Develop Reference

Bluetooth Android - Arduino App Error - java.lang.IllegalArgumentException: null is not a valid Bluetooth address

I need your help!
First: I am from austria , so my english is not so good. So I apologize for the mistakes I will make!
This is my first project I try with Android Studio. I am a newbie in programming. I have not much skill in Arduino and Android program language, but I need it for my bachelor project, so I have to learn it!
I worked with a tutorial video, which was in spanish, so I have no clue what that guy was talking about, but I understood the code all in all.
My problem is, when I start the app on my phone, the first screen (paired devices) works fine. But when I press on the paired device...
This following error occurs :
Capturing and displaying logcat messages from application. This
behavior can be disabled in the "Logcat output" section of the
"Debugger" settings page. D/OpenGLRenderer:
ProgramCache.generateProgram: 103079215104 D/AndroidRuntime: Shutting
down VM E/AndroidRuntime: FATAL EXCEPTION: main
Process: bachelor_projekt.bluetoothcontroller, PID: 11061
java.lang.RuntimeException: Unable to resume activity
{bachelor_projekt.bluetoothcontroller/bachelor_projekt.bluetoothcontroller.UserInterface}:
java.lang.IllegalArgumentException: null is not a valid Bluetooth
address
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3506)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3546)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2795)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6247)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
Caused by: java.lang.IllegalArgumentException: null is not a valid Bluetooth address
at android.bluetooth.BluetoothDevice.(BluetoothDevice.java:668)
at android.bluetooth.BluetoothAdapter.getRemoteDevice(BluetoothAdapter.java:553)
at bachelor_projekt.bluetoothcontroller.UserInterface.onResume(UserInterface.java:122)
at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1272)
at android.app.Activity.performResume(Activity.java:6917)
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3477)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3546) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2795) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527) 
at android.os.Handler.dispatchMessage(Handler.java:110) 
at android.os.Looper.loop(Looper.java:203) 
at android.app.ActivityThread.main(ActivityThread.java:6247) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924) 
I/Process: Sending signal. PID: 11061 SIG: 9 Application terminated.
After that message, the app shuts down :
I divided my app in:
Bluetooth - for the bluetooth connection
Here is the code:
package bachelor_projekt.bluetoothcontroller;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
import java.util.Set;
public class Bluetooth extends AppCompatActivity {
// Cleaning of the Logcat (Systemlog)
private static final String TAG = "Bluetooth";
// Declaration of ListView
ListView IdList;
// String which will be sended to the main frame
public static String EXTRA_DEVICE_ADDRESS = "device_address";
// Declaration of the fields
private BluetoothAdapter myBluetooth;
private ArrayAdapter<String> myPairedDevicesArray;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bluetooth);
}
#Override
public void onResume()
{
super.onResume();
//----------------------------
VerificationBT();
// Initialze the array which keeps the bluetooth devices
myPairedDevicesArray=new ArrayAdapter<String>(this, R.layout.device_name);
IdList = findViewById(R.id.idList);
IdList.setAdapter(myPairedDevicesArray);
IdList.setOnItemClickListener(myDeviceClickListener);
// Get local default bluetooth adapter
myBluetooth = BluetoothAdapter.getDefaultAdapter();
// Includes the bluetooth member which is paired with the device
Set<BluetoothDevice> pairedDevices =myBluetooth.getBondedDevices();
// Pair with an already in the array included device.
if (pairedDevices.size()>0)
{
for (BluetoothDevice device : pairedDevices){
myPairedDevicesArray.add(device.getName() + "\n" + device.getAddress());
}
}
}
// Configuration for the "on click" ability for the liste
private AdapterView.OnItemClickListener myDeviceClickListener = new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView av , View v, int arg2, long arg3) {
// Detect the MAC-Adress of the device ( last 17 caracters)
String info = ((TextView) v).getText().toString();
String address = info.substring(info.length() - 17);
// 1 Try to connect if MAC adress is the same
Intent i = new Intent(Bluetooth.this, UserInterface.class);
startActivity(i);
}
};
private void VerificationBT(){
// Checks if the device has bluetooth and if it is activated
myBluetooth=BluetoothAdapter.getDefaultAdapter();
if(myBluetooth==null) {
Toast.makeText(getBaseContext(), "Device doesn't have bluetooth", Toast.LENGTH_SHORT).show();
} else{
if (myBluetooth.isEnabled()) {
Log.d(TAG, "...Bluetooth Avtivated...");
} else{
// Ask the user to activate bluetooth
Intent enableBt = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBt,1);
}
}
}
}
The second part is the user interface - Here should be the actual project which is just for start (3 Buttons, 1 for LED on, 1 for LED off, 1 for disconnect).
Here is the code:
package bachelor_projekt.bluetoothcontroller;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
public class UserInterface extends AppCompatActivity {
Button IdLedON, IdLedOFF, IdDisconnect;
TextView IdBuffer;
//-------------------------------------------------
Handler bluetoothIn;
final int handlerState = 0;
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private StringBuilder DataStringIN = new StringBuilder();
private ConnectedThread MyConnection;
// Special service - SPP UUID
private static final UUID BTMODULE_UUID = UUID.fromString
("00001101-0000-1000-8000-00211300ACCD"); //805F9B34FB
// String direction of the MAC
private static String address = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_user_interface);
// Connection between inferface and variables
IdLedON = (Button) findViewById(R.id.IdLedON);
IdLedOFF = (Button) findViewById(R.id.IdLedOFF);
IdDisconnect = (Button) findViewById(R.id.IdDisconnect);
IdBuffer = findViewById(R.id.IdBuffer);
bluetoothIn = new Handler(){
public void handleMessage(android.os.Message msg){
if (msg.what == handlerState) {
String readMessage = (String) msg.obj;
DataStringIN.append(readMessage);
int endOfLineIndex = DataStringIN.indexOf("#");
if (endOfLineIndex > 0) {
String dataInPrint = DataStringIN.substring(0, endOfLineIndex);
IdBuffer.setText("Data: " + dataInPrint);
DataStringIN.delete(0, DataStringIN.length());
}
}
}
};
btAdapter = BluetoothAdapter.getDefaultAdapter();
VerificationBT();
IdLedON.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
MyConnection.write("1");
}
});
IdLedOFF.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
MyConnection.write("0");
}
});
IdDisconnect.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (btSocket != null)
{
try {
btSocket.close();
} catch (IOException e) {
Toast.makeText(getBaseContext(), "Error", Toast.LENGTH_SHORT).show();;}
}
finish();
}
});
}
private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException
{
// Creates a save Connection for the device
return device.createRfcommSocketToServiceRecord(BTMODULE_UUID);
}
#Override
public void onResume()
{
super.onResume();
// Receives MAC Adress Direction out of DeviceListActivity via intent
Intent intent = getIntent();
// Receives MAC Adress Direction out of DeviceListActivity via EXTRA
address = intent.getStringExtra(Bluetooth.EXTRA_DEVICE_ADDRESS);
// adjust MAC Adress
BluetoothDevice device = btAdapter.getRemoteDevice(address);
try
{
btSocket = createBluetoothSocket(device);
} catch (IOException e) {
Toast.makeText(getBaseContext(), "Error while Connection with device accured ", Toast.LENGTH_SHORT).show();
}
// Creates a connection with bluetooth
try
{
btSocket.connect();
} catch (IOException e){
try{
btSocket.close();
} catch (IOException e2){}
}
MyConnection = new ConnectedThread(btSocket);
MyConnection.start();
}
#Override
public void onPause()
{
super.onPause();
try
{
// If you leave the application there can be no access to the bluetooth adapter
btSocket.close();
} catch (IOException e2){}
}
// Check if bluetooth device is available and connect with it
private void VerificationBT()
{
if (btAdapter == null) {
Toast.makeText(getBaseContext(), "Device doesn't support bluetooth", Toast.LENGTH_LONG);
} else {
Intent enableBt = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBt, 1);
}
}
// class for making a connection
private class ConnectedThread extends Thread
{
private final InputStream myInStream;
private final OutputStream myOutStream;
public ConnectedThread(BluetoothSocket socket)
{
InputStream tmpIn=null;
OutputStream tmpOut=null;
try
{
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {}
myInStream=tmpIn;
myOutStream=tmpOut;
}
public void run()
{
byte[] buffer = new byte[256];
int bytes;
// Device stays in the "try to connect" mode
while(true) {
try {
bytes = myInStream.read(buffer);
String readMessage = new String(buffer, 0, bytes);
} catch (IOException e) {
break;
}
}
}
public void write(String input)
{
try{
myOutStream.write(input.getBytes());
} catch (IOException e)
{
// If it is not possible to send data
Toast.makeText(getBaseContext(), " Connection failed", Toast.LENGTH_LONG).show();
finish();
}
}
}
}
So if you need for information, just tell me.
Hopefully someone of you understands my problem and can help me :)
Best wishes
Semi

