Read data from bluetooth device

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Read data from bluetooth device

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#1 by (4 votes)

5

I am developing an Android application and I implemented a bluetooth bar code reader, the problem is that I could not get to read what the device delivers. In my class I can see and get the devices associated with my phone but I can not read what it delivers.

I leave the class I occupy and if someone can help me with this, I would be grateful.

import android.os.Bundle;
    import android.app.Activity;
    import android.bluetooth.BluetoothAdapter;
    import android.bluetooth.BluetoothDevice;
    import android.bluetooth.BluetoothSocket;
    import android.content.BroadcastReceiver;
    import android.content.Context;

    import java.io.BufferedReader;
    import java.io.Closeable;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.util.Set;
    import java.util.UUID;

    import android.content.Intent;
    import android.content.IntentFilter;
    import android.util.Log;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.ArrayAdapter;
    import android.widget.Button;
    import android.widget.ListView;
    import android.widget.TextView;
    import android.widget.Toast;

    public class Test extends Activity {

       private static final int REQUEST_ENABLE_BT = 1;
       private Button onBtn;
       private Button offBtn;
       private Button listBtn;
       private Button findBtn;
       private TextView text;
       private BluetoothAdapter myBluetoothAdapter;
       private Set<BluetoothDevice> pairedDevices;
       private ListView myListView;
       private ArrayAdapter<String> BTArrayAdapter;

       @Override
       protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.test);

          // take an instance of BluetoothAdapter - Bluetooth radio
          myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
          if(myBluetoothAdapter == null) {
              onBtn.setEnabled(false);
              offBtn.setEnabled(false);
              listBtn.setEnabled(false);
              findBtn.setEnabled(false);
              text.setText("Status: not supported");

              Toast.makeText(getApplicationContext(),"Your device does not support Bluetooth",
                     Toast.LENGTH_LONG).show();
          } else {
              text = (TextView) findViewById(R.id.text);
              onBtn = (Button)findViewById(R.id.turnOn);
              onBtn.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    on(v);
                }
              });

              offBtn = (Button)findViewById(R.id.turnOff);
              offBtn.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    off(v);
                }
              });

              listBtn = (Button)findViewById(R.id.paired);
              listBtn.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    list(v);
                }
              });

              findBtn = (Button)findViewById(R.id.search);
              findBtn.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    find(v);
                }
              });

              myListView = (ListView)findViewById(R.id.listView1);

              // create the arrayAdapter that contains the BTDevices, and set it to the ListView
              BTArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1);
              myListView.setAdapter(BTArrayAdapter);

          }
       }

       public void on(View view){
          if (!myBluetoothAdapter.isEnabled()) {
             Intent turnOnIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
             startActivityForResult(turnOnIntent, REQUEST_ENABLE_BT);

             Toast.makeText(getApplicationContext(),"Bluetooth turned on" ,
                     Toast.LENGTH_LONG).show();
          }
          else{
             Toast.makeText(getApplicationContext(),"Bluetooth is already on",
                     Toast.LENGTH_LONG).show();
          }
       }

       @Override
       protected void onActivityResult(int requestCode, int resultCode, Intent data) {
           // TODO Auto-generated method stub
           if(requestCode == REQUEST_ENABLE_BT){
               if(myBluetoothAdapter.isEnabled()) {
                   text.setText("Status: Enabled");
               } else {   
                   text.setText("Status: Disabled");
               }
           }
       }

       public void list(View view){
          // get paired devices
          pairedDevices = myBluetoothAdapter.getBondedDevices();

          // put it's one to the adapter
          for(BluetoothDevice device : pairedDevices)
              BTArrayAdapter.add(device.getName()+ "\n" + device.getAddress());

          Toast.makeText(getApplicationContext(),"Show Paired Devices",
                  Toast.LENGTH_SHORT).show();

