Develop Reference

R cannot be resolved to a variable --

package br.com.buceta;
import java.io.IOException;
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.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final String TAG = "bluetooth1";
Button btnOn, btnOff;
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private OutputStream outStream = null;
// 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 = "00:15:FF:F2:19:5F";
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); (error)
btnOn = (Button) findViewById(R.id.btnOn); (error)
btnOff = (Button) findViewById(R.id.btnOff); (error)
btAdapter = BluetoothAdapter.getDefaultAdapter();
checkBTState();
btnOn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("1");
Toast.makeText(getBaseContext(), "Turn on LED", Toast.LENGTH_SHORT).show();
}
});
btnOff.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("0");
Toast.makeText(getBaseContext(), "Turn off LED", 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 e1) {
errorExit("Fatal Error", "In onResume() and socket create failed: " + e1.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...");
try {
outStream = btSocket.getOutputStream();
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and output stream creation failed:" + e.getMessage() + ".");
}
}
#Override
public void onPause() {
super.onPause();
Log.d(TAG, "...In onPause()...");
if (outStream != null) {
try {
outStream.flush();
} catch (IOException e) {
errorExit("Fatal Error", "In onPause() and failed to flush output stream: " + e.getMessage() + ".");
}
}
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 void sendData(String message) {
byte[] msgBuffer = message.getBytes();
Log.d(TAG, "...Send data: " + message + "...");
try {
outStream.write(msgBuffer);
} catch (IOException e) {
String msg = "In onResume() and an exception occurred during write: " + e.getMessage();
if (address.equals("00:00:00:00:00:00"))
msg = msg + ".\n\nUpdate your server address from 00:00:00:00:00:00 to the correct address on line 35 in the java code";
msg = msg + ".\n\nCheck that the SPP UUID: " + MY_UUID.toString() + " exists on server.\n\n";
errorExit("Fatal Error", msg);
}
}
}
There is no error in R.layout.activity_main, but the code can't recognize the buttons i have declared in activity_main.xml.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="#+id/btnOff"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="#string/btn_OFF" />
<Button
android:id="#+id/btnOn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/btnOff"
android:layout_centerHorizontal="true"
android:text="#string/btn_ON" />
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:alpha="0.5"
android:src="#drawable/cxemnet_logo" />
</RelativeLayout>
Ps.: I solved the 'R cannot be resolved as a type' error by Cleaning > Building project and then this error appeared.

You have to declare your buttons. Either you declare them in your method
...
setContentView(R.layout.activity_main);
Button btnOn = findViewById(R.id.btnOn);
Button btnOff = findViewById(R.id.btnOff);
...
or as a local field
public class Classname {
private Button btnOn;
private Button btnOff;
...
}

Delete gen folder from project and then clean up the whole project also remove your import statement used for r.class used in activity class.

Check your manifest file. You probably forgot to declare something. Usually an Activity.

Eclipse added the "R" import automatically. Unless you are trying to reference resources from another package, it is unnecessary and can be deleted.
For example, if you have a package com.package2 but your manifest has a package name of com.package1 then any class in com.package2 will need:
import com.package1.R;
In your case, it appears to be added automatically. Delete it (don't use "organize imports") and "clean"

Android won't generate R file properly if there is any error in one of the XML files. Maybe the error is in one of them (i.e. the layout file): have you closed all tags? Is there any unsupported attribute?
Try also to organize imports (in windows the shortcut is CTRL+MAIUSC+O [it's a vocal, not zero], in Mac is CMD+MAIUSC+O)

Google Glass GDK: How to Communicate with Android Device

I'm looking for a way to send data between my Android Device and Google Glass that doesn't rely on Cloud API's. Is this supported? I see the Bluetooth connections in the My Glass app, which makes me think it can be done. Is there an example source code that shows how this is done? Or do I have to decompile the MyGlass app to figure it out?
Is there a preferred method for doing this kind of data transfer? Ideally I'd like to transfer data in both directions.

