(TAG, "btnDiscover: Looking for unpaired devices.");
if(mBluetoothAdapter.isDiscovering()){
mBluetoothAdapter.cancelDiscovery();
Log.d(TAG, "btnDiscover: Canceling discovery.");
//check BT permissions in manifest
checkBTPermissions();
mBluetoothAdapter.startDiscovery();
IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mBroadcastReceiver3, discoverDevicesIntent);
}
if(!mBluetoothAdapter.isDiscovering()){
//check BT permissions in manifest
checkBTPermissions();
mBluetoothAdapter.startDiscovery();
IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mBroadcastReceiver3, discoverDevicesIntent);
}
}
/**
* This method is required for all devices running API23+
* Android must programmatically check the permissions for bluetooth. Putting the proper permissions
* in the manifest is not enough.
*
* NOTE: This will only execute on versions > LOLLIPOP because it is not needed otherwise.
*/
private void checkBTPermissions() {
if(Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP){
int permissionCheck = this.checkSelfPermission("Manifest.permission.ACCESS_FINE_LOCATION");
permissionCheck += this.checkSelfPermission("Manifest.permission.ACCESS_COARSE_LOCATION");
if (permissionCheck != 0) {
this.requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, 1001); //Any number
}
}else{
Log.d(TAG, "checkBTPermissions: No need to check permissions. SDK version < LOLLIPOP.");
}
}
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
//first cancel discovery because its very memory intensive.
mBluetoothAdapter.cancelDiscovery();
Log.d(TAG, "onItemClick: You Clicked on a device.");
String deviceName = mBTDevices.get(i).getName();
String deviceAddress = mBTDevices.get(i).getAddress();
Log.d(TAG, "onItemClick: deviceName = " + deviceName);
Log.d(TAG, "onItemClick: deviceAddress = " + deviceAddress);
//create the bond.
//NOTE: Requires API 17+? I think this is JellyBean
if(Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN_MR2){
Log.d(TAG, "Trying to pair with " + deviceName);
mBTDevices.get(i).createBond();
}
}
}
/// Here is also my DeviceListAdapter code:
public class DeviceListAdapter extends ArrayAdapter<BluetoothDevice> {
private LayoutInflater mLayoutInflater;
private ArrayList<BluetoothDevice> mDevices;
private int mViewResourceId;
public DeviceListAdapter(Context context, int tvResourceId, ArrayList<BluetoothDevice> devices){
super(context, tvResourceId,devices);
this.mDevices = devices;
mLayoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mViewResourceId = tvResourceId;
}
public View getView(int position, View convertView, ViewGroup parent) {
convertView = mLayoutInflater.inflate(mViewResourceId, null);
BluetoothDevice device = mDevices.get(position);
if (device != null) {
TextView deviceName = (TextView) convertView.findViewById(R.id.tvDeviceName);
TextView deviceAdress = (TextView) convertView.findViewById(R.id.tvDeviceAddress);
if (deviceName != null) {
deviceName.setText(device.getName());
}
if (deviceAdress != null) {
deviceAdress.setText(device.getAddress());
}
}
return convertView;
}
}

Some of the tutorials on Bluetooth are pretty old! I just got Arduino-Android Bluetooth communication working last week so this should work for you! First in your manifest file add these permissions:
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
Then use this in your main.
