I'm currently trying to fix a problem I encountered with my Android app which require a Bluetooth connection. For a moment everything seem to work right, But i noticed something strange when the slave Bluetooth device, I want to connect with, is not powered on. Here is my code :
private void connectDevice() {
mBluetoothAdapter.cancelDiscovery();
BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
try {
btSocket = createBluetoothSocket(device);
} catch (IOException e) {
errorExit("Fatal Error", "Socket create failed: " + e.getMessage() + ".");
}
//Try to 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", "Unable to close socket during connection failure" + e2.getMessage() + ".");
}
}
//Create a data stream so we can talk to server.
Log.d(TAG, "...Create Socket...");
mConnectedThread = new ConnectedThread(btSocket);
mConnectedThread.start();
mActionBar.setSubtitle("Connected");
return;
}
And here is where I call this method :
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch(requestCode){
case REQUEST_ENABLE_BT:
if (resultCode == RESULT_OK) {
Toast.makeText(this, R.string.bt_enabled, Toast.LENGTH_SHORT).show();
setupCom();
break;
}
else {
// User did not enable Bluetooth or an error occurred
if(D) Log.d(TAG, "BT not enabled");
Toast.makeText(this, R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show();
finish();
break;
}
case REQUEST_CONNECT_DEVICE:
if (resultCode == RESULT_OK){
retrieveAddresse(data);
connectDevice();
}
break;
}
return;
}
My problem is that, when I'm not in range or the device I want to connect to is not powered on, the connectDevice() method seem to execute all the code even if it's not possible to connect because Android OS don't want to be blocked by the connection process. I noticed this problem because mActionBar.setSubtitle("Connected"); get executed and because when I try to reconnect when I'm in range or the slave bluetooth module is ON. I can't connect to it unless I relaunch my application.
Put these lines :
mConnectedThread = new ConnectedThread(btSocket);
mConnectedThread.start();
mActionBar.setSubtitle("Connecté");
inside the first try. In this way they will be executed only if the devices establish a connection. As actually they are outside try/catch, they will always executed, even without connection.
Related
I'm trying to set up a system where an android app connects to Arduino via Bluetooth and tells it to either turn on or off its LED. I've looked through a lot of pages and source code and saw many people did it as I did but somehow my code isn't working and I cannot determine why.
Here's the entirety of my Arduino code, really simple and short.
#include <SoftwareSerial.h>
SoftwareSerial Blue(0,1); // rx tx
int LED = 13; // Led connected
char data;
char state = 0;
void setup()
{
pinMode(LED, OUTPUT);
digitalWrite(LED, LOW);
Serial.begin(9600);
Blue.begin(9600);
}
void loop()
{
while(Blue.available()==0);
if(Blue.available()>0){ // read from android via bluetooth
data = Blue.read();
Serial.println(data);
}
if (data == '1') // If data is 1, turn ON the LED
{
digitalWrite(LED,HIGH);
Serial.println("LED ON ");
}
if( data == '2') // if data is 2, turn OFF the LED
{
digitalWrite(LED,LOW);
Serial.println("LED OFF");
}
}
And here's a snippet of my android code that sends data to Arduino to control LED
switchLight.setOnClickListener(new View.OnClickListener() { // button that will switch LED on and off
#Override
public void onClick(View v) {
Log.i("[BLUETOOTH]", "Attempting to send data");
if (mmSocket.isConnected() && btt != null) { //if we have connection to the bluetoothmodule
if (!lightflag) {
try{
mmSocket.getOutputStream().write("1".toString().getBytes());
showToast("on");
}catch (IOException e) {
showToast("Error");
// TODO Auto-generated catch block
e.printStackTrace();
}
//btt.write(sendtxt.getBytes());
lightflag = true;
} else {
try{
mmSocket.getOutputStream().write("2".toString().getBytes());
showToast("off");
}catch (IOException e) {
showToast("Error");
// TODO Auto-generated catch block
e.printStackTrace();
}
//btt.write(sendtxt.getBytes());
lightflag = false;
}
}
else {
Toast.makeText(MainActivity.this, "Something went wrong", Toast.LENGTH_LONG).show();
}
}
});
This is the part of the code that connects to Arduino Bluetooth module. Again, fairly simple stuff and its only purpose are to connect to the module.