Ok, for the requesters....
EDIT: The code below still works, but I've put it into a git repo for those who are interested...
https://github.com/NathanielWaggoner/GoogleGlassBlutooth
Here is my Bluetooth Host/Client code. It's not perfect - You're going to need some patience, and there are some bugs on reconnection and such, but it does work. I've been sending data up to Glass From the Hand Held and driving UI updates (publishing live cards, updating live cards etc...) for about three days using this now.
Host:
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.UUID;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
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.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;
public class BluetoothHost extends Activity {
public static String msgToSend="";
public static final int STATE_CONNECTION_STARTED = 0;
public static final int STATE_CONNECTION_LOST = 1;
public static final int READY_TO_CONN = 2;
public static final String DEVICE_NAME = "device_name";
public static final String TOAST = "toast";
// our last connection
ConnectedThread mConnectedThread;// = new ConnectedThread(socket);
// track our connections
ArrayList<ConnectedThread> mConnThreads;
// bt adapter for all your bt needs (where we get all our bluetooth powers)
BluetoothAdapter myBt;
// list of sockets we have running (for multiple connections)
ArrayList<BluetoothSocket> mSockets = new ArrayList<BluetoothSocket>();
// list of addresses for devices we've connected to
ArrayList<String> mDeviceAddresses = new ArrayList<String>();
// just a name, nothing more...
String NAME="G6BITCHES";
// We can handle up to 7 connections... or something...
UUID[] uuids = new UUID[2];
// some uuid's we like to use..
String uuid1 = "05f2934c-1e81-4554-bb08-44aa761afbfb";
String uuid2 = "c2911cd0-5c3c-11e3-949a-0800200c9a66";
// just a tag..
String TAG = "G6 Bluetooth Host Activity";
// constant we define and pass to startActForResult (must be >0), that the system passes back to you in your onActivityResult()
// implementation as the requestCode parameter.
int REQUEST_ENABLE_BT = 1;
AcceptThread accThread;
TextView connectedDevices;
Handler handle;
BroadcastReceiver receiver;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// the activity for this is pretty stripped, just a basic selection ui....
setContentView(R.layout.activity_main);
uuids[0] = UUID.fromString(uuid1);
uuids[1] = UUID.fromString(uuid2);
connectedDevices = (TextView) findViewById(R.id.connected_devices_values);
handle = new Handler(Looper.getMainLooper()) {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case STATE_CONNECTION_STARTED:
connectedDevices.setText(msg.getData().getString("NAMES"));
break;
case STATE_CONNECTION_LOST:
connectedDevices.setText("");
startListening();
break;
case READY_TO_CONN:
startListening();
default:
break;
}
}
};
// ....
myBt = BluetoothAdapter.getDefaultAdapter();
// run the "go get em" thread..
accThread = new AcceptThread();
accThread.start();
}
public void startListening() {
if(accThread!=null) {
accThread.cancel();
}else if (mConnectedThread!= null) {
mConnectedThread.cancel();
} else {
accThread = new AcceptThread();
accThread.start();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private class AcceptThread extends Thread {
private BluetoothServerSocket mmServerSocket;
BluetoothServerSocket tmp;
public AcceptThread() {
BluetoothServerSocket tmp = null;
try {
tmp = myBt.listenUsingInsecureRfcommWithServiceRecord(NAME, uuids[0]);
} catch (IOException e) { }
mmServerSocket = tmp;
}
public void run() {
Log.e(TAG,"Running?");
BluetoothSocket socket = null;
// Keep listening until exception occurs or a socket is returned
while (true) {
try {
socket = mmServerSocket.accept();
} catch (IOException e) {
e.printStackTrace();
break;
}
// If a connection was accepted
if (socket != null) {
try {
mmServerSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// Do work to manage the connection (in a separate thread)
manageConnectedSocket(socket);
break;
}
}
}
/** Will cancel the listening socket, and cause the thread to finish */
public void cancel() {
try {
mmServerSocket.close();
Message msg = handle.obtainMessage(READY_TO_CONN);
handle.sendMessage(msg);
} catch (IOException e) { }
}
}
private void manageConnectedSocket(BluetoothSocket socket) {
// start our connection thread
mConnectedThread = new ConnectedThread(socket);
mConnectedThread.start();
// Send the name of the connected device back to the UI Activity
// so the HH can show you it's working and stuff...
String devs="";
for(BluetoothSocket sock: mSockets) {
devs+=sock.getRemoteDevice().getName()+"\n";
}
// pass it to the UI....
Message msg = handle.obtainMessage(STATE_CONNECTION_STARTED);
Bundle bundle = new Bundle();
bundle.putString("NAMES", devs);
msg.setData(bundle);
handle.sendMessage(msg);
}
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
Log.d(TAG, "create ConnectedThread");
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Log.e(TAG, "temp sockets not created", e);
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
int bytes;