public class MainActivity extends AppCompatActivity {
private final String DEVICE_ADDRESS="benamekhoda"; //I actually used Device Name instead of address
private final UUID PORT_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); //Serial Port Service UUID
private BluetoothDevice device; //Our Bluetooth Device
private BluetoothSocket socket;
private OutputStream outputStream;
private InputStream inputStream;
Button startButton, sendButton,clearButton,stopButton;
TextView textView;
EditText editText;
boolean deviceConnected=false;
Thread thread;
byte buffer[];
int bufferPosition;
boolean stopThread;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = (EditText) findViewById(R.id.edittext);
textView = (TextView) findViewById(R.id.textview);
startButton = (Button) findViewById(R.id.buttonStart);
startButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(BTinit())
{
if(BTconnect())
{
setUiEnabled(true);
deviceConnected=true;
beginListenForData();
textView.append("\nConnection Opened!\n");
}
else{
Toast.makeText(getApplicationContext(),"BTconnect false",Toast.LENGTH_SHORT).show();
}
}
else{
Toast.makeText(getApplicationContext(),"BTinit false",Toast.LENGTH_SHORT).show();
}
}
});
sendButton = (Button) findViewById(R.id.buttonSend);
sendButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String string = editText.getText().toString();
string.concat("\n");
try {
outputStream.write(string.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
textView.append("\nSent Data:"+string+"\n");
}
});
clearButton = (Button) findViewById(R.id.buttonClear);
clearButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onClickClear(view);
}
});
stopButton = (Button) findViewById(R.id.buttonStop);
stopButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onClickSend(view);
}
});
setUiEnabled(false);
}
public void setUiEnabled(boolean bool)
{
startButton.setEnabled(!bool);
sendButton.setEnabled(bool);
stopButton.setEnabled(bool);
textView.setEnabled(bool);
}
public boolean BTinit()
{
boolean found=false;
BluetoothAdapter bluetoothAdapter=BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
Toast.makeText(getApplicationContext(),"Device doesnt Support Bluetooth",Toast.LENGTH_SHORT).show();
}
if(!bluetoothAdapter.isEnabled())
{
Intent enableAdapter = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableAdapter, 0);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
Set<BluetoothDevice> bondedDevices = bluetoothAdapter.getBondedDevices(); //Something like ArrayList but no duplicate is allowed and data is unordered
if(bondedDevices.isEmpty())
{
Toast.makeText(getApplicationContext(),"Please Pair the Device first",Toast.LENGTH_SHORT).show();
}
else
{
for (BluetoothDevice iterator : bondedDevices)
{
if(iterator.getName().equals(DEVICE_ADDRESS))
{
device=iterator;
Toast.makeText(getApplicationContext(),"found the device",Toast.LENGTH_SHORT).show();
found=true;
break;
}
}
}
return found;
}
public boolean BTconnect()
{
boolean connected=true;
try {
socket = device.createRfcommSocketToServiceRecord(PORT_UUID);
socket.connect();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(),"throw1",Toast.LENGTH_SHORT).show();
connected=false;
}
if(connected)
{
try {
outputStream=socket.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(),"throw2",Toast.LENGTH_SHORT).show();
}
try {
inputStream=socket.getInputStream();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(),"throw3",Toast.LENGTH_SHORT).show();
}
}
return connected;
}
void beginListenForData()
{
final Handler handler = new Handler();
stopThread = false;
buffer = new byte[1024];
Thread thread = new Thread(new Runnable()
{
public void run()
{
while(!Thread.currentThread().isInterrupted() && !stopThread)
{
try
{
int byteCount = inputStream.available();
if(byteCount > 0)
{
byte[] rawBytes = new byte[byteCount];
inputStream.read(rawBytes);
final String string=new String(rawBytes,"UTF-8");
handler.post(new Runnable() {
public void run()
{
textView.append(string);
}
});
}
}
catch (IOException ex)
{
stopThread = true;
Toast.makeText(getApplicationContext(),"throw4",Toast.LENGTH_SHORT).show();
}
}
}
});
thread.start();
}
public void onClickSend(View view) {
String string = editText.getText().toString();
string.concat("\n");
try {
outputStream.write(string.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
textView.append("\nSent Data:"+string+"\n");
}
public void onClickStop(View view) throws IOException {
stopThread = true;
outputStream.close();
inputStream.close();
socket.close();
setUiEnabled(false);
deviceConnected=false;
textView.append("\nConnection Closed!\n");
}
public void onClickClear(View view) {
textView.setText("");
}
}
I got it from this awesome tutorial by Hariharan Mathavan from All About Circuits.