Seems like there is an error in the code.
This error:
android.app.ActivityThread.handleResumeActivity
Appeared way too many times which means and activity froze or crashed and then tried to restart but kept on failing so many times it just gave up in the end.
Also, it looks like your using a VM to test the code so try using it with a real device.
If you cant find out the problem try writing the code from the start again or run it through a bug interpreter.
Best of luck,
Paul!

Android's bluetooth BluetoothDevice.ACTION_FOUND is not being triggered?

I'm trying to manage several Bluetooth events from my app so the user will not need to leave the app & try to search/pair Bluetooth devices from Android settings.
I'm able to enumerate previously paired devices, and start discovery, however I cant find nearby devices.
Background info:
Device = Samsung Galaxy S6
OS = Android 6.0.1 , Kernel 3.4.0-750027
Bluetooth devices are visible via Android's own built in discovery
Here is my relevant code:
package experiment.xyz.abc;
import android.app.ListActivity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
/**
*
* This activity is responsible for bluetooth device discovery, pairing, and selection.
* 1) user can search for nearby devices
* 2) pair with device
* 3) unpair a device
* 4) select a bt device( upon successful selection the activity navigates away).
*/
public class BluetDeviceListActivity extends ListActivity
{
public static String BLUETOOTH_DEVICE_ADDRESS= "BLUETOOTH_DEVICE_ADDRESS";
List<BluetoothDevice> bluetList;
BluetoothDeviceListAdapter newBluetoothDeviceListAdapter = null;
private Set<BluetoothDevice> pairedDevices;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.bluet_list_view);
//instantiate adapter
newBluetoothDeviceListAdapter = new BluetoothDeviceListAdapter(this);
//populate bluet list
populatePairedBluetoothDevices();
//set the ListActivity's adapter with our custom adapter
setListAdapter(newBluetoothDeviceListAdapter);
//on item click get the associated item based index & use Intent to send BluetoothDevice
getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
BluetoothDevice bluetoothDevice= newBluetoothDeviceListAdapter.getListOfBluetoothDevices().get(position);
if (bluetoothDevice!=null) {
Intent returnIntent = new Intent();
returnIntent.putExtra(BLUETOOTH_DEVICE_ADDRESS, bluetoothDevice.getAddress());
setResult(RESULT_OK, returnIntent);
}
finish();
if (mReceiver!=null)
{
try {
unregisterReceiver(mReceiver);
}
catch (IllegalArgumentException exc)
{
exc.printStackTrace();
}
}
}
});
//cancel activity dialog
Button cancelButton = (Button) findViewById(R.id.cancelBluetoothDialogButton);
cancelButton.setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
if (mReceiver!=null)
{
try {
unregisterReceiver(mReceiver);
}
catch (IllegalArgumentException exc)
{
exc.printStackTrace();
}
}
}
});
//search for bluetooth devices
Button searchAndPairButton = (Button) findViewById(R.id.searchPairButton);
searchAndPairButton.setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(View v) {
//update textview
populateDiscoveredBluetoothDevices();
}
});
//pair or unpair selected device
Button pairOrUnpairButton = (Button) findViewById(R.id.pairUnpairDialogButton);
pairOrUnpairButton.setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(View v) {
//TODO:
}
});
}//end onCreate
//discover nearby devices & add to list
private void populateDiscoveredBluetoothDevices()
{
StreamApiUtility.getBluetoothAdapter();
//is bluet enabled
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter != null && mBluetoothAdapter.isEnabled()) {
//if already discovering cancel
if(mBluetoothAdapter.isDiscovering()){
mBluetoothAdapter.cancelDiscovery();
}
//start a new discovery
mBluetoothAdapter.startDiscovery();
}//end there are paired devices
else
{
Log.i("EEGdataCapture", "No paired devices, select Search & Pair.");
TextView textView =(TextView) findViewById(R.id.textViewBluetoothListInstruction);
textView.setText("No paired devices, select Search & Pair.");
}
}
//query already paired & add to list
private void populatePairedBluetoothDevices()
{
StreamApiUtility.getBluetoothAdapter();
//is bluet enabled
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter != null && mBluetoothAdapter.isEnabled()) {
//if already discovering cancel
if(mBluetoothAdapter.isDiscovering()){
mBluetoothAdapter.cancelDiscovery();
}
//start a new discovery
mBluetoothAdapter.startDiscovery();
//iterate paired/bonded devices and if there are any add them to the custom adapter
pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
BluetoothDevice bluetoothDevice;
Iterator<BluetoothDevice> it = pairedDevices.iterator();
while (it.hasNext()) {