// Keep listening to the InputStream while connected
while (true) {
try {
//byte[] blah = ("System Time:" +System.currentTimeMillis()).getBytes();
if(!msgToSend.equals("")) {
Log.e(TAG,"writing!");
write(msgToSend.getBytes());
setMsg("");
}
Thread.sleep(1000);
} catch (Exception e) {
Log.e(TAG, "disconnected", e);
connectionLost();
}
}
}
public void connectionLost() {
Message msg = handle.obtainMessage(STATE_CONNECTION_LOST);
handle.sendMessage(msg);
}
/**
* Write to the connected OutStream.
* #param buffer The bytes to write
*/
public void write(byte[] buffer) {
try {
mmOutStream.write(buffer);
} catch (IOException e) {
Log.e(TAG, "Exception during write", e);
connectionLost();
}
}
public void cancel() {
try {
mmSocket.close();
Message msg = handle.obtainMessage(READY_TO_CONN);
handle.sendMessage(msg);
} catch (IOException e) {
Log.e(TAG, "close() of connect socket failed", e);
}
}
}
public static synchronized void setMsg(String newMsg) {
msgToSend = newMsg;
}
public static class HostBroadRec extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Bundle b= intent.getExtras();
String vals ="";
for(String key: b.keySet()) {
vals+=key+"&"+b.getString(key)+"Z";
}
BluetoothHost.setMsg(vals);
}
}
}
Client:
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Set;
import java.util.UUID;
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 android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
public class BluetoothClient extends Activity {
public static final int READY_TO_CONN =0;
public static final int CANCEL_CONN =1;
public static final int MESSAGE_READ =2;
// holds the bluetooth names/ids that we're associated with.
ArrayAdapter<String> btArray;
// bt adapter for all your bt needs
BluetoothAdapter myBt;
String NAME="G6BITCHES";
String TAG = "G6 Bluetooth Slave Activity";
UUID[] uuids = new UUID[2];
// some uuid's we like to use..
String uuid1 = "05f2934c-1e81-4554-bb08-44aa761afbfb";
String uuid2 = "c2911cd0-5c3c-11e3-949a-0800200c9a66";
// DateFormat df = new DateFormat("ddyyyy")
ConnectThread mConnThread;
Spinner devices;
Handler handle;
// constant we define and pass to startActForResult (must be >0), that the system passes back to you in your onActivityResult()
// implementation as the requestCode parameter.
int REQUEST_ENABLE_BT = 1;
// bc for discovery mode for BT...
private final BroadcastReceiver mReceiver = 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 address to an array adapter to show in a ListView
if(device!= null) {
if(device.getName().contains("Nexus")) {
} else {
btArray.add(device.getName() + "\n" + device.getAddress());
}
}
update();
}
}
};
Context ctx;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// publishCards(this);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
ctx = this;
handle = new Handler(Looper.getMainLooper()) {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case READY_TO_CONN:
mConnThread=null;
update();
break;
case CANCEL_CONN:
break;
case MESSAGE_READ:
byte[] readBuf = (byte[]) msg.obj;
// construct a string from the valid bytes in the buffer
String readMessage = new String(readBuf, 0, msg.arg1);
Log.e(TAG,"received: "+readMessage);
if (readMessage.length() > 0) {
// do soemthing...
}
// updateCards(ctx, readMessage);
// update()
// mConversationArrayAdapter.add(mConnectedDeviceName+": " + readMessage);
break;
default:
break;
}
}
};
btArray = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, android.R.id.text1);
btArray.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
uuids[0] = UUID.fromString(uuid1);
uuids[1] = UUID.fromString(uuid2);
// spinner for displaying available devices for pairing
devices = (Spinner) findViewById(R.id.devices_spinner);
devices.setAdapter(btArray);
// use the same UUID across an installation
// should allow clients to find us repeatedly
myBt = BluetoothAdapter.getDefaultAdapter();
if (myBt == null) {
Toast.makeText(this, "Device Does not Support Bluetooth", Toast.LENGTH_LONG).show();
}
else if (!myBt.isEnabled()) {
// we need to wait until bt is enabled before set up, so that's done either in the following else, or
// in the onActivityResult for our code ...
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
} else {
detectAndSetUp();
}
setContentView(R.layout.bluetooth_activity_layout);
}
#Override
public void onDestroy() {
unregisterReceiver(mReceiver);
super.onDestroy();
}
#Override
protected void onActivityResult (int requestCode, int resultCode, Intent data){
if(requestCode == REQUEST_ENABLE_BT) {
if (resultCode != RESULT_OK) {
Toast.makeText(this, "Failed to enable Bluetooth", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(this, "Bluetooth Enabled", Toast.LENGTH_LONG).show();
detectAndSetUp();
}
}
}
private void detectAndSetUp() {
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter); // Don't forget to unregister during onDestroy
Set<BluetoothDevice> pairedDevices = myBt.getBondedDevices();
// If there are paired devices
if (pairedDevices.size() > 0) {
// Loop through paired devices
for (BluetoothDevice device : pairedDevices) {
if(device.getName().contains("Nexus")) {
} else {