Where is the String Receiving Part in this Code? (Bluetooth chat Application)

I just need to Modify the Bluetooth Chat Application. The String will be Successfully Received in ListView , but i don't have an idea to Where is the String Receiving Part Processing in below Code.
MainActivity.java
public class MainActivity extends AppCompatActivity {
private EditText et_tnum;
private EditText et_pass;
private TextView status;
private Button btnConnect;
private ListView listView;
private Dialog dialog;
private TextInputLayout inputLayout;
private ArrayAdapter<String> chatAdapter;
private ArrayList<String> chatMessages;
private BluetoothAdapter bluetoothAdapter;
public static final int MESSAGE_STATE_CHANGE = 1;
public static final int MESSAGE_READ = 2;
public static final int MESSAGE_WRITE = 3;
public static final int MESSAGE_DEVICE_OBJECT = 4;
public static final int MESSAGE_TOAST = 5;
public static final String DEVICE_OBJECT = "device_name";
private static final int REQUEST_ENABLE_BLUETOOTH = 1;
private ChatController chatController;
private BluetoothDevice connectingDevice;
private ArrayAdapter<String> discoveredDevicesAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewsByIds();
//check device support bluetooth or not
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
Toast.makeText(this, "Bluetooth is not available!", Toast.LENGTH_SHORT).show();
finish();
}
//show bluetooth devices dialog when click connect button
btnConnect.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
showPrinterPickDialog();
}
});
//set chat adapter
chatMessages = new ArrayList<>();
chatAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, chatMessages);
listView.setAdapter(chatAdapter);
}
private Handler handler = new Handler(new Handler.Callback() {
#Override
public boolean handleMessage(Message msg) {
switch (msg.what) {
case MESSAGE_STATE_CHANGE:
switch (msg.arg1) {
case ChatController.STATE_CONNECTED:
setStatus("Connected to: " + connectingDevice.getName());
btnConnect.setEnabled(false);
break;
case ChatController.STATE_CONNECTING:
setStatus("Connecting...");
btnConnect.setEnabled(false);
break;
case ChatController.STATE_LISTEN:
case ChatController.STATE_NONE:
setStatus("Not connected");
break;
}
break;
case MESSAGE_WRITE:
byte[] writeBuf = (byte[]) msg.obj;
String writeMessage = new String(writeBuf);
chatMessages.add("Me: " + writeMessage);
chatAdapter.notifyDataSetChanged();
break;
case MESSAGE_READ:
byte[] readBuf = (byte[]) msg.obj;
String readMessage = new String(readBuf, 0, msg.arg1);
chatMessages.add(connectingDevice.getName() + ": " + readMessage);
chatAdapter.notifyDataSetChanged();
break;
case MESSAGE_DEVICE_OBJECT:
connectingDevice = msg.getData().getParcelable(DEVICE_OBJECT);
Toast.makeText(getApplicationContext(), "Connected to " + connectingDevice.getName(),
Toast.LENGTH_SHORT).show();
break;
case MESSAGE_TOAST:
Toast.makeText(getApplicationContext(), msg.getData().getString("toast"),
Toast.LENGTH_SHORT).show();
break;
}
return false;
}
});
private void showPrinterPickDialog() {
dialog = new Dialog(this);
dialog.setContentView(R.layout.layout_bluetooth);
dialog.setTitle("Bluetooth Devices");
if (bluetoothAdapter.isDiscovering()) {
bluetoothAdapter.cancelDiscovery();
}
bluetoothAdapter.startDiscovery();
//Initializing bluetooth adapters
ArrayAdapter<String> pairedDevicesAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
discoveredDevicesAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
//locate listviews and attatch the adapters
ListView listView = (ListView) dialog.findViewById(R.id.pairedDeviceList);
ListView listView2 = (ListView) dialog.findViewById(R.id.discoveredDeviceList);
listView.setAdapter(pairedDevicesAdapter);
listView2.setAdapter(discoveredDevicesAdapter);
// Register for broadcasts when a device is discovered
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(discoveryFinishReceiver, filter);
// Register for broadcasts when discovery has finished
filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
registerReceiver(discoveryFinishReceiver, filter);
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
// If there are paired devices, add each one to the ArrayAdapter
if (pairedDevices.size() > 0) {
for (BluetoothDevice device : pairedDevices) {
pairedDevicesAdapter.add(device.getName() + "\n" + device.getAddress());
}
} else {
pairedDevicesAdapter.add(getString(R.string.none_paired));
}
//Handling listview item click event
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
bluetoothAdapter.cancelDiscovery();
String info = ((TextView) view).getText().toString();
