I used this code to read the reply of a Bluetooth not LE device.
The solution is a Xamarin Forms project and the code is in the DependencyService.
using Android.Bluetooth;
....
public byte[] GetCommand()
{
byte[] rbuffer = new byte[200];
try
{
// Read data from the device
while (!_socket.InputStream.CanRead || !_socket.InputStream.IsDataAvailable())
{
}
int readByte = _socket.InputStream.Read(rbuffer, 0, rbuffer.Length);
}
catch (Java.IO.IOException e)
{
}
return rbuffer;
}
How is it possible to solve it?
I would use the following code instead:
//create new class for connect thread
private class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
//creation of the connect thread
public ConnectedThread(BluetoothSocket socket) {
InputStream tmpIn = null;
OutputStream tmpOut = null;
try {
//Create I/O streams for connection
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[256];
int bytes;
// Keep looping to listen for received messages
while (true) {
try {
bytes = mmInStream.read(buffer); //read bytes from input buffer
String readMessage = new String(buffer, 0, bytes);
// Send the obtained bytes to the UI Activity via handler
bluetoothIn.obtainMessage(handlerState, bytes, -1, readMessage).sendToTarget();
} catch (IOException e) {
break;
}
}
}
//write method
public void write(String input) {
byte[] msgBuffer = input.getBytes(); //converts entered String into bytes
try {
mmOutStream.write(msgBuffer); //write bytes over BT connection via outstream
} catch (IOException e) {
//if you cannot write, close the application
Toast.makeText(getBaseContext(), "Connection Failure", Toast.LENGTH_LONG).show();
finish();
}
}
}
This is working for me to get bluetooth information from an Arduino! :)
Related
Im using one app to send data to the elm327 through bluetooth and I'm trying the AT Z command but everything I get back from the OBD2 is AT Z too, my code is missing something or its supposed to answer like that ? I expected the AT Z to return elm327 text (tested with playstore apps and thats what I got)
// runs during a connection with a remote device
private class ReadWriteThread extends Thread {
private final BluetoothSocket bluetoothSocket;
private final InputStream inputStream;
private final OutputStream outputStream;
public ReadWriteThread(BluetoothSocket socket) {
this.bluetoothSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
}
inputStream = tmpIn;
outputStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[1024];
int bytes;
// Keep listening to the InputStream
while (true) {
try {
// Read from the InputStream
bytes = inputStream.read(buffer);
// Send the obtained bytes to the UI Activity
handler.obtainMessage(MainActivity.MESSAGE_READ, bytes, -1,
buffer).sendToTarget();
} catch (IOException e) {
connectionLost();
// Start the service over to restart listening mode
ChatController.this.start();
break;
}
}
}
// write to OutputStream
public void write(byte[] buffer) {
try {
outputStream.write(buffer);
handler.obtainMessage(MainActivity.MESSAGE_WRITE, -1, -1,
buffer).sendToTarget();
} catch (IOException e) {
}
}
public void cancel() {
try {
bluetoothSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Perhaps you're not reading enough – make sure you concatenate all fragments you read until you receive the actual prompt \r>.
ELM327 usually starts out in echo mode, where it echos every command you are giving to it, that may explain why you're reading it back. Use ATE0 to turn off this behavior.
In general, https://www.sparkfun.com/datasheets/Widgets/ELM327_AT_Commands.pdf explains all that.
I'am a newbie to android Bluetooth and I want to read and store the Bluetooth message in external android app(mine) using internal storage or sqlite. I have tried the android bluetooth-chat sample from GitHub but I don't know how to implement my idea.
Any help would be helpful and thanks
Exchange of bluetooth messages is covered in the android.bluetooth section of the api.
http://developer.android.com/guide/topics/connectivity/bluetooth.html#ManagingAConnection
Here is a basic example of managing a connection and sending/receiving messages:
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI activity
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
} catch (IOException e) {
break;
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
mmOutStream.write(bytes);
} catch (IOException e) { }
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
I'm trying to receive data from multiple device in same time, i'm using createInsecureRfcommSocketToServiceRecord() and the SPP UUID 00001101-0000-1000-8000-00805F9B34FB to connect to non-android devices.
So i'm running 3 instance of ConnectedThread, i'm able to write to all device, but i can't receive from 2 device at same time.
Example : i'm connecting to 2 Pc using HyperTerminal, if i send a txt file on both at the same time, i will receive only one on my android device, the other one is ignored.
I'm looking this library : http://arissa34.github.io/Android-Multi-Bluetooth-Library/ seems i have to run a server on my android phone.