bluetoothDevice = (BluetoothDevice) it.next();
//add to adapter
newBluetoothDeviceListAdapter.addDevice(bluetoothDevice);
newBluetoothDeviceListAdapter.notifyDataSetChanged();
Log.i("EEGdataCapture", "paired device, name: " + bluetoothDevice.getName() + ", address: " + bluetoothDevice.getAddress());
}
}//end there are paired devices
else
{
Log.i("EEGdataCapture", "No paired devices, select Search & Pair.");
TextView textView =(TextView) findViewById(R.id.textViewBluetoothListInstruction);
textView.setText("No paired devices, select Search & Pair.");
}
}
}
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
BluetoothDevice device;
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Log.i("EEGdataCapture", "BluetoothDevice.ACTION_FOUND");
Log.i("EEGdataCapture", device.getName() + "\n" + device.getAddress());
//update list
newBluetoothDeviceListAdapter.addDevice(device);
newBluetoothDeviceListAdapter.notifyDataSetChanged();
}
else if (BluetoothDevice.ACTION_BOND_STATE_CHANGED.equals(action)) {
Log.i("EEGdataCapture", "BluetoothDevice.ACTION_BOND_STATE_CHANGED");
final int state = intent.getIntExtra(BluetoothDevice.EXTRA_BOND_STATE, BluetoothDevice.ERROR);
final int prevState = intent.getIntExtra(BluetoothDevice.EXTRA_PREVIOUS_BOND_STATE, BluetoothDevice.ERROR);
if (state == BluetoothDevice.BOND_BONDED && prevState == BluetoothDevice.BOND_BONDING) {
Toast.makeText(MyApp.getAppContext(), "Paired", Toast.LENGTH_SHORT).show();
} else if (state == BluetoothDevice.BOND_NONE && prevState == BluetoothDevice.BOND_BONDED) {
Toast.makeText(MyApp.getAppContext(), "Unpaired", Toast.LENGTH_SHORT).show();
}
}
else if (BluetoothDevice.ACTION_UUID.equals(action)) {
Log.i("EEGdataCapture", "BluetoothDevice.ACTION_UUID");
}
else if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
Log.i("EEGdataCapture", "BluetoothAdapter.ACTION_DISCOVERY_STARTED, Discovery Started...");
}
else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
Log.i("EEGdataCapture", "BluetoothAdapter.ACTION_DISCOVERY_FINISHED, Discovery finished.");
}
else
{
Log.i("EEGdataCapture", "BluetoothAdapter, ACTIOM is not supported, action ="+action);
}
}};
private void pairDevice(BluetoothDevice device) {
try {
Method method = device.getClass().getMethod("createBond", (Class[]) null);
method.invoke(device, (Object[]) null);
} catch (Exception e) {
e.printStackTrace();
}
}
private void unpairDevice(BluetoothDevice device) {
try {
Method method = device.getClass().getMethod("removeBond", (Class[]) null);
method.invoke(device, (Object[]) null);
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
protected void onPause() {
super.onPause();
if ( StreamApiUtility.getBluetoothAdapter()!=null) {
StreamApiUtility.getBluetoothAdapter().cancelDiscovery();
}
if (mReceiver!=null)
{
try {
unregisterReceiver(mReceiver);
}
catch (IllegalArgumentException exc)
{
exc.printStackTrace();
}
}
}
#Override
protected void onResume()
{
super.onResume();
//filter to capture bluet events
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothDevice.ACTION_UUID);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
//register listener for bluet events before starting discovery again
registerReceiver(mReceiver, filter);
}
#Override
protected void onDestroy() {
super.onDestroy();
if (mReceiver!=null)
{
try {
unregisterReceiver(mReceiver);
}
catch (IllegalArgumentException exc)
{
exc.printStackTrace();
}
}
}
}
updated Manifest:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
The BroadcastReciever's BluetoothDevice.ACTION_FOUND is not being triggered/called although ACTION_DISCOVERY_STARTED OR ACTION_DISCOVERY_FINISHED are being called.
Help please???
Thanks

Your code seems ok. I guess you have the BLUETOOTH permission (otherwise you wouldn't receive the ACTION_DISCOVERY_STARTED) but do you also have the ACCESS_COARSE_LOCATION permission ?
You need it to receive ACTION_FOUND :
ACTION_FOUND
Broadcast Action: Remote device discovered.
Requires BLUETOOTH and ACCESS_COARSE_LOCATION to receive.

You need to perform a realtime-Permission check to ensure that Coarse Location is enabled before discovering any devices.
To do this, you should be targeting/minimum SDK 23+ in your build.gradle file.
if (mActivityContext.checkSelfPermission("android.permission.ACCESS_COARSE_LOCATION") == PackageManager.PERMISSION_GRANTED) {
final BluetoothManager bluetoothManager =
(BluetoothManager) mActivityContext.getSystemService(Context.BLUETOOTH_SERVICE);
if (bluetoothManager != null) mBleAdapter = bluetoothManager.getAdapter();
Register Intent Filters here
mBleAdapter.startDiscovery();
} else {
mInterface.requestPermission(Manifest.permission.ACCESS_COARSE_LOCATION, mCoarsePermissionTag);
}
mInterface is my interface back to my MainActivity