btArray.add(device.getName() + "\n" + device.getAddress());
}
// Add the name and address to an array adapter to show in a ListView
// btArray.add(device.getName() + "\n" + device.getAddress());
// update();
}
}
myBt.startDiscovery();
}
public void update() {
devices = (Spinner) findViewById(R.id.devices_spinner);
devices.setAdapter(btArray);
devices.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1,
int position, long id) {
if(mConnThread!=null) {
Log.e(TAG,"Canceling old connection, and starting new one.");
mConnThread.cancel();
} else {
Log.e(TAG,"got a thing...");
String str = ((TextView)arg1).getText().toString();
Log.e(TAG,"tots: "+str);
String[] vals = str.split("\n");
Log.e(TAG,"mac: "+vals[1]);
BluetoothDevice dev = myBt.getRemoteDevice(vals[1]);
mConnThread = new ConnectThread(dev);
mConnThread.run();
}
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.bluetooth, menu);
return true;
}
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
Log.e(TAG,"ConnectThread start....");
// 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 {
// this seems to work on the note3...
// you can remove the Insecure if you want to...
tmp = device.createInsecureRfcommSocketToServiceRecord(uuids[0]);
// Method m;
// this is an approach I've seen others use, it wasn't nescesary for me,
// but your results may vary...
// m = device.getClass().getMethod("createInsecureRfcommSocket", new Class[] {int.class});
// tmp = (BluetoothSocket) m.invoke(device, 1);
// } catch (NoSuchMethodException e1) {
// // TODO Auto-generated catch block
// e1.printStackTrace();
// } catch (IllegalArgumentException e2) {
// // TODO Auto-generated catch block
// e2.printStackTrace();
// } catch (IllegalAccessException e3) {
// // TODO Auto-generated catch block
// e3.printStackTrace();
// } catch (InvocationTargetException e4) {
// // TODO Auto-generated catch block
// e4.printStackTrace();
// }
// if(tmp.isConnected()) {
// break
// }
} catch (Exception e) {
Log.e(TAG,"Danger Will Robinson");
e.printStackTrace();
}
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it will slow down the connection
myBt.cancelDiscovery();
Log.e(TAG,"stopping discovery");
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
Log.e(TAG,"connecting!");
mmSocket.connect();
} catch (IOException connectException) {
Log.e(TAG,"failed to connect");
// Unable to connect; close the socket and get out
try {
Log.e(TAG,"close-ah-da-socket");
mmSocket.close();
} catch (IOException closeException) {
Log.e(TAG,"failed to close hte socket");
}
Log.e(TAG,"returning..");
return;
}
Log.e(TAG,"we can now manage our connection!");
// Do work to manage the connection (in a separate thread)
manageConnectedSocket(mmSocket);
}
/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmSocket.close();
Message msg = handle.obtainMessage(READY_TO_CONN);
handle.sendMessage(msg);
} catch (IOException e) { }
}
}
public void manageConnectedSocket(BluetoothSocket mmSocket) {
ConnectedThread t = new ConnectedThread(mmSocket);
t.start();
// manage your socket... I'll probably do a lot of the boiler plate here later
}
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
Log.d(TAG, "create ConnectedThread");
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Log.e(TAG, "temp sockets not created", e);
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
int bytes;
// Keep listening to the InputStream while connected
while (true) {
try {
// byte[] blah = ("System Time:" +System.currentTimeMillis()).getBytes();
// write(blah);
// Thread.sleep(1000);
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI Activity
handle.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
// .sendToTarget();
} catch (Exception e) {
Log.e(TAG, "disconnected", e);
connectionLost();
// break;
}
}
}
public void connectionLost() {
Message msg = handle.obtainMessage(CANCEL_CONN);
// Bundle bundle = new Bundle();
// bundle.putString("NAMES", devs);
// msg.setData(bundle);
handle.sendMessage(msg);
}
/**
* Write to the connected OutStream.
* #param buffer The bytes to write
*/
public void write(byte[] buffer) {
try {
mmOutStream.write(buffer);
// Share the sent message back to the UI Activity
// mHandler.obtainMessage(BluetoothChat.MESSAGE_WRITE, -1, -1, buffer)
// .sendToTarget();
} catch (IOException e) {
Log.e(TAG, "Exception during write", e);
}
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect socket failed", e);
}
}
}
}
Host Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="transapps.android_bluetooth_host"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name="transapps.android_bluetooth_host.BluetoothHost"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".BluetoothHost$HostBroadRec" >
<intent-filter>
<action android:name="transapps.g6.new.alert" />
</intent-filter>
</receiver>
</application>
</manifest>
Client Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="transapps.android_blutooth"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name="transapps.android_blutooth.BluetoothClient"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
I'll leave the UI as an exercise to the reader.

