Send and receive data via bluetooth

Question

you can say that I am new to Android development, I need help to synchronize some data on two devices with my application, I did everything necessary, like finding available devices and pairing and decoupling ... all I now need to establish a connection between two devices and send and receive data to explain more, I need to select a device from my list and connect to it, after which I can say that I have a text box and a text box and a button, when I press the button, I need to avit text into the text field of the first device in a textual representation of the device and vice versa. here is all my code:

import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.app.Activity; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothSocket; import android.content.BroadcastReceiver; import android.content.Context; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.Set; import java.util.UUID; import android.content.Intent; import android.content.IntentFilter; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity { private static final int REQUEST_ENABLE_BT = 1; private Button onBtn; private Button offBtn; private Button listBtn; private Button findBtn; private TextView text; private BluetoothAdapter myBluetoothAdapter; private Set<BluetoothDevice> pairedDevices; private ArrayList<BluetoothDevice> devices; private ListView myListView; private ArrayAdapter<String> BTArrayAdapter; private String tag = "debugging"; protected static final UUID MY_UUID = UUID .fromString("00001101-0000-1000-8000-00805F9B34FB"); protected static final int SUCCESS_CONNECT = 0; protected static final int MESSAGE_READ = 1; private Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { Log.i(tag, "in handler"); super.handleMessage(msg); switch (msg.what) { case SUCCESS_CONNECT: // DO something ConnectedThread connectedThread = new ConnectedThread( (BluetoothSocket) msg.obj); Toast.makeText(getApplicationContext(), "CONNECT", 0).show(); String s = "successfully connected"; connectedThread.write(s.getBytes()); Log.i(tag, "connected"); break; case MESSAGE_READ: byte[] readBuf = (byte[]) msg.obj; String string = new String(readBuf); Toast.makeText(getApplicationContext(), string, 0).show(); break; } } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // take an instance of BluetoothAdapter - Bluetooth radio myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); if (myBluetoothAdapter == null) { onBtn.setEnabled(false); offBtn.setEnabled(false); listBtn.setEnabled(false); findBtn.setEnabled(false); text.setText("Status: not supported"); Toast.makeText(getApplicationContext(), "Your device does not support Bluetooth", Toast.LENGTH_LONG) .show(); } else { myListView = (ListView) findViewById(R.id.listView1); BTArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1); devices = new ArrayList<BluetoothDevice>(); myListView.setAdapter(BTArrayAdapter); text = (TextView) findViewById(R.id.text); onBtn = (Button) findViewById(R.id.turnOn); onBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { on(v); } }); offBtn = (Button) findViewById(R.id.turnOff); offBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { off(v); } }); listBtn = (Button) findViewById(R.id.paired); listBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { list(v); } }); findBtn = (Button) findViewById(R.id.search); findBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { find(v); } }); // create the arrayAdapter that contains the BTDevices, and set it // to the ListView myListView.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { if (myBluetoothAdapter.isDiscovering()) { myBluetoothAdapter.cancelDiscovery(); } BluetoothDevice selectedDevice = devices.get(position); if (pairedDevices.contains(selectedDevice)) { if (unpairDevice(selectedDevice)) Toast.makeText(getApplicationContext(), "Device unpaired", Toast.LENGTH_LONG) .show(); else Toast.makeText(getApplicationContext(), "Problem while unpairing device", Toast.LENGTH_LONG).show(); } else { if (pairDevice(selectedDevice)) { Toast.makeText(getApplicationContext(), "Device paired", Toast.LENGTH_LONG).show(); ConnectThread connect = new ConnectThread( selectedDevice); connect.start(); } else Toast.makeText(getApplicationContext(), "Problem while pairing device", Toast.LENGTH_LONG).show(); } } }); } } // For Pairing private boolean pairDevice(BluetoothDevice device) { try { Log.d("pairDevice()", "Start Pairing..."); Method m = device.getClass() .getMethod("createBond", (Class[]) null); m.invoke(device, (Object[]) null); return true; } catch (Exception e) { return false; } } // For UnPairing private boolean unpairDevice(BluetoothDevice device) { try { Log.d("unpairDevice()", "Start Un-Pairing..."); Method m = device.getClass() .getMethod("removeBond", (Class[]) null); m.invoke(device, (Object[]) null); return true; } catch (Exception e) { return false; } } public void on(View view) { if (!myBluetoothAdapter.isEnabled()) { Intent turnOnIntent = new Intent( BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(turnOnIntent, REQUEST_ENABLE_BT); Toast.makeText(getApplicationContext(), "Bluetooth turned on", Toast.LENGTH_LONG).show(); } else { Toast.makeText(getApplicationContext(), "Bluetooth is already on", Toast.LENGTH_LONG).show(); } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == REQUEST_ENABLE_BT) { if (myBluetoothAdapter.isEnabled()) { text.setText("Status: Enabled"); } else { text.setText("Status: Disabled"); } } } public void list(View view) { BTArrayAdapter.clear(); // get paired devices // pairedDevices.clear(); pairedDevices = myBluetoothAdapter.getBondedDevices(); // put it one to the adapter for (BluetoothDevice device : pairedDevices) BTArrayAdapter.add(device.getName() + "\n" + device.getAddress()); Toast.makeText(getApplicationContext(), "Show Paired Devices", Toast.LENGTH_SHORT).show(); } final BroadcastReceiver bReceiver = new BroadcastReceiver() { public void onReceive(Context context, Intent intent) { String action = intent.getAction(); // When discovery finds a device if (BluetoothDevice.ACTION_FOUND.equals(action)) { // Get the BluetoothDevice object from the Intent BluetoothDevice device = intent .getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); // add the name and the MAC address of the object to the // arrayAdapter devices.add(device); BTArrayAdapter.add(device.getName() + "\n" + device.getAddress()); BTArrayAdapter.notifyDataSetChanged(); } } }; public void find(View view) { if (myBluetoothAdapter.isDiscovering()) { // the button is pressed when it discovers, so cancel the discovery Toast.makeText(getApplicationContext(), "Discovery cancelled", Toast.LENGTH_SHORT).show(); myBluetoothAdapter.cancelDiscovery(); } else { Toast.makeText(getApplicationContext(), "Discovering new devices", Toast.LENGTH_SHORT).show(); BTArrayAdapter.clear(); myBluetoothAdapter.startDiscovery(); registerReceiver(bReceiver, new IntentFilter( BluetoothDevice.ACTION_FOUND)); } } public void off(View view) { myBluetoothAdapter.disable(); text.setText("Status: Disconnected"); Toast.makeText(getApplicationContext(), "Bluetooth turned off", Toast.LENGTH_LONG).show(); } @Override protected void onDestroy() { super.onDestroy(); unregisterReceiver(bReceiver); } 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; Log.i(tag, "construct"); // Get a BluetoothSocket to connect with the given BluetoothDevice try { // MY_UUID is the app UUID string, also used by the server // code tmp = device.createRfcommSocketToServiceRecord(MY_UUID); } catch (IOException e) { Log.i(tag, "get socket failed"); } mmSocket = tmp; } public void run() { // Cancel discovery because it will slow down the connection myBluetoothAdapter.cancelDiscovery(); Log.i(tag, "connect - run"); try { // Connect the device through the socket. This will block // until it succeeds or throws an exception mmSocket.connect(); Log.i(tag, "connect - succeeded"); } catch (IOException connectException) { Log.i(tag, "connect failed"); // 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) { } } } 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; // 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 buffer = new byte[1024]; 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) { } } } }