String address = info.substring(info.length() - 17);
connectToDevice(address);
dialog.dismiss();
}
});
listView2.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
bluetoothAdapter.cancelDiscovery();
String info = ((TextView) view).getText().toString();
String address = info.substring(info.length() - 17);
connectToDevice(address);
dialog.dismiss();
}
});
dialog.findViewById(R.id.cancelButton).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
dialog.dismiss();
}
});
dialog.setCancelable(false);
dialog.show();
}
private void setStatus(String s) {
status.setText(s);
}
private void connectToDevice(String deviceAddress) {
bluetoothAdapter.cancelDiscovery();
BluetoothDevice device = bluetoothAdapter.getRemoteDevice(deviceAddress);
chatController.connect(device);
}
private void findViewsByIds() {
status = (TextView) findViewById(R.id.status);
btnConnect = (Button) findViewById(R.id.btn_connect);
listView = (ListView) findViewById(R.id.list);
et_tnum = (EditText) findViewById(R.id.et_tnum);
et_pass = (EditText) findViewById(R.id.et_pass);
View btnSend = (Button) findViewById(R.id.btn_send);
}
btnSend.setOnClickListener(new View.OnClickListener()
{ #Override
public void onClick(View view)
{ String number =et_tnum.getText().toString();
String password=et_pass.getText().toString();
if (et_pass.getText().toString().equals(""))
{ Toast.makeText(MainActivity.this, "Please input some texts", Toast.LENGTH_SHORT).show(); }
else {
String numberpass= "Account Number:"+number+"\nPassword:"+password;
sendMessage(numberpass);
et_pass.setText("");
}
}
});
public void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case REQUEST_ENABLE_BLUETOOTH:
if (resultCode == Activity.RESULT_OK) {
chatController = new ChatController(this, handler);
} else {
Toast.makeText(this, "Bluetooth still disabled, turn off application!", Toast.LENGTH_SHORT).show();
finish();
}
}
}
private void sendMessage(String message) {
if (chatController.getState() != ChatController.STATE_CONNECTED) {
Toast.makeText(this, "Connection was lost!", Toast.LENGTH_SHORT).show();
return;
}
if (message.length() > 0) {
byte[] send = message.getBytes();
chatController.write(send);
}
}
#Override
public void onStart() {
super.onStart();
if (!bluetoothAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BLUETOOTH);
} else {
chatController = new ChatController(this, handler);
}
}
#Override
public void onResume() {
super.onResume();
if (chatController != null) {
if (chatController.getState() == ChatController.STATE_NONE) {
chatController.start();
}
}
}
#Override
public void onDestroy() {
super.onDestroy();
if (chatController != null)
chatController.stop();
}
private final BroadcastReceiver discoveryFinishReceiver = 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);
if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
String recieverAddress = device.getName();
String recieverPassword = device.getAddress();
et_tnum.setText(recieverAddress);
et_pass.setText(recieverPassword);
}
} else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
if (discoveredDevicesAdapter.getCount() == 0) {
discoveredDevicesAdapter.add(getString(R.string.none_found));
}
}
}
};
}
activity_main.xml
<LinearLayout
android:layout_width="348dp"
android:layout_height="80dp"
android:orientation="vertical">
<TextView
android:id="#+id/status"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Not Connected" />
<Button
android:id="#+id/btn_connect"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="Connect" />
</LinearLayout>
<ListView
android:id="#+id/list"
android:layout_width="332dp"
android:layout_height="164dp" />
<EditText
android:id="#+id/et_tnum"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Account Number"
android:inputType="textEmailAddress|textPersonName" />
<EditText
android:id="#+id/et_pass"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Password"
android:inputType="textPassword" />
<Button
android:id="#+id/btn_send"
android:layout_width="213dp"
android:layout_height="wrap_content"
android:text="verify" />

it's at
case MESSAGE_READ:
//read recieved data
byte[] readBuf = (byte[]) msg.obj;
//convert recieved data to String
//readMessage is your String where the recieved message is saved
String readMessage = new String(readBuf, 0, msg.arg1);
chatMessages.add(connectingDevice.getName() + ": " + readMessage);
chatAdapter.notifyDataSetChanged();
break;

Print using Bluetooth printer in android not working

I am working on application which allows user to create PDF and also allows to print it using Bluetooth printer.