There is no preferred method, but if you're looking to do it wirelessly, a Bluetooth 3.0 RFCOMM does work.
If you provide more specifics about the problem you're trying to solve in your question, I'll be able to provide a more specific answer.

Several things I noticed when following this solution (awesome work by the way!)
1) I could only create a bluetooth connection when my phone and the Google Glass were not already paired through the MyGlass app - If you are having trouble establishing a connection, try forgetting that pairing.
2) The Glass API does not support controlling your bluetooth connection through intents using commands like
Intent discoveryIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
discoveryIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, DISCOVER_DURATION);
startActivityForResult(discoveryIntent, REQUEST_BLU);
In order to make the Glass headset discoverable (rather than the phone it is connecting to), I needed to follow solutions similar to those like user4934624 provided at this question and shantanu gave at this question. I invoked a hidden method to access bluetooth functionality directly. Warning: the hidden method seems to have been there for years, but there is no guarantee it will continue to be in future APIs.
// this method allows us to make the device discoverable without alerting the users
// NOTE!!!! This uses a hidden method, so it may be removed from the API in the future
public void makeDiscoverable (){
Class <?> baClass = BluetoothAdapter.class;
Method[] methods = baClass.getDeclaredMethods();
// we want to use method setScanMode(int mode, int duration)
// there are 2 setScanModes
// so select the first setScanMode you see
// test to see which method is the one we want
//for (int i = 0; i<50; i++) {Log.d(Integer.toString(i), methods[i].getName());}
//I had trouble calling the first setScanMode, so I called the second.
// I need to pass in a discoverable time, but it stays discoverable indefinitely
// Thus you must turn off the setScanMode as soon as the connection is established
// I should probably write in some other security stuff to turn it off if connection fails
// maybe a timer running on a different thread?
Method mSetScanMode = methods[38];
try {
mSetScanMode.invoke(myBt, BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE,300);
//mSetScanMode.invoke(myBt, BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE);
} catch (Exception e) {
Log.e("discoverable", e.getMessage());
}
}
// this method allows us to make the device not discoverable without alerting the user
// NOTE!!!! This uses a hidden method, so it may be removed from the API in the future
public void makeNotDiscoverable (){
// see notes for makeDiscoverable
Class <?> baClass = BluetoothAdapter.class;
Method [] methods = baClass.getDeclaredMethods();
Method mSetScanMode = methods[38];
try {
mSetScanMode.invoke(myBt, BluetoothAdapter.SCAN_MODE_CONNECTABLE,300);
} catch (Exception e) {
Log.e("discoverable", e.getMessage());
}
}
Note that I first ran a test that output the names of all the methods in the class I mirrored; that allowed me to narrow my search for which method I wanted to use.