Android BLE is connecting to multiple devices at once

I've seen plenty of questions about how to connect to multiple devices purposely. But in my situation, I am only trying to connect to one hardware device.
I have two hardware devices that are supposed to do the same thing. When they connect to my app via BLE, then they have an LED that turns a solid color. This all works fine and dandy when I only have one device turned on. However, when I turn two of the devices on and then try to connect to just one. Both of the devices' LED's turn solid. Although I don't seem to be getting any incoming data from the one that I didn't intend to connect to.
I don't think it's the device's fault. Because I don't have this issue on iOS. I think the phone might be remembering previously connected devices somewhere maybe?
I'm sorry, this is a lot of code. But I feel like it's important to have this whole class. Any help is much appreciated.
package com.roberts.croberts.orange;
import android.annotation.TargetApi;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.BluetoothProfile;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanResult;
import android.content.Context;
import android.os.Build;
import android.os.Handler;
import android.util.Log;
import android.bluetooth.le.BluetoothLeScanner;
import java.util.ArrayList;
import java.util.List;
#TargetApi(21)
public class BluetoothRegulator {
private static BluetoothRegulator instance = null;
private Context context;
private BluetoothLeScanner mLEScanner;
private BluetoothDevice orangeDevice;
//scanner stuff
private Handler mHandler;
// Stops scanning after 3 seconds.
private static final long SCAN_PERIOD = 3000;
//connected stuff
private android.bluetooth.BluetoothManager mBluetoothManager;
private BluetoothAdapter mBluetoothAdapter;
private BluetoothGatt mBluetoothGatt;
public ArrayList<BluetoothDevice> devices = new ArrayList<>();
private Handler foundHandler = new Handler();
private Handler servicesHandler = new Handler();
private ScanCallback mScanCallback;
public static BluetoothRegulator sharedInstance(){
if(instance == null) {
instance = new BluetoothRegulator();
Log.i("chase", "created new instance");
}
return instance;
}
// Implements callback methods for GATT events that the app cares about. For example,
// connection change and services discovered.
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
if (newState == BluetoothProfile.STATE_CONNECTED) {
mBluetoothGatt.discoverServices();
Log.i(TAG, "BR: onconnectionsStateChanged Connected to GATT server.");
// Attempts to discover services after successful connection.
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
Log.i(TAG, "Disconnected from GATT server.");
}
}
#Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
// Loops through available GATT Serviceokay so ees.
for (BluetoothGattService gattService : mBluetoothGatt.getServices()) {
for (BluetoothGattCharacteristic gattCharacteristic : gattService.getCharacteristics()) {
mBluetoothGatt.setCharacteristicNotification(gattCharacteristic, true);
Log.i(TAG, mBluetoothGatt == null ? "mbluetooth is null" : "should be subscribed");
}
}
Log.i("chase", "did connect and discover devices");
} else {
Log.w(TAG, "Not Success onServicesDiscovered received: " + status);
connect(orangeDevice);
}
}
private Object getFieldFromObject(Object obj, String name){
try {
Field field = obj.getClass().getDeclaredField(name);
field.setAccessible(true);
return field.get(obj);
}catch(Exception e){
Log.i("chase", "e: "+e);
return null;
}
}
#Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
Log.i("BR: chase", "received data!");
}
};
public void close() {
if (mBluetoothGatt == null) {
return;
}
mBluetoothGatt.close();
mBluetoothGatt = null;
}
public boolean initialize(android.bluetooth.BluetoothManager btmanager, Context ctx) {
mBluetoothManager = btmanager;
context = ctx;
mBluetoothAdapter = mBluetoothManager.getAdapter();
if (mBluetoothAdapter == null) {
Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
return false;
}
if (Build.VERSION.SDK_INT >= 21) {
mLEScanner = mBluetoothAdapter.getBluetoothLeScanner();
setUpCallBack();
}
return true;
}
public void scan() { //we call scan when they hit the connect button...
// Stops scanning after a pre-defined scan period.
Log.i("chase", "start scanning");
devices = new ArrayList<>();
if (mHandler == null) mHandler = new Handler();
mHandler.postDelayed(new Runnable() {
#Override
public void run() {
if (Build.VERSION.SDK_INT < 21) {
mBluetoothAdapter.stopLeScan(mLeScanCallback);
} else {
mLEScanner.stopScan(mScanCallback);
}
}
}, SCAN_PERIOD);
if (Build.VERSION.SDK_INT < 21) {
mBluetoothAdapter.startLeScan(mLeScanCallback);
} else {
mLEScanner.startScan(mScanCallback);
}
}
private void foundDevice(BluetoothDevice device){
final String deviceName = device.getName();
if (deviceName != null && deviceName.length() > 5 && (deviceName.substring(0, 6).equals("orange") || deviceName.substring(0, 6).equals("smartb"))) {
for (BluetoothDevice d : devices){
if (d.getAddress().equals(device.getAddress())){
return;
}
}
mHandler.removeCallbacksAndMessages(null);
devices.add(device);
if (devices.size() == 1) { //wait one second and then assume there aren't any more devices named "orange"
foundHandler.postDelayed(new Runnable() {
public void run() {
doneSearching();
}
}, 1000);
}
}
}
private void doneSearching(){
if (Build.VERSION.SDK_INT < 21) {
mBluetoothAdapter.stopLeScan(mLeScanCallback);
} else {
mLEScanner.stopScan(mScanCallback);
}
if (devices.size() == 1){
BluetoothDevice device = devices.get(0);
connect(device);
}else{
//normally this displays a list and the user can choose which device. But this works just as well for now.
BluetoothDevice device = devices.get(0);
connect(device);
}
}
//connect method
public boolean connect(BluetoothDevice btdevice) {
orangeDevice = btdevice;
if (mBluetoothAdapter == null || btdevice == null || btdevice.getAddress() == null) {
return false;
}
if (Build.VERSION.SDK_INT < 21) {
mBluetoothAdapter.stopLeScan(mLeScanCallback);
} else {
mLEScanner.stopScan(mScanCallback);
}
devices = new ArrayList<>();
mBluetoothGatt = orangeDevice.connectGatt(context, true, mGattCallback);
return true;
}
public void disconnect() {
if (mBluetoothAdapter == null || mBluetoothGatt == null) return;
mBluetoothGatt.disconnect();
mBluetoothGatt = null;
}
// Device scan callback.
private BluetoothAdapter.LeScanCallback mLeScanCallback =
new BluetoothAdapter.LeScanCallback() {
#Override
public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
foundDevice(device);
}
};
public void setUpCallBack(){
mScanCallback = new ScanCallback() {
#Override
public void onScanResult(int callbackType, ScanResult result) {
BluetoothDevice device = result.getDevice();
foundDevice(device);
}
#Override
public void onScanFailed(int errorCode) {
Log.e("Chase", "Scan Failed Error Code: " + errorCode);
}
};
}
}
Update
I was playing around with a galaxy tablet and wasn't able to recreate the issue. So I think it's device dependent. The problem occurs on the Galaxy S3, and I am trying to round up some other devices to test with.
Also, I was able to get my hands on some new devices and it seems that if the device has never been connected before to the phone (virgin device) then that device doesn't get mixed up and think it's connected when it's not. So we will see it when we search but it never thinks I am connecting to it, until I actually do connect to it. After that, then half the time it thinks I am trying to talk to it when I am not. I hope that makes sense. Which backs up the theory that the phone is somehow caching old devices. I tried uninstalling the app and reinstalling it to see if it would have the same effect as using a virgin device, but it seems the app has nothing to do with it. The device will still connect (when it's not supposed to) after it has been introduced to the phone, even if I did a fresh install of the app.