I created PDF but whenever i'm going to integrate print functionality using Bluetooth printer, it occurs error over there.
I couldn't get list of Bluetooth device.
If you have any sample code for it then please provide it to me.It is too important to me.
Thank You....
This is my code
PrintActivity.java
public class PrintActivity extends Activity implements Runnable {
int idd;
protected static final String TAG = "TAG";
private static final int REQUEST_CONNECT_DEVICE = 1;
private static final int REQUEST_ENABLE_BT = 2;
Button btnPrinr;
BluetoothAdapter mBluetoothAdapter;
private UUID applicationUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
private ProgressDialog mBluetoothConnectProgressDialog;
private BluetoothSocket mBluetoothSocket;
BluetoothDevice mBluetoothDevice;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_print);
idd = getIntent().getIntExtra("ID", 0);
Log.e("ID", "" + idd);
btnPrinr = (Button) findViewById(R.id.btnPrinr);
btnPrinr.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
Toast.makeText(PrintActivity.this, "Message1", Toast.LENGTH_SHORT).show();
} else {
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
} else {
ListPairedDevices();
Intent connectIntent = new Intent(PrintActivity.this, DeviceListActivity.class);
startActivityForResult(connectIntent, REQUEST_CONNECT_DEVICE);
}
}
}
});
}
public void onActivityResult(int mRequestCode, int mResultCode, Intent mDataIntent) {
super.onActivityResult(mRequestCode, mResultCode, mDataIntent);
switch (mRequestCode) {
case REQUEST_CONNECT_DEVICE:
if (mResultCode == Activity.RESULT_OK) {
Bundle mExtra = mDataIntent.getExtras();
String mDeviceAddress = mExtra.getString("DeviceAddress");
Log.v(TAG, "Coming incoming address " + mDeviceAddress);
mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(mDeviceAddress);
mBluetoothConnectProgressDialog = ProgressDialog.show(this, "Connecting...", mBluetoothDevice.getName() + " : " + mBluetoothDevice.getAddress(), true, false);
Thread mBlutoothConnectThread = new Thread(this);
mBlutoothConnectThread.start();
//pairToDevice(mBluetoothDevice); This method is replaced by progress dialog with thread
}
break;
case REQUEST_ENABLE_BT:
if (mResultCode == Activity.RESULT_OK) {
ListPairedDevices();
Intent connectIntent = new Intent(PrintActivity.this, DeviceListActivity.class);
startActivityForResult(connectIntent, REQUEST_CONNECT_DEVICE);
} else {
Toast.makeText(PrintActivity.this, "Message", Toast.LENGTH_SHORT).show();
}
break;
}
}
private void ListPairedDevices() {
Set<BluetoothDevice> mPairedDevices = mBluetoothAdapter.getBondedDevices();
if (mPairedDevices.size() > 0) {
for (BluetoothDevice mDevice : mPairedDevices) {
Log.v(TAG, "PairedDevices: " + mDevice.getName() + " " + mDevice.getAddress());
}
}
}
public void run() {
try {
mBluetoothSocket = mBluetoothDevice.createRfcommSocketToServiceRecord(applicationUUID);
mBluetoothAdapter.cancelDiscovery();
mBluetoothSocket.connect();
mHandler.sendEmptyMessage(0);
} catch (IOException eConnectException) {
Log.d(TAG, "CouldNotConnectToSocket", eConnectException);
closeSocket(mBluetoothSocket);
return;
}
}
private void closeSocket(BluetoothSocket nOpenSocket) {