How can I achieve this?
Best regards.
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI activity
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
} catch (IOException e) {
break;
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
mmOutStream.write(bytes);
} catch (IOException e) { }
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
I am new to Object Input Streams and Object Output Streams but I have to use them to send a string over Bluetooth. Whenever I try to make the connection both phones freeze and then crash. I used the debugger and the last line it stopped at before the program froze is: tmpIn = new ObjectInputStream(socket.getInputStream());
Here is my connection thread:
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final ObjectInputStream mmInStream;
private final ObjectOutputStream mmOutStream;
private FileOutputStream mmFileOut = null;
public ConnectedThread(BluetoothSocket socket, String socketType) {
Log.d(TAG, "create ConnectedThread: " + socketType);
mmSocket = socket;
ObjectInputStream tmpIn = null;
ObjectOutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
//input stream
//mmFileIn = new FileInputStream("t.tmp");
tmpIn = new ObjectInputStream(socket.getInputStream());
//output stream
mmFileOut = new FileOutputStream("t.tmp");
tmpOut.flush();
tmpOut = new ObjectOutputStream(mmFileOut);
tmpOut.writeObject(socket.getOutputStream());
}catch (FileNotFoundException fnfe){
System.out.println("FileOutPutStream: "+ fnfe);
}catch (IOException ie){
System.out.print("ObjectOutputStream: " + ie);
}catch (Exception e){
System.out.print(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 {
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI Activity
mHandler.obtainMessage(Constants.MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
} catch (IOException e) {
Log.e(TAG, "disconnected", e);
connectionLost();
// Start the service over to restart listening mode
BluetoothChatService.this.start();
break;
}
}
}
/**
* 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(Constants.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);
}
}
}
I read somewhere it may have to do with using .flush() on my Object Output Stream am I using that correctly?
The code in the constructor runs on the UI thread. Move it to run().
I need to show data to a TextView from a serial Bluetooth.
But when i connect my application with the serial device, it did connected but suddenly went forced closed. The logcat shows nothing so I don't know what's wrong.
This is the code when application listens the inputstream while connected:
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
int bytes;
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
//mEmulatorView.write(buffer, bytes);
mTextView.append(new String(buffer));
// Send the obtained bytes to the UI Activity
//mHandler.obtainMessage(BlueTerm.MESSAGE_READ, bytes, -1, buffer).sendToTarget();
String a = buffer.toString();
mTextView.setText(a);
a = "";
} catch (IOException e) {
Log.e(TAG, "disconnected", e);
connectionLost();
break;
}
}
}
and TextView mTextView = (TextView) findViewById(R.id.dataTerm);
and on the layout:
<TextView
android:id="#+id/dataTerm"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
So does anyone know what went wrong?
Any answers are so helpful, thanks..
The code that finally work
On the main file, in my case named FinalSetting:
On the Activity method, declare:
//Layout View
private static TextView mTextView;
On the onCreate(Bundle savedInstanceState) method declare the textview:
mTextView = (TextView) findViewById(R.id.dataTerm);
On the Handler method:
case MESSAGE_READ:
byte[] readBuf = (byte[]) msg.obj;
//mEmulatorView.write(readBuf, msg.arg1);
// construct a string from the valid bytes in the buffer
String readMessage = new String(readBuf, 0, msg.arg1);
//mConversationArrayAdapter.add(mConnectedDeviceName+": " + readMessage);
mTextView.setText(readMessage);
break;
On the BluetoothService.java file:
Let's just straight to the method
//This thread runs during a connection with a remote device.
//It handles all incoming and outgoing transmissions.
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];
//final byte[] buffer = new byte[1024];
int bytes;
// Keep listening to the InputStream while connected
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
//Send the obtained bytes to the UI Activity
mHandler.obtainMessage(FinalSetting.MESSAGE_READ, bytes, -1, buffer).sendToTarget();
} catch (IOException e) {
Log.e(TAG, "disconnected", e);
connectionLost();
break;
}
}
}
/**
* 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(FinalSetting.MESSAGE_WRITE, buffer.length, -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);
}
}
}
After you connect to the serial Bluetooth device, the data will show up on the TextView.
Hope this help :D
Seems like you are trying to modify mTextView in a non-UI thread which is illegal and might be the reason for FC (if not any other issue). However you can achieve this as below:
Change this:
mTextView.append(new String(buffer));
To this:
mTextView.post(new Runnable() {
#Override
public void run() {
mTextView.append(new String(buffer));
}
});