       }

       final BroadcastReceiver bReceiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                String action = intent.getAction();
                // When discovery finds a device
                if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                     // Get the BluetoothDevice object from the Intent
                     BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                     // add the name and the MAC address of the object to the arrayAdapter
                     BTArrayAdapter.add(device.getName() + "\n" + device.getAddress());
                     BTArrayAdapter.notifyDataSetChanged();
                }
            }
        };

       public void find(View view) {
           if (myBluetoothAdapter.isDiscovering()) {
               // the button is pressed when it discovers, so cancel the discovery
               myBluetoothAdapter.cancelDiscovery();
           }
           else {
                BTArrayAdapter.clear();
                myBluetoothAdapter.startDiscovery();

                registerReceiver(bReceiver, new IntentFilter(BluetoothDevice.ACTION_FOUND));    
            }    
       }

       public void off(View view){
          myBluetoothAdapter.disable();
          text.setText("Status: Disconnected");

          Toast.makeText(getApplicationContext(),"Bluetooth turned off",
                  Toast.LENGTH_LONG).show();
       }

       @Override
       protected void onDestroy() {
           // TODO Auto-generated method stub
           super.onDestroy();
           unregisterReceiver(bReceiver);
       }
    }

android bluetooth

asked by Randall Sandoval 19.02.2016 в 13:26

source

1 answer

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score 4 · Answer 1

Apparently you have not even established a connection to start:

Defines a global variable of BluetoothSocket in Activity

private BluetoothSocket mBluetoothSocket;

Then define a global variable for the identifier:

private UUID bluetoothUUID = UUID.fromString("ejemplo");

Replace "ejemplo" with an automatically generated UUID.

Start with a Thread to connect

private class ConnectThread extends Thread {

    public ConnectThread(BluetoothDevice device) {
        try {
            mBluetoothSocket = device.createRfcommSocketToServiceRecord(device, bluetoothUUID);
        } catch (IOException e) {
            Log.e(TAG, "Error de variables:" + e.getMessage(), e);
        }
    }

    public void run() {
        try {
            mBluetoothSocket.connect();
            while (true) {
                if (mBluetoothSocket != null) {
                    mStreamThread = new StreamThread();
                    mStreamThread.start();
                    break;
                }
            }
        } catch (IOException e) {
            Log.e(TAG, "Conexión fallida:" + e.getMessage(), e);
        }
    }

}

Then create a Thread to accept connections.

private class AcceptThread extends Thread {

    private BluetoothServerSocket mServerSocket;

    public AcceptThread(String name) {
        try {
            mServerSocket = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(name, bluetoothUUID);
        } catch (IOException e) {
            Log.e(TAG, "Error de variables:" + e.getMessage(), e);
        }
    }

    public void run() {
        while (true) {
            try {
                mBluetoothSocket = mServerSocket.accept();
                if (mBluetoothSocket != null) {
                    mStreamThread = new Streamthread();
                    mStreamThread.start();
                    break;
                }
            } catch (IOException e) {
                Log.e(TAG, "Fallido:" + e.getMessage(), e);
            }
        }
    }

At the end we created the Thread mentioned in the previous 2

private class StreamThread extends Thread {

    private InputStream in;
    private OutputStream out;

    public StreamThread() {
        try {
            in = mBluetoothSocket.getInputStream();
            out = mBluetoothSocket.getOutputStream();
        } catch (IOException e) {
            Log.e(TAG, "Error de variables:" + e.getMessage(), e);
        }
    }

    public void run() {
        byte[] data = new byte[1024];
        int length;
        while (true) {
            try {
                length = in.read(data);
                String text = new String(data, 0, length);
                Log.i(TAG, "Texto:" + text);
            } catch (IOException e) {
                Log.e(TAG, "Posible conexión perdida:" + e.getMessage(), e);
                break;
            }
        }

    }

    public void write(byte[] data) throws IOException {
        out.write(data);
    }

}

To send data, such as "text", use the Thread of stream.

String text = "