try {
nOpenSocket.close();
Log.d(TAG, "SocketClosed");
} catch (IOException ex) {
Log.d(TAG, "CouldNotCloseSocket");
}
}
private Handler mHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
mBluetoothConnectProgressDialog.dismiss();
Toast.makeText(PrintActivity.this, "DeviceConnected", Toast.LENGTH_SHORT).show();
}
};
}
DeviceListActivity.java
public class DeviceListActivity extends Activity {
protected static final String TAG = "TAG";
private BluetoothAdapter mBluetoothAdapter;
private ArrayAdapter<String> mPairedDevicesArrayAdapter;
TextView txtName;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
setContentView(R.layout.activity_device_list);
setResult(Activity.RESULT_CANCELED);
mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.simple_list_raw,R.id.txtName);
ListView mPairedListView = (ListView) findViewById(R.id.paired_devices);
mPairedListView.setAdapter(mPairedDevicesArrayAdapter);
mPairedListView.setOnItemClickListener(mDeviceClickListener);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set<BluetoothDevice> mPairedDevices = mBluetoothAdapter.getBondedDevices();
if (mPairedDevices.size() > 0) {
findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
for (BluetoothDevice mDevice : mPairedDevices) {
mPairedDevicesArrayAdapter.add(mDevice.getName() + "\n" + mDevice.getAddress());
}
} else {
String mNoDevices = getResources().getText(R.string.none_paired).toString();
mPairedDevicesArrayAdapter.add(mNoDevices);
}
}
#Override
protected void onDestroy() {
super.onDestroy();
if (mBluetoothAdapter != null) {
mBluetoothAdapter.cancelDiscovery();
}
}
private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
public void onItemClick(AdapterView<?> mAdapterView, View mView, int mPosition, long mLong) {
mBluetoothAdapter.cancelDiscovery();
String mDeviceInfo = ((TextView) mView).getText().toString();
String mDeviceAddress = mDeviceInfo.substring(mDeviceInfo.length() - 15);
Log.v(TAG, "Device_Address " + mDeviceAddress);
Bundle mBundle = new Bundle();
mBundle.putString("DeviceAddress", mDeviceAddress);
Intent mBackIntent = new Intent();
mBackIntent.putExtras(mBundle);
setResult(Activity.RESULT_OK, mBackIntent);
finish();
}
};
}

In the code I'm using after this line, there is another line that yours is missing
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
mBluetoothAdapter.startDiscovery();
I hope this helps, I'm only starting with android studio but since no one has answered this question I hope mine helps...

Message and File Transfer using Bluetooth in android

I am developing an application in which first we have to search and connect available paired Bluetooth devices. I have done till connection. But after that I have put one screen which asks to choose between Text and file transfer. When I select text then one more screen will open in which there are edittext and button. Whatever user types in edittext and clicks on button that should be transferd to connected BT device like BT chat application. I have gone through BT chat app but it is complex to understand. I want a seperate function which does transferring task. Below is my connection code.