I would check the BLE devices themselves. Is there a chance that they might have the same System ID ? I believe it's the first characteristic in 0x180A. If so - it will be difficult for the host to distinguish them and such a double connection might happen.

-Lets say you have 2 devices. So foundDevice() gets called. Now devices arraylist contains 1 device.
-After that you are using handler which calls doneSearching() & checks
if device.size()==1
It returns true and you call connect()
-Inside connect you are again creating an arraylist i.e
devices = new ArrayList<>();
So what happens now is your devices ArrayList<>() contains 0 elements.
-So now when 2nd device is found again the above steps are repeated because whenever connect method is getting called, the size of list is getting refreshed to 0
So just remove the line
devices = new ArrayList<>();
inside connect() method

Sending data from Android to Arduino with HC-06 Bluetooth module

I've created an Android app to communicate with my Arduino using Bluetooth. But when I'm sending data from my Android device to my Arduino, the Arduino isn't responding to what I've send. I am able to get a connection from my Android device to my Arduino. So that's not the problem.
Here's my full script for Android.
package nl.handoko.LumaMini;
import java.io.IOException;
import java.io.OutputStream;
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.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final String TAG = "LumaMini";
private static final int REQUEST_ENABLE_BT = 1;
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private OutputStream outStream = null;
Button fourty, thirty, twenty, twelve, automatic, manual;
TextView message;
// Well known SPP UUID
private static final UUID MY_UUID =
UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// Server's MAC address
private static String address = "98:D3:31:30:09:43";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, "In onCreate()");
setContentView(R.layout.activity_mainnn);
fourty = (Button) findViewById(R.id.button1);
thirty = (Button) findViewById(R.id.button4);
twenty = (Button) findViewById(R.id.button2);
twelve = (Button) findViewById(R.id.button5);
automatic = (Button) findViewById(R.id.button3);
manual = (Button) findViewById(R.id.button6);
message = (TextView) findViewById(R.id.textView1);
fourty.setText("40 Leds");
thirty.setText("30 Leds");
twenty.setText("20 Leds");
twelve.setText("12 Leds");
automatic.setText("Automatic");
manual.setText("Manual");
message.setText("Using this app you can take full control of the Luma Mini!" +
"When it's running on automatic please switch back to manual first before switching to other versions.");
btAdapter = BluetoothAdapter.getDefaultAdapter();
checkBTState();
fourty.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("a");
Toast msg = Toast.makeText(getBaseContext(),
"40 Leds version", Toast.LENGTH_SHORT);
msg.show();
}
});
thirty.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("b");
Toast msg = Toast.makeText(getBaseContext(),
"30 Leds version", Toast.LENGTH_SHORT);
msg.show();
}
});
twenty.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("c");
Toast msg = Toast.makeText(getBaseContext(),
"20 Leds version", Toast.LENGTH_SHORT);
msg.show();
}
});
twelve.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("d");
Toast msg = Toast.makeText(getBaseContext(),
"12 Leds version", Toast.LENGTH_SHORT);
msg.show();
}
});
automatic.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("e");
Toast msg = Toast.makeText(getBaseContext(),
"Run automatically", Toast.LENGTH_SHORT);
msg.show();
}
});
manual.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("f");
Toast msg = Toast.makeText(getBaseContext(),
"Manually switch Leds", Toast.LENGTH_SHORT);
msg.show();
}
});
}
#Override
public void onResume() {
super.onResume();
Log.d(TAG, "...In onResume - Attempting client 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 = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
}
// Discovery is resource intensive. Make sure it isn't going on
// when you attempt to connect and pass your message.
btAdapter.cancelDiscovery();
// Establish the connection. This will block until it connects.
Log.d(TAG, "...Connecting to Remote...");
try {
btSocket.connect();
Log.d(TAG, "...Connection established and data link opened...");
} 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, "...Creating 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 supported. Aborting.");
} else {
if (btAdapter.isEnabled()) {
Log.d(TAG, "...Bluetooth is enabled...");
} else {
//Prompt user to turn on Bluetooth
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
}
private void errorExit(String title, String message){
Toast msg = Toast.makeText(getBaseContext(),
title + " - " + message, Toast.LENGTH_SHORT);
msg.show();
finish();
}
private void sendData(String message) {
byte[] msgBuffer = message.getBytes();
Log.d(TAG, "...Sending data: " + message + "...");