BluetoothAdapter bta; //bluetooth stuff
BluetoothSocket mmSocket; //bluetooth stuff
BluetoothDevice mmDevice; //bluetooth stuff
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.i("[BLUETOOTH]", "Creating listeners");
final TextView response = findViewById(R.id.response);
Button switchLight = findViewById(R.id.switchlight);
Button connectBT = findViewById(R.id.connectBT);
connectBT.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
BluetoothSocket tmp = null;
mmDevice = bta.getRemoteDevice(MODULE_MAC);
Log.i("[BLUETOOTH]", "Attempting to send data");
try {
tmp = mmDevice.createRfcommSocketToServiceRecord(MY_UUID);
mmSocket = tmp;
mmSocket.connect();
Log.i("[BLUETOOTH]","Connected to: "+mmDevice.getName());
showToast("Connected to: " + mmDevice.getName());
}catch(IOException e){
try {mmSocket.close();
}catch(IOException c){return;}
}
}
});
When I connect my android to the Arduino and track the serial monitor on Arduino IDE, instead of reading either 1 or 2, it reads something that looks like this:
This is produced using the Serial. println function in my Arduino code and I'm pretty sure it should display 1 or 2 but as you can see it does not. I've tried multiple workarounds like declaring it as int or char etc. If you can pinpoint any issue I'd much appreciate it.
I am facing this error while disabling Bluetooth. Googled it but did not find solution. Here is my broadcast receiver which invokes when bluetooth state is changed.
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
Log.e(LOG_TAG, "Broadcast receiver - onReceive");
if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
h.removeCallbacks(runnable);
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);
switch (state) {
case BluetoothAdapter.STATE_OFF:
Log.i(LOG_TAG, "***** BLE-Bluetooth is disabled");
Toast.makeText(getApplicationContext(), "Bluetooth is disabled", Toast.LENGTH_LONG).show();
Log.i(TAG, "***** mBeaconScanner "+ mBeaconScanner);
if(null != mBeaconScanner)
mBeaconScanner.scanLeDevice(false);
break;
case BluetoothAdapter.STATE_ON:
Log.i(LOG_TAG, "***** BLE-Bluetooth is enabled");
Toast.makeText(getApplicationContext(), "Bluetooth is enabled", Toast.LENGTH_LONG).show();
if(null != mBeaconScanner)
mBeaconScanner.scanLeDevice(true);
break;
}
}
}
};
In the above code I am trying to stop ble scanning while disabling the Bluetooth. In the above code method "mBeaconScanner.scanLeDevice(false);" redirects to :
Log.i(TAG, "***** Stopping BLE Scan for Android version " + Build.VERSION.SDK_INT);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
if (bluetoothLeScanner != null)
{
bluetoothLeScanner.stopScan(mScanCallback);
}
} else {
mBluetoothAdapter.stopLeScan(mLeScanCallback);
}
In the above snippet I am getting Exception when calling bluetoothLeScanner.stopScan(mScanCallback) method.
NOTE: this issue is not reproducible in all the devices but nexus and its not very frequently reproducible as well for me.
Please suggest me if there is any solution for this.. Thanks in advance
The only solution I can suggest here is comment this code:-
//mBeaconScanner.scanLeDevice(false);
The way BLE scan works is pretty complicated at the radio level. There are tons of factors (like power, efficiency etc..) that are taken into consideration while arriving at the right scan window sleep time etc..
For you in this particular case when the BT adapter itself is turned OFF, trying to stop scan is an invalid operation as far as the radio is concerned. Am glad that Android FW throws this exception !! Just get rid of this code and may be do some internal app specific state transition (if you have to) or else just log and be done in case BluetoothAdapter.STATE_OFF:
I have a part of code in which I firstly setText, then make a Toast and after that I'm trying to connect via Bluetooth. The problem is that my setText and Toasts appear only after connection has been made.
