Bluetooth data transfer between two Android devices
Solution 1
Check out the BluetoothChat example that Google provides in the SDK. It'll show you how to implement basic sending of text over bluetooth.
Solution 2
You can also try the tutorial example here
Simpsons
Updated on March 20, 2020Comments
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Simpsons about 4 years
I have been following this Android guide for Bluetooth communication
To explain exactly what I want to do, when the two devices are paired, two different activities open up on each device (server and client) where on the server activity I have different buttons, and on the client activity there is just a textview. I want to be able to press a button on the server device and display it on the client.
I have managed to establish a connection between the two devices, but now I want to send data which I have not been able to do.
They give this code for data transfer:
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) { } } }
But this line generates an error
// Send the obtained bytes to the UI activity mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();
And is not explained in the guide. I don't know what the mHandler is or does.
Apart from the error, I don't even really understand where to put this code. Should it be in the second activities (server and client) that I open or in the main? If in the Server activity, should it be in the onClick method for all the buttons with a different byte code to send for each button? And in this code, how do we distinguish who is sending and who is receiving?
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ban-geoengineering over 5 yearsThe link in this answer is very old. There is an updated official example of the BluetoothChat app here: github.com/googlesamples/android-BluetoothChat
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ban-geoengineering over 5 yearsTo link in the question doesn't work, but you can find the (current) official BluetoothChat example app here: github.com/googlesamples/android-BluetoothChat