try {
outStream.write(msgBuffer);
} catch (IOException e) {
String msg = "In onResume() and an exception occurred during write: " + e.getMessage();
msg = msg + ".\n\nCheck that the SPP UUID: " + MY_UUID.toString() + " exists on server.\n\n";
errorExit("Fatal Error", msg);
}
}
#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;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
And here's my Arduino script:
#include <SoftwareSerial.h>
#include <TimerOne.h>
#define Rx 2
#define Tx 3
#define seconds 4
char serialData; // Serial data memory
int counter1; // Overflow memory
int action; // Action trigger
int once = 0; // Run only once
SoftwareSerial Bluetooth(Rx, Tx);
void setup(){
pinMode(Tx, OUTPUT); // Configure Tx as OUTPUT (Transmitter)
pinMode(Rx, INPUT);
delay(1000);
Bluetooth.begin(9600);
Serial.begin(1200);
delay(1000);
Serial.print("Bluetooth ready");
Bluetooth.flush();
TimerOneSetup(); // Run the setup for Timer One
for(int i = 5; i <= 8; i++){ // Make pins 5, 6, 7 and 8 OUTPUT
pinMode(i, OUTPUT);
}
}
void interrupt1(){ // Timer One loop
counter1++; // Count the amount of seconds has passed
if (counter1 == seconds){ // Trigger the next action after a several amount of seconds (Default: 4 seconds)
action++;
counter1 = 0;
}
if (action > 3){ // Reset action trigger when after all actions were runned
action = 0;
}
}
void loop(){ // Endless loop
if (Serial.available()){ // Wait for data recieved from Local device
serialData = Serial.read(); // Put recieved data in memory
Serial.print("Data recieved from Local device: ");
Serial.println(serialData);
}
if (Bluetooth.available()){ // Wait for data recieved from Bluetooth device
serialData = Bluetooth.read(); // Put recieved data in memory
Serial.print("Data recieved from Bluetooth device: ");
Serial.print(serialData);
}
if (once == 0){ // This script will be run only once
serialData = 'e'; // Put switch on automatic on startup
once++; // Get into the next stage which may be run only once
}
switch(serialData){ // Perform action on state of the switch
case 'a':
fourtyLeds(); // Show the 40 Leds version of the Luma Mini
break;
case 'b':
thirtyLeds(); // Show the 30 Leds version of the Luma Mini
break;
case 'c':
twentyLeds(); // Show the 20 Leds version of the Luma Mini
break;
case 'd':
twelveLeds(); // Show the 12 Leds version of the Luma Mini
break;
case 'e':
while(serialData == 'e'){ // Keep changing different Led versions of the Luma Mini automatically
switch(action){
case 0: // Wait for the action trigger to hit the first action
fourtyLeds(); // Show the 40 Leds version of the Luma Mini
break;
case 1: // Wait for the action trigger to hit the second action
twelveLeds(); // Show the 12 Leds version of the Luma Mini
break;
case 2: // Wait for the action trigger to hit the third action
twentyLeds(); // Show the 20 Leds version of the Luma Mini
break;
case 4: // Wait for the action trigger to hit the fourth action
thirtyLeds(); // Show the 30 Leds version of the Luma Mini
break;}
if (Serial.read() == 'f'){ // Wait for data recieved from Local device
serialData = Serial.read(); // Put recieved data in memory
Serial.print("Data recieved from Local device: ");
Serial.println(serialData);
}
if (Bluetooth.read() == 'f'){ // Wait for data recieved from Bluetooth device
serialData = Bluetooth.read(); // Put recieved data in memory
Serial.print("Data recieved from Bluetooth device: ");
Serial.println(serialData);
}
break;
}
}
}
void BluetoothSetup(){
pinMode(Tx, OUTPUT); // Configure Tx as OUTPUT (Transmitter)
pinMode(Rx, INPUT); // Configure Rx as INPUT (Reciever)
Bluetooth.begin(9600); // Set Bluetooth baud rate to default baud rate 38400
Bluetooth.print("\r\n+STWMOD=0\r\n"); // Set the Bluetooth to work in slave mode
Bluetooth.print("\r\n+STNA=Luma Mini\r\n"); // Set Bluetooth name to Luma Mini
Bluetooth.print("\r\n+STOAUT=1\r\n"); // Permit paired device to connect
Bluetooth.print("\r\n+STAUTO=0\r\n"); // Auto-connection should be forbidden here
delay(2000);
Bluetooth.print("\r\n+INQ=1\r\n"); // Make this Bluetooth Slave inquirable
Serial.println("The slave Bluetooth is inquirable!");
delay(2000);
Bluetooth.flush();
}
void TimerOneSetup(){
Timer1.initialize(1000000); // Initialize Timer One for an overflow exactly every 1 second
Timer1.attachInterrupt(interrupt1); // Open the Timer One loop
}
void fourtyLeds(){ // Show the 40 Leds version of the Luma Mini
for(int i = 5; i <= 8; i++){
digitalWrite(i, LOW);
}
}
void thirtyLeds(){ // Show the 30 Leds version of the Luma Mini
digitalWrite(5, HIGH);
digitalWrite(6, LOW);
digitalWrite(7, LOW);
digitalWrite(8, LOW);
}
void twentyLeds(){ // Show the 20 Leds version of the Luma Mini
digitalWrite(5, HIGH);
digitalWrite(6, HIGH);
digitalWrite(7, LOW);
digitalWrite(8, HIGH);
}
void twelveLeds(){ // Show the 12 Leds version of the Luma Mini
for (int i = 5; i <= 8; i++){
digitalWrite(i, HIGH);
}
}
My question: How can I send CHAR data from an Android Device to my Arduino? And what to edit on my script?