I tried to put Log.i instead of Toasts and they were shown simultaneously.
Can somebody explain me why and how to make Toasts simultaneously?
Code:
........
else if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action)) {
tvDevices.setText("");
Toast.makeText(getApplicationContext(), "Lost connection!", Toast.LENGTH_SHORT).show();
connect(btDevice, ConstantsVariables.reconnectionAttempts);
}
public void connect(BluetoothDevice bt, int attempts){
Toast.makeText(getApplicationContext(), "Trying to connect...", Toast.LENGTH_SHORT).show();
if(attempts > 0){
for(int i = 1; i <= ConstantsVariables.reconnectionAttempts; i++){
ConnectThread thread = new ConnectThread(bt);
boolean connectVar = thread.connect();
if(connectVar){
break;
}
}
}
}
.......
public boolean connect() {
BA.cancelDiscovery();
try {
mSocket.connect();
} catch (IOException e) {
Log.d("CONNECTTHREAD","Could not connect: " + e.toString());
try {
mSocket.close();
} catch (IOException exception){}
return false;
}
return true;
}
It is possible that you're blocking the UI Thread while connection is being attempted. Try to move the connection code to a background thread, or an AsyncTask, and handle the UI Changes in the AsyncTask's callbacks.
Edit: Also the context getApplicationContext() passed to Toast is ambiguous. Are you in an activity? In that case it should simply point to the Activity's context i.e. this and not the Application's context
I have barcode scanner who should work with my app. It is supposed to run in the background and my app is responding to input coming from the scanner in its own way. However it should not be used as a hardware keyboard and its input not directed to the firstresponder (no text entries i.e.). Currently i'm stuck with it although i know i have done a solution like described before (couple years ago for a company).
The first part of the question is now how to prevent the bluetooth device from being attached as a hardware keyboard? Can i control this behaviour or is it maybe some mode or setting that the bluetooth device must support (if yes is there name for it to check in the specifications)?
I guess if the device is not attached as a bluetooth keyboard i could establish a connection and listen to the bluetooth socket input stream for available bytes and collect them. Currently i cannot establish a connection because
UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
socket = device.createRfcommSocketToServiceRecord(uuid);
socket.connect();
throws an java.io.IOException with message read failed, socket might closed or timeout, read ret: -1. Any ideas why i cannot connect to the socket, although the device is currently paired to my device?
EDIT:
Because it was asked, the complete connection source code
private void initBluetooth() {
BTAdapter = BluetoothAdapter.getDefaultAdapter();
if (BTAdapter == null) {
Log.e(getClass().getName(), "no BT Adapter");
return;
}
if (!BTAdapter.isEnabled()) {
Intent enableBT = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBT, REQUEST_BLUETOOTH);
return;
}
listDevices();
}
private void listDevices() {
Set<BluetoothDevice> pairedDevices = BTAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
for (BluetoothDevice device : pairedDevices) {
Log.d(getClass().getName(), String.format("Device found %s", device.getName()));
if(device.getName().indexOf("Barcode") > 0) {
mmDevice = device;
try {
openBT();
} catch(IOException e) {
Log.e(getClass().getName(), "Failed", e);
}
break;
}
}
}
}
void openBT() throws IOException
{
UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);
//now make the socket connection in separate thread
Thread connectionThread = new Thread(new Runnable() {
#Override
public void run() {
// Always cancel discovery because it will slow down a connection
BTAdapter.cancelDiscovery();
// Make a connection to the BluetoothSocket
try {
// This is a blocking call and will only return on a
// successful connection or an exception
mmSocket.connect();
} catch (IOException e) {
//connection to device failed so close the socket
e.printStackTrace();
try {
mmSocket.close();
} catch (IOException e2) {
e2.printStackTrace();
}
}
}
});
connectionThread.start();
mmInputStream = mmSocket.getInputStream();
}
I've been trying to create a function in my app that consist in a bluetooth RFID scanner, it's paired to my device and I have it working and all.