The JoeGlass app for android claims to be a replacement for MyGlass. It will talk to your glass directly, using a bluetooth connection. I have not tried yet it but it is open source (github), so if it works, you are good.

My book Beginning Google Glass Development has a full chapter on this topic, with fully working example code on using Bluetooth and socket to transfer data between Glass and Android (or iOS) devices.
The book is available at amazon: http://www.amazon.com/Beginning-Google-Glass-Development-Jeff/dp/1430267887
and the source code is available for download at http://www.apress.com/downloadable/download/sample/sample_id/1562/

Bind Socket Android

I have a problem on android. I have an application that asks the user for the local Ip address (from the device's interface) and another remote address. The application has to bind to the specified local address and connect to the remote address. Quite simple, but, indeed, bind does not work ass i expected..
I added the following permissions on the manifest file:
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
The source code is the following one:
public class MainActivity extends Activity
{
String Tag = "TAG";
private int LOCAL_PORT = 4444;
private int REMOTE_PORT = 80;
private EditText LOCAL;
private EditText REMOTE;
private Button Connect;
private TextView STATUS;
private Context context = this;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LOCAL = (EditText) findViewById(R.id.editText1);
REMOTE = (EditText) findViewById(R.id.editText2);
Connect = (Button) findViewById(R.id.button1);
Connect.setOnClickListener(new View.OnClickListener() {
public void onClick(View v)
{
BotleneckHandle WORK;
Toast.makeText(getApplicationContext(), "Proceeding to connect",
Toast.LENGTH_SHORT).show();
/*
if(LOCAL.getText().toString() == null || REMOTE.getText().toString() == null || LOCAL.getText().toString().equals(" ") || REMOTE.getText().toString().equals(" ") || LOCAL.getText().toString().equals("") || REMOTE.getText().toString().equals(""))
Toast.makeText(context, "Wrong parameters", 2000);
else
{
Toast.makeText(getApplicationContext(), "Proceeding to connect",Toast.LENGTH_SHORT).show();
}*/
WORK = new BotleneckHandle();
WORK.execute();
}
});
STATUS = (TextView) findViewById(R.id.textView1);
}
private class BotleneckHandle extends AsyncTask <Void , Void , String>
{
Socket Skt = null;
String ReturnStatemente = new String();
SocketAddress localAddr = new InetSocketAddress(LOCAL.getText().toString(), LOCAL_PORT);
protected void onPreExecute(){ }
protected String doInBackground(Void... params)
{
try
{
String s=new String();
s+= "Local="+LOCAL.getText().toString()+":"+LOCAL_PORT+" Remote="+REMOTE.getText().toString()+":"+REMOTE_PORT; //so far so good, Confirmed by debug
Toast.makeText(getApplicationContext(), s,Toast.LENGTH_SHORT).show(); //Does not show anything due the fact that i didn't published it as an assync task update..
//binding to a local address
Skt.bind(localAddr); //cannot make the bind :-/
//connecting to remote host
Skt=new Socket(REMOTE.getText().toString(), REMOTE_PORT); //if bind is comment, still does not work.. I bet
ReturnStatemente = "Connected";
}
catch (UnknownHostException e)
{
e.printStackTrace();
Toast.makeText(context, "Unknown remote host", 2000);
ReturnStatemente = "Not Connected";
}
catch (IOException e)
{
e.printStackTrace();
Toast.makeText(context, "Connection fail", 2000);
ReturnStatemente = "Not Connected";
}
finally{try {
Skt.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}}
return ReturnStatemente;
}
protected void onPostExecute(String result) { STATUS.setText(" CONECTION STATUS == " + result); }
}
}
What am i doing wrong on bind? As far as i see, and as i searched for its good.. Did i miss something?
kind regards

You're trying to call bind on a variable before you assigned anything to it. So its still null. That isn't going to work. You need to create an instance of Socket before you can call methods on it.