I have not gone through your code. But looking at the question, I suggests to keep Arduino FW coding away till Android app is tested and developed to a certain level. The way forward could be:
Disconnect HC-06 from other hardware.
Make a loopback connection at HC-06 (i.e Connect TX & RX outputs of HC-06 together.
Then Test your Android application. If app is receiving same as transmitted, then your android app is ok, and you can move on perfecting Arduino FW. Else, the android app needs to be perfected.
You can have a look at a similar question HC-05 bluetooth module on Arduino + Debugging .

Here's the code I use, and it works fine for me.
On the Android side, I'm only including my bluetooth file, which should be easy to fit into your app. It's main advantage is that after your app start it by calling btConnect(), everything else is automatic. It finds and connects to your "HC-06" without further "human intervention". And if you turn off the "HC-06", Android will continue watching for the "HC-06" to come back online, and will auto-connect to it again.
The Arduino Sketch sends a signal once each second. If 10 seconds are missed, the Android assumes the connection has been lost and re-enters connect mode.
ANDROID BLUETOOTH JAVA FILE:
package com.exercise.androidanimbuttons;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.IntentFilter;
import android.widget.Toast;
import android.bluetooth.BluetoothSocket;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;
import java.util.Set;
import android.os.Handler;
public class BlueTooth extends vars {
private Set<BluetoothDevice> pairedDevices;
String address = null;
private ProgressDialog progress = null;
BluetoothAdapter myBluetooth = null;
BluetoothSocket btSocket = null;
InputStream mmInStream = null;
private Handler myHandler = new Handler();
byte[] buffer = new byte[25];
int readBytes;
files filesI = new files();
Handler btH = new Handler();
static final UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
private SingBroadcastReceiver mReceiver;
Runnable btSearch;
void stopDiscovery() {
if (myBluetooth.isDiscovering()){
myBluetooth.cancelDiscovery();
}
}
void findCurrentBT() {
if (!myBluetooth.isEnabled()){
Intent enableBT = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBT, 0xDEADBEEF);
}
if (myBluetooth.isDiscovering()){
myBluetooth.cancelDiscovery();
}
closeProgress();
progress = ProgressDialog.show(BlueTooth.this, "Searching for headband...",
"MAKE SURE THE HEADBAND IS TURNED ON.");
progress.setCanceledOnTouchOutside(true);
myBluetooth.startDiscovery();
mReceiver = new SingBroadcastReceiver();
IntentFilter ifilter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
this.registerReceiver(mReceiver, ifilter);
checkSearch();
}
private class SingBroadcastReceiver extends BroadcastReceiver {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
String derp = device.getName() + " - " + device.getAddress();
ta(derp);
Toast.makeText(context, derp, Toast.LENGTH_LONG);
if ((device.getName() != null) &&
(device.getName().indexOf("HC-06") == 0) &&
(device.getName().length() == 5))
{
myBluetooth.cancelDiscovery();
address = device.getAddress();
new ConnectBT().execute();
}
}
}
}
private Runnable readBT = new Runnable() {
public void run() {
int i;
int twoByte = 0;
short high = 0, low = 0;
try {
if (mmInStream.available() > 3) {
cnt = 0;
readBytes = mmInStream.read(buffer);
String S = "";
for (i = 0; i < 2; i++)
S += String.format("%03d", buffer[i] & 0xFF)+", ";
high = (short)(buffer[3] & 0xFF);
low = (short)(buffer[2] & 0xFF);
twoByte = ((high << 8) | low);
S += String.format("%03d", twoByte) + "\r\n";
filesI.writeALine("nights","data12.txt",S);
ta(S);
}
} catch (IOException e) {
ta("err:2 " + e.toString());
}
if (btSocket.isConnected())
myHandler.postDelayed(this, 100);
}
};
public void btConnect() {
Disconnect();
findCurrentBT();
}
public void btOn() {
turnOnLed();
}
public void btOff() { turnOffLed(); }
public void btDisconnect() { Disconnect(); }
private void Disconnect()
{
if (btSocket!=null)
{
try
{
btSocket.close();
}
catch (IOException e)
{ msg("Bluetooth Disconnect Error");}
}
}
private void turnOffLed()
{
if (btSocket!=null)
{
try
{
btSocket.getOutputStream().write("TF".toString().getBytes());
}
catch (IOException e)
{
msg("Error");
}
}
}
private void turnOnLed()
{
int len;
byte[] buffer = new byte[400];
if (btSocket!=null)
{
try
{
btSocket.getOutputStream().write("TO".toString().getBytes());
len = btSocket.getInputStream().available();
btSocket.getInputStream().read(buffer,0,len);
}
catch (IOException e)
{
msg("Error");
}
}
}
private void msg(String s)
{
Toast.makeText(getApplicationContext(),s,Toast.LENGTH_LONG).show();
}
void closeProgress() {
if (progress != null)
progress.dismiss();
}
private class ConnectBT extends AsyncTask<Void, Void, Void>
{
#Override
protected void onPreExecute()
{
closeProgress();
progress = ProgressDialog.show(BlueTooth.this, "Connecting to headband...",
"");
progress.setCanceledOnTouchOutside(true);
}
#Override
protected Void doInBackground(Void... devices)
{
try
{
if (btSocket == null || (!btSocket.isConnected()))
{
BluetoothDevice dispositivo = myBluetooth.getRemoteDevice(address);
btSocket = dispositivo.createInsecureRfcommSocketToServiceRecord(myUUID);
BluetoothAdapter.getDefaultAdapter().cancelDiscovery();
btSocket.connect();
}
}
catch (IOException e) { }
return null;
}
#Override
protected void onPostExecute(Void result)
{
super.onPostExecute(result);
if (!btSocket.isConnected())
{
msg("Connection Failed. Is the headband turned on?");
}
else
{
msg("Connected.");
try {
mmInStream = btSocket.getInputStream();
myHandler.postDelayed(readBT, 1000);
} catch (IOException e) {
ta("err:1 " + e.toString());
}
}
closeProgress();
}
}
int cnt = 0;
void checkSearch() {
if (btSearch != null)
return;
btSearch = new Runnable(){#Override public void run(){
if ((btSocket != null) && (btSocket.isConnected())) {
cnt--;
if (cnt < -10) {
cnt = 0;
btConnect();
}
} else if (myBluetooth.isDiscovering()) {
cnt++;
}
btH.postDelayed(this, 1000);
fa(cnt);
}};
btH.postDelayed(btSearch,1000);
}
}
MATCHING ARDUINO SKETCH:
byte mini [4];
int battery;
unsigned long mill = millis();
byte moveCnt = 1;
int minuteCnt = 0;
int lastMove = 0;
int moveA, moveB, moveC, LMoveA, LMoveB, LMoveC, totMove, eyes, LEyes, totEyes;
int moveUpA = 0;
int moveDnA = 1000;
int moveUpB = 0;
int moveDnB = 1000;
int moveUpC = 0;
int moveDnC = 1000;
#include <SoftwareSerial.h>
SoftwareSerial mySerial(3, 5); // RX, TX
void setup()
{
Serial .begin(9600);
mySerial.begin(9600);
}
void loop()
{
if (millis() > mill)
{
mill += 100;
minuteCnt++;
// *** EYES ***
eyes = analogRead(A6);
totEyes += abs(eyes-LEyes);
LEyes = eyes;
// *** MOVEMENT *** --KEEP-- moveA = max(0,analogRead(A1) >> 2);
moveA = analogRead(A0);
moveB = analogRead(A1);
moveC = analogRead(A2);
totMove += abs(moveA-LMoveA) + abs(moveB-LMoveB) + abs(moveC-LMoveC);
LMoveA = moveA; LMoveB = moveB; LMoveC = moveC;
// *** SEND SECOND ***
if (minuteCnt >= 10)
{
minuteCnt = 0;
// *** BATTERY ***
battery = analogRead(A5); // battery
mini[2] = (battery & 0xff); // battery low byte
mini[3] = ((battery >> 8) & 0xff); // battery high byte
// *** EYES ***
mini[0] = min(max(0,totEyes-10),255);
totEyes = 0;
// *** MOVEMENT ***
mini[1] = min(max(0,totMove-30),255);
totMove = 0;
Serial.print(mini[0]);
Serial.print(" ");
Serial.print(mini[1]);
Serial.print(" ");
Serial.print(mini[2]);
Serial.print(" ");
Serial.println(mini[3]);
mySerial.write(mini,4);
}
}
}