I can receive the text and log it in the console, when I compile the activity, everything goes fine, the stick reads the code, and then appends the text into an EditText, but if I go back and enter the activity again, I can see the code in the log, but the text doesn't go to the Edittext.
I tried a lot of different approaches, but nothing seems to work :/
here's the code I have:
/**
* Called when the activity is first created.
*/
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.bluetooth);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set<BluetoothDevice> bondedSet = mBluetoothAdapter.getBondedDevices();
if (mBluetoothAdapter == null) {
Toast.makeText(this, "Bluetooth is not available.", Toast.LENGTH_LONG).show();
}
if (!mBluetoothAdapter.isEnabled()) {
Toast.makeText(this, "Please enable your BT and re-run this program.", Toast.LENGTH_LONG).show();
finish();
}
if (mBluetoothAdapter.isEnabled()) {
if(bondedSet.size() == 1){
for(BluetoothDevice device : bondedSet){
address = device.getAddress();
Log.d("bt:", address);
}
}
}
String address = "00:A0:96:2A:0A:1B";
out = (EditText) findViewById(R.id.output);
BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
Log.d(TAG, device.getName() + " connected");
myConnection = new ConnectThread(device);
myConnection.start();
}
private class ConnectThread extends Thread {
private final BluetoothSocket mySocket;
Message msg;
public ConnectThread(BluetoothDevice device) {
BluetoothSocket tmp = null;
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
Log.d(TAG, "CONNECTION IN THREAD DIDNT WORK");
}
mySocket = tmp;
}
Handler uiThreadHandler = new Handler() {
public void handleMessage(Message msg) {
out = (EditText) findViewById(R.id.output);
Object o = msg.obj;
out.append(o.toString().trim());
Log.d("handler", o.toString());
}
};
public void run() {
out = (EditText) findViewById(R.id.output);
Log.d(TAG, "STARTING TO CONNECT THE SOCKET");
setName("My Connection Thread");
InputStream inStream = null;
boolean run = false;
mBluetoothAdapter.cancelDiscovery();
try {
mySocket.connect();
run = true;
} catch (IOException e) {
Log.d(TAG, this.getName() + ": CONN DIDNT WORK, Try closing socket");
try {
mySocket.close();
Log.d(TAG, this.getName() + ": CLOSED SOCKET");
} catch (IOException e1) {
Log.d(TAG, this.getName() + ": COULD CLOSE SOCKET", e1);
this.destroy();
}
run = false;
}
synchronized (BluetoothActivity.this) {
myConnection = null;
}
byte[] buffer = new byte[1024];
int bytes;
// handle Connection
try {
inStream = mySocket.getInputStream();
while (run) {
try {
bytes = inStream.read(buffer);
readMessage = new String(buffer, 0, bytes);
msg = uiThreadHandler.obtainMessage();
msg.obj = readMessage;
uiThreadHandler.sendMessage(msg);
Log.d(TAG, "Received: " + readMessage);
} catch (IOException e3) {
Log.d(TAG, "disconnected");
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
My guess is that this has something to do with the Thread itself. When you start your Activity for the first time, you also call .start() on the Thread, that would work fine.
The problem is when you leave your Activity and open it up again. In that case, one of onStop() or onPause() is called (depending on situation), and onRestart() or onResume() will be called afterwards respectively.
The trick comes now: Meanwhile all that process, your Thread is still running. As you show your code, it has not been stopped/paused, and keeps running all the time. So basically my tip is that there's something you do within your onCreate() method of your Activity that should also be done in your onPause() and onStop() events, and my another tip it's somewhere within your ConnectThread(BluetoothDevice device) method.
To know how to procceed, I'd firstly define both onStop() and onPause() methods within your Activity and see which is fired, log every attribute to see its value/state, and that way you'll be able to debug what is failing.
There's a diagram of the Activity lifecycle.
Problem was solved, the code works, and the TextView get the inputstream, the problem was when i left the activity, the thread continued to work, so far, no problem at all, after TONS of hours spent on this, i turn the TextView a static var and it worked :)
If anyone reads this, i hope it helps.