Main.java
public class Main extends Activity implements Runnable
{
protected static final String TAG = "TAG";
private static final int REQUEST_CONNECT_DEVICE = 1;
private static final int REQUEST_ENABLE_BT = 2;
Button mScan;
BluetoothAdapter mBluetoothAdapter;
private UUID applicationUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
private ProgressDialog mBluetoothConnectProgressDialog;
private BluetoothSocket mBluetoothSocket;
BluetoothDevice mBluetoothDevice;
#Override
public void onCreate(Bundle mSavedInstanceState)
{
super.onCreate(mSavedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
mScan = (Button) findViewById(R.id.Scan);
mScan.setOnClickListener(new View.OnClickListener()
{
public void onClick(View mView)
{
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null)
{
Toast.makeText(Main.this, "Message1", 2000).show();
}
else
{
if (!mBluetoothAdapter.isEnabled())
{
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
else
{
ListPairedDevices();
Intent connectIntent = new Intent(Main.this, DeviceListActivity.class);
startActivityForResult(connectIntent, REQUEST_CONNECT_DEVICE);
}
}
}
});
}
public void onActivityResult(int mRequestCode, int mResultCode, Intent mDataIntent)
{
super.onActivityResult(mRequestCode, mResultCode, mDataIntent);
switch (mRequestCode)
{
case REQUEST_CONNECT_DEVICE:
if (mResultCode == Activity.RESULT_OK)
{
Bundle mExtra = mDataIntent.getExtras();
String mDeviceAddress = mExtra.getString("DeviceAddress");
Log.v(TAG, "Coming incoming address " + mDeviceAddress);
mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(mDeviceAddress);
mBluetoothConnectProgressDialog = ProgressDialog.show(this, "Connecting...", mBluetoothDevice.getName() + " : " + mBluetoothDevice.getAddress(), true, false);
Thread mBlutoothConnectThread = new Thread(this);
mBlutoothConnectThread.start();
//pairToDevice(mBluetoothDevice); This method is replaced by progress dialog with thread
}
break;
case REQUEST_ENABLE_BT:
if (mResultCode == Activity.RESULT_OK)
{
ListPairedDevices();
Intent connectIntent = new Intent(Main.this, DeviceListActivity.class);
startActivityForResult(connectIntent, REQUEST_CONNECT_DEVICE);
}
else
{
Toast.makeText(Main.this, "Message", 2000).show();
}
break;
}
}
private void ListPairedDevices()
{
Set<BluetoothDevice> mPairedDevices = mBluetoothAdapter.getBondedDevices();
if (mPairedDevices.size() > 0)
{
for (BluetoothDevice mDevice : mPairedDevices)
{
Log.v(TAG, "PairedDevices: " + mDevice.getName() + " " + mDevice.getAddress());
}
}
}
public void run()
{
try
{
mBluetoothSocket = mBluetoothDevice.createRfcommSocketToServiceRecord(applicationUUID);
mBluetoothAdapter.cancelDiscovery();
mBluetoothSocket.connect();
mHandler.sendEmptyMessage(0);
}
catch (IOException eConnectException)
{
Log.d(TAG, "CouldNotConnectToSocket", eConnectException);
closeSocket(mBluetoothSocket);
return;
}
}
private void closeSocket(BluetoothSocket nOpenSocket)
{
try
{
nOpenSocket.close();
Log.d(TAG, "SocketClosed");
}
catch (IOException ex)
{
Log.d(TAG, "CouldNotCloseSocket");
}
}
private Handler mHandler = new Handler()
{
#Override
public void handleMessage(Message msg)
{
mBluetoothConnectProgressDialog.dismiss();
Toast.makeText(Main.this, "Device Connected", 5000).show();
Intent in = new Intent(getBaseContext(), Option.class);
startActivity(in);
}
};
}
DeviceListActivity.java
public class DeviceListActivity extends Activity
{
protected static final String TAG = "TAG";
private BluetoothAdapter mBluetoothAdapter;
private ArrayAdapter<String> mPairedDevicesArrayAdapter;
#Override
protected void onCreate(Bundle mSavedInstanceState)
{
super.onCreate(mSavedInstanceState);
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
setContentView(R.layout.device_list);
setResult(Activity.RESULT_CANCELED);
mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