Multiple bluetooth socket connect/close operations reboot android phones

We are using android phones to communicate with sensors via bluetooth. The phone needs to connect the sensor periodically to collect physiological data and between two connections the sensors can be switched off automatically to save power.
Now the problem is: after around 500 times, the system reboots. We then wrote a small piece of test program to simulate the whole process. The small test program, too, crashes the android phone.
Can anybody please help me on this ? Thanks! Here is the small test program.
package zhb.test.MhubTestBtConnect;
import java.io.IOException;
import java.util.Date;
import java.util.UUID;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MhubTestBtConnect extends Activity implements OnClickListener{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btnStart = (Button) findViewById(R.id.btn_start_test);
btnStart.setOnClickListener(this);
Button btnStop = (Button) findViewById(R.id.btn_stop_test);
btnStop.setOnClickListener(this);
fBeginView = (TextView) findViewById(R.id.begin_time);
fBeginView.setText("off line");
fEndView = (TextView) findViewById(R.id.end_time);
fEndView.setText("off line");
fShowView = (TextView) findViewById(R.id.show_status);
fShowView.setText("off line");
fShowRunTimesView = (TextView) findViewById(R.id.show_times_status);
fShowRunTimesView.setText("off line");
fInputMac = (EditText) findViewById(R.id.edit_add_mac);
fInputMac.setText("00:19:5D:24:CB:A9");
fDisconnectGap = (EditText) findViewById(R.id.edit_disconnect_gap);
fDisconnectGap.setText("500");
fconnectGap = (EditText) findViewById(R.id.edit_connect_gap);
fconnectGap.setText("1000");
fRunning = false;
}
#Override
public void onClick(View v)
{
switch ( v.getId() )
{
case R.id.btn_start_test:
start();
break;
case R.id.btn_stop_test:
stop();
break;
default:
break;
}
}
private synchronized void start()
{
if ( fRunning == false )
{
fRunning = true;
fMac = fInputMac.getText().toString().toUpperCase();
fConnectRunnable = new ConnectRunnable();
fBeginView.setText(new Date().toLocaleString());
fConnectTimes = 0;
fRunOkTimes = 0;
new Thread(fConnectRunnable).start();
}
}
private synchronized void stop()
{
if ( fRunning == true )
{
fRunning = false;
fConnectRunnable.cancel();
try
{
Thread.sleep(500);
}
catch (InterruptedException exception)
{
exception.printStackTrace();
}
fEndView.setText(new Date().toLocaleString());
}
}
private void connect()
{
Log.d(TAG,"---------- run "+fConnectTimes++ +" times");
String UUID_STRING = "00001101-0000-1000-8000-00805F9B34FB";
// may throws exception
UUID uuid = UUID.fromString(UUID_STRING);
// get adapter
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
// get remote device
BluetoothDevice btDevice = adapter.getRemoteDevice(fMac);
if ( btDevice == null )
{
Log.e(TAG,"can't get remote device from given MAC : " + fMac);
return;
}
int runResult = 0;
// may throws exception
fBtSocket = null;
try
{
fBtSocket = btDevice.createRfcommSocketToServiceRecord(uuid);
if ( adapter.isDiscovering() == true )
{
adapter.cancelDiscovery();
Log.d(TAG,"cancel discover");
}
fBtSocket.connect();
runResult = 1;
Log.d(TAG,"connect socket OK");
Log.d(TAG,"---------- run OK "+fRunOkTimes++ +" times");
}
catch (IOException exception)
{
//adapter.cancelDiscovery();
Log.d(TAG,"connect socket error",exception);
if ( fBtSocket != null )
{
try
{
fBtSocket.close();
}
catch (IOException exception1)
{
Log.d(TAG,"close socket error",exception1);
}
}
else
{
Log.d(TAG,"create socket NULL");
}
btDevice = null;
//update ui
Message msgRun = new Message();
msgRun.what = R.id.show_status;
msgRun.arg1 = SV_START_RUN;
msgRun.arg2 = runResult;
fMessHandler.sendMessage(msgRun);
}
//Note: You should always ensure that the device is not performing device discovery when you call connect().
//If discovery is in progress, then the connection attempt will be significantly slowed and is more likely to fail.
//adapter.cancelDiscovery();
}
private void close()
{
//update ui
Message msgShut = new Message();
msgShut.what = R.id.show_status;
msgShut.arg1 = SV_SHUT_DOWN;
fMessHandler.sendMessage(msgShut);
if ( fBtSocket != null )
{
Log.d(TAG,"close socket");
try
{
fBtSocket.close();
}
catch (IOException exception1)
{
Log.d(TAG,"close socket error",exception1);
}
fBtSocket = null;
}
}
private Handler fMessHandler = new Handler()
{
public void handleMessage(android.os.Message msg)
{
switch ( msg.what )
{
case R.id.show_status:
if ( msg.arg1 == SV_START_RUN )
{
if ( msg.arg2 == 1)
fShowView.setText("run OK");
else
fShowView.setText("run Failed");
fShowRunTimesView.setText("run "+fConnectTimes+", OK "+fRunOkTimes);
}
else if ( msg.arg1 == SV_SHUT_DOWN )
fShowView.setText("shut down ...");
break;
default:
break;
}
};
};
private long fConnectTimes;
private long fRunOkTimes;
private static final String TAG = "..MhubTestBtConnect";
private BluetoothSocket fBtSocket;
private ConnectRunnable fConnectRunnable;
private String fMac;
private boolean fRunning;
private TextView fBeginView;
private TextView fEndView;
private TextView fShowView;
private TextView fShowRunTimesView;
private EditText fInputMac;
private EditText fDisconnectGap;
private EditText fconnectGap;
private static final int SV_START_RUN = 1;
private static final int SV_SHUT_DOWN = 2;
private class ConnectRunnable implements Runnable
{
public ConnectRunnable()
{
fCancelled = false;
}
#Override
public void run()
{
if (Looper.myLooper() == null) {
Looper.prepare();
}
long afterConnectSleep = 500;
long afterCloseSleep = 1000;
try
{
afterCloseSleep = Integer.parseInt(fconnectGap.getText().toString());
afterConnectSleep = Integer.parseInt(fDisconnectGap.getText().toString());
}
catch(Exception exception)
{
afterConnectSleep = 500;
afterCloseSleep = 1000;
}
while ( fCancelled == false )
{
connect();
try
{
Thread.sleep(afterConnectSleep);
}
catch (InterruptedException exception)
{
exception.printStackTrace();
}
close();
try
{
Thread.sleep(afterCloseSleep);
}
catch (InterruptedException exception)
{
exception.printStackTrace();
}
}
}
public void cancel()
{
fCancelled = true;
}
private boolean fCancelled;
}
}

This is a bug I reported a while back regarding failed bluetooth connects (512 to be exact) and a memory leak leading to "referencetable overflow. I'll dig up the link when I'm back at my PC =)
Link: http://code.google.com/p/android/issues/detail?id=8676
Solution: avoid failed bluetooth connects by performing a Bluetooth discovery first to see if the device is in range. If so, cancel discovery and connect to it.