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Help with serial read-in
Hi I have the following code which reads in data from a bluetooth transmitter, however the program is crashing upon read-in. The bluetooth connects to the device just fine, as indicated by the indicator LED on the transmitter. However during the read-in:
void beginListenForData()
is where the exception happens. Specifically, it is at the line
readBuffer[readBufferPosition++] = b;
however I don't know why it is crashing. My transmitter is sending 1 byte (0x02) at 9600 baud every 1 sec for testing purposes.
package com.example.bluetoothtest2; 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.os.Handler; import android.util.Log; import android.view.View; import android.widget.TextView; import android.widget.EditText; import android.widget.Button; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.Set; import java.util.UUID; public class MainActivity extends Activity { TextView myLabel; EditText myTextbox; BluetoothAdapter mBluetoothAdapter; BluetoothSocket mmSocket; BluetoothDevice mmDevice; OutputStream mmOutputStream; InputStream mmInputStream; Thread workerThread; byte[] readBuffer; int readBufferPosition; int counter; volatile boolean stopWorker; String tag = "debugging"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button openButton = (Button)findViewById(R.id.open); Button sendButton = (Button)findViewById(R.id.send); Button closeButton = (Button)findViewById(R.id.close); myLabel = (TextView)findViewById(R.id.label); myTextbox = (EditText)findViewById(R.id.entry); //Open Button openButton.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { try { findBT(); openBT(); } catch (IOException ex) { } } }); //Send Button sendButton.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { try { sendData(); } catch (IOException ex) { } } }); //Close button closeButton.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { try { closeBT(); } catch (IOException ex) { } } }); } void findBT() { mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); if(mBluetoothAdapter == null) { myLabel.setText("No bluetooth adapter available"); } if(!mBluetoothAdapter.isEnabled()) { Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBluetooth, 0); } Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices(); if(pairedDevices.size() > 0) { for(BluetoothDevice device : pairedDevices) { if(device.getName().equals("RN42-403A")) { mmDevice = device; break; } } } myLabel.setText("Bluetooth Device Found"); } void openBT() throws IOException { UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); //Standard SerialPortService ID mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid); mmSocket.connect(); mmOutputStream = mmSocket.getOutputStream(); mmInputStream = mmSocket.getInputStream(); beginListenForData(); //myLabel.setText("Bluetooth Opened"); } void beginListenForData() { final Handler handler = new Handler(); final byte delimiter = 10; //This is the ASCII code for a newline character stopWorker = false; readBufferPosition = 0; readBuffer = new byte[1]; workerThread = new Thread(new Runnable() { public void run() { while(!Thread.currentThread().isInterrupted() && !stopWorker) { try { int bytesAvailable = mmInputStream.available(); if(bytesAvailable > 0) { byte[] packetBytes = new byte[bytesAvailable]; mmInputStream.read(packetBytes); for(int i=0;i<bytesAvailable;i++) { Log.i(tag, "in for loop"); System.out.println(i); byte b = packetBytes[i]; System.out.println(b); Log.i(tag, "after b"); if(b == delimiter) //THIS IS THE PROBLEM, NEVER ENTERS THis IF STATEMENT { Log.i(tag, "reach delim"); byte[] encodedBytes = new byte[readBufferPosition]; System.arraycopy(readBuffer, 0, encodedBytes, 0, encodedBytes.length); final String data = new String(encodedBytes, "US-ASCII"); readBufferPosition = 0; Log.i(tag, "Read buff 0"); handler.post(new Runnable() { public void run() { myLabel.setText(data); Log.i(tag, "set text"); } }); } else { System.out.println(b); readBuffer[readBufferPosition++] = b; Log.i(tag, "Read buff"); } } } } catch (IOException ex) { stopWorker = true; } } } }); workerThread.start(); } void sendData() throws IOException { String msg = myTextbox.getText().toString(); msg += "\n"; mmOutputStream.write(msg.getBytes()); myLabel.setText("Data Sent"); } void closeBT() throws IOException { stopWorker = true; mmOutputStream.close(); mmInputStream.close(); mmSocket.close(); myLabel.setText("Bluetooth Closed"); } }
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