ListView mPairedListView = (ListView) findViewById(R.id.paired_devices);
mPairedListView.setAdapter(mPairedDevicesArrayAdapter);
mPairedListView.setOnItemClickListener(mDeviceClickListener);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set<BluetoothDevice> mPairedDevices = mBluetoothAdapter.getBondedDevices();
if (mPairedDevices.size() > 0)
{
findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
for (BluetoothDevice mDevice : mPairedDevices)
{
mPairedDevicesArrayAdapter.add(mDevice.getName() + "\n" + mDevice.getAddress());
}
}
else
{
String mNoDevices = getResources().getText(R.string.none_paired).toString();
mPairedDevicesArrayAdapter.add(mNoDevices);
}
}
#Override
protected void onDestroy()
{
super.onDestroy();
if (mBluetoothAdapter != null)
{
mBluetoothAdapter.cancelDiscovery();
}
}
private OnItemClickListener mDeviceClickListener = new OnItemClickListener()
{
public void onItemClick(AdapterView<?> mAdapterView, View mView, int mPosition, long mLong)
{
mBluetoothAdapter.cancelDiscovery();
String mDeviceInfo = ((TextView) mView).getText().toString();
String mDeviceAddress = mDeviceInfo.substring(mDeviceInfo.length() - 17);
Log.v(TAG, "Device_Address " + mDeviceAddress);
Bundle mBundle = new Bundle();
mBundle.putString("DeviceAddress", mDeviceAddress);
Intent mBackIntent = new Intent();
mBackIntent.putExtras(mBundle);
setResult(Activity.RESULT_OK, mBackIntent);
finish();
}
};
}
option.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/file" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/txt" />
</LinearLayout>
message.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<EditText
android:id="#+id/editText1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="#string/hint">
<requestFocus />
</EditText>
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/send" />
</LinearLayout>

Call to following method:
private void sendDataToPairedDevice(String message ,BluetoothDevice device){
byte[] toSend = message.getBytes();
try {
BluetoothSocket socket = device.createInsecureRfcommSocketToServiceRecord(applicationUUID);
OutputStream mmOutStream = socket.getOutputStream();
mmOutStream.write(toSend);
// Your Data is sent to BT connected paired device ENJOY.
} catch (IOException e) {
Log.e(TAG, "Exception during write", e);
}
}
Now Put following in Your Oncreate of the Activity with EditText.
EditText editText1 = (EditText) findViewById(R.id.editText1);
And Call above method like
sendDataToPairedDevice(editText1.getText() ,mBluetoothDevice);
in The Onclick of your desired button.
thats it.
just upvote if you use it, thanks, enjoy buddy.

public void onClick(View v) {
// TODO Auto-generated method stub
mBluetoothAdapter1 = BluetoothAdapter.getDefaultAdapter();
byte[] toSend=message1.getBytes();
try
{
final UUID applicationUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
BluetoothDevice device=mBluetoothAdapter1.getRemoteDevice(MacAddress);
BluetoothSocket socket=device.createInsecureRfcommSocketToServiceRecord(applicationUUID);
OutputStream mmout=socket.getOutputStream();
mmout.write(toSend);
mmout.flush();
mmout.close();
socket.close();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});

Finally got the Answer...
BluetoothAdapter mBluetoothAdapter = null;
BluetoothDevice m1BluetoothDevice;
public static BluetoothSocket socket;//Get this value from Main Activity
Button btn;
EditText et;
public static String MacAddressesss;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.message);
btn=(Button)findViewById(R.id.btn);
et=(EditText)findViewById(R.id.et);
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
try
{
String msg=et.getText().toString();
byte tosend= msg.getBytes();
OutputStream out= socket.getOutputStream();
out.write(tosend);
}
catch(IOException e)
{
e.printStackTrace();
}
}
});
}
}