Can't get bluetooth Adapter in Android

I was trying to implement the bluetooth chat example given in the android samples.
I am running it on a jelly beans device which has Android 4.1 version running on it .
The application simply force closes. A part of launcher activity code of launcher activity goes like this.
WHEN I COMMENT THE LINE "mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();" THE APPLICATION DOES NOT FORCE CLOSE. and all the toast messages are also displayed which are not with the line uncommented
private BluetoothAdapter mBluetoothAdapter = null;
// Member object for the chat services
private BluetoothChatService mChatService = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Toast.makeText(getApplicationContext(),"BluetothChat oncreate()", Toast.LENGTH_LONG).show();
if(D) Log.e(TAG, "+++ ON CREATE +++");
// Set up the window layout
setContentView(R.layout.main);
// Get local Bluetooth adapter
try {
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
//}
// If the adapter is null, then Bluetooth is not supported
if (mBluetoothAdapter == null) {
Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show();
finish();
return;
}
} catch (Exception e) {
Toast.makeText(this,e.toString(), Toast.LENGTH_LONG).show();
}
}
#Override
public void onStart() {
Toast.makeText(getApplicationContext(),"BluetothChat onstart()", Toast.LENGTH_LONG).show();
super.onStart();
if(D) Log.e(TAG, "++ ON START ++");
// If BT is not on, request that it be enabled.
// setupChat() will then be called during onActivityResult
try {
if (!mBluetoothAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
// Otherwise, setup the chat session
} else {
if (mChatService == null) {
setupChat();
}
}
} catch (Exception e) {
Toast.makeText(this,e.toString(), Toast.LENGTH_LONG).show();
}
}

Android bluetooth application process killed

I'm very new with programming for android. I have two classes : main and btmanager. When i try to test my app on phone, all I get is a information that procees was killed. What am I doing wrong ?
Code implementation :
Main class :
public class MainActivity extends Activity {
BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();
Btmanager manager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (bluetooth == null)
{
Toast.makeText(this, "Bluetooth is not enabled on this device", Toast.LENGTH_LONG).show();
System.exit(0);
}
}
#Override
public void onStart()
{
super.onStart();
if (!bluetooth.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 2);
}
manager.run();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void closeApp (View view)
{
System.exit(0);
}
}
Btmanager class :
public class Btmanager extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public static final UUID myUUID = UUID.fromString("0x1101");
BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();
public Btmanager(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(myUUID);
} catch (IOException e) { }
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it will slow down the connection
bluetooth.cancelDiscovery();
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mmSocket.connect();
} catch (IOException connectException) {
// Unable to connect; close the socket and get out
try {
mmSocket.close();
} catch (IOException closeException) { }
return;
}
}
/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}

2 problems I see in your code:
You don't instantiate the Btmanager object, it is still null when you call run. (Will cause a NullPointerException - your app will crash).
You call the run method instead of the start method of the Btmanager. If you want the code in the run method to run in a new thread, you have to call start. Calling run will cause it to run in the same thread. This blocks your UI thread which may cause your app to crash, if it blocks for too long.

For test purporses, I don't use BTmanager class - in onStart() method I add new thread with connection implentation, but still without any results - app crash.
public void onStart()
{
super.onStart();
if (!bluetooth.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 2);
}
new Thread(new Runnable()
{
public void run()
{
try {
//Create a Socket connection: need the server's UUID number of registered
socket = device.createRfcommSocketToServiceRecord(myUUID);
socket.connect();
Log.d("EF-BTBee", "Connectted");
}
catch (IOException e)
{
Log.e("EF-BTBee", "Error : ", e);
}
}
}).start();
}