Bluetooth Communication

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.java2s.myapplication3.app" >
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
    <uses-permission android:name="android.permission.BLUETOOTH"></uses-permission>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"></uses-permission>
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="java2s.com"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.java2s.myapplication3.app.MainActivity"
            android:label="java2s.com"
            >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
  <TextView
    android:id="@+id/label"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="Enter Your Email:"
  />
  <EditText
    android:id="@+id/emailField"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/label"
    android:singleLine="true"
    android:inputType="textEmailAddress"
  />
  <Button
    android:id="@+id/scanButton"
    android:layout_width="fill_parent" 
     android:layout_height="wrap_content"
     android:layout_alignParentBottom="true"
     android:text="Connect and Share"
  />
  <Button
    android:id="@+id/listenButton"
    android:layout_width="fill_parent" 
     android:layout_height="wrap_content"
     android:layout_above="@id/scanButton"
     android:text="Listen for Sharers"
  />
</RelativeLayout>

/**/*  www . jav a  2 s .  c  om*/
 * Created on May 19, 2010 by Dave Smith
 * Wireless Designs, LLC
 * 
 */

package com.java2s.myapplication3.app;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
    private static final UUID MY_UUID = UUID.fromString("311cb9fa-9066-5f58-945e-ef56d1ae16ec");
    private static final String SEARCH_NAME = "bluetooth.recipe";

    BluetoothAdapter mBtAdapter;
    BluetoothSocket mBtSocket;
    Button listenButton, scanButton;
    EditText emailField;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setTitle("Activity");
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        setContentView(R.layout.activity_main);

        mBtAdapter = BluetoothAdapter.getDefaultAdapter();
        if(mBtAdapter == null) {
            Toast.makeText(this, "Bluetooth is not supported.", Toast.LENGTH_SHORT).show();
            finish();
            return;
        }
        if (!mBtAdapter.isEnabled()) {
            Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableIntent, REQUEST_ENABLE);
        }

        emailField = (EditText)findViewById(R.id.emailField);
        listenButton = (Button)findViewById(R.id.listenButton);
        listenButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Make sure the device is discoverable first
                if (mBtAdapter.getScanMode() != BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
                    Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
                    discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
                    startActivityForResult(discoverableIntent, REQUEST_DISCOVERABLE);
                    return;
                }
                startListening();
            }
        });
        scanButton = (Button)findViewById(R.id.scanButton);
        scanButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mBtAdapter.startDiscovery();
                setProgressBarIndeterminateVisibility(true);
            }
        });
    }

    @Override
    public void onResume() {
        super.onResume();
        //Register the activity for broadcast intents
        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        registerReceiver(mReceiver, filter);
        filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        registerReceiver(mReceiver, filter);
    }

    @Override
    public void onPause() {
        super.onPause();
        unregisterReceiver(mReceiver);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        try {
            if(mBtSocket != null) {
                mBtSocket.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static final int REQUEST_ENABLE = 1;
    private static final int REQUEST_DISCOVERABLE = 2;

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch(requestCode) {
            case REQUEST_ENABLE:
                if(resultCode != Activity.RESULT_OK) {
                    Toast.makeText(this, "Bluetooth Not Enabled.", Toast.LENGTH_SHORT).show();
                    finish();
                }
                break;
            case REQUEST_DISCOVERABLE:
                if(resultCode == Activity.RESULT_CANCELED) {
                    Toast.makeText(this, "Cannot listen unless we are discoverable.", Toast.LENGTH_SHORT).show();
                } else {
                    startListening();
                }
                break;
            default:
                break;
        }
    }

    private void startListening() {
        AcceptTask task = new AcceptTask();
        task.execute(MY_UUID);
        setProgressBarIndeterminateVisibility(true);
    }

    //AsyncTask to accept incoming connections
    private class AcceptTask extends AsyncTask<UUID,Void,BluetoothSocket> {

        @Override
        protected BluetoothSocket doInBackground(UUID... params) {
            String name = mBtAdapter.getName();
            try {
                //While listening, set the discovery name to a specific value
                mBtAdapter.setName(SEARCH_NAME);
                BluetoothServerSocket socket = mBtAdapter.listenUsingRfcommWithServiceRecord("BluetoothRecipe", params[0]);
                BluetoothSocket connected = socket.accept();
                //Reset the BT adapter name
                mBtAdapter.setName(name);
                return connected;
            } catch (IOException e) {
                e.printStackTrace();
                mBtAdapter.setName(name);
                return null;
            }
        }

        @Override
        protected void onPostExecute(BluetoothSocket socket) {
            if(socket == null) {
                return;
            }
            mBtSocket = socket;
            ConnectedTask task = new ConnectedTask();
            task.execute(mBtSocket);
        }

    }

    //AsyncTask to receive a single line of data and post
    private class ConnectedTask extends AsyncTask<BluetoothSocket,Void,String> {

        @Override
        protected String doInBackground(BluetoothSocket... params) {
            InputStream in = null;
            OutputStream out = null;
            try {
                //Send your data
                out = params[0].getOutputStream();
                out.write(emailField.getText().toString().getBytes());
                //Receive the other's data
                in = params[0].getInputStream();
                byte[] buffer = new byte[1024];
                in.read(buffer);
                //Create a clean string from results
                String result = new String(buffer);
                //Close the connection
                mBtSocket.close();
                return result.trim();
            } catch (Exception exc) {
                return null;
            }
        }

        @Override
        protected void onPostExecute(String result) {

            Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT).show();
            setProgressBarIndeterminateVisibility(false);
        }

    }

    // The BroadcastReceiver that listens for discovered devices
    private BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        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);
                if(TextUtils.equals(device.getName(), SEARCH_NAME)) {
                    //Matching device found, connect
                    mBtAdapter.cancelDiscovery();
                    try {
                        mBtSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
                        mBtSocket.connect();
                        ConnectedTask task = new ConnectedTask();
                        task.execute(mBtSocket);
                    } catch (IOException e) {
                        e.printStackTrace();
                        Toast.makeText(MainActivity.this, "Error connecting to remote", Toast.LENGTH_SHORT).show();
                    }
                }
                //When discovery is complete
            } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
                setProgressBarIndeterminateVisibility(false);
            }

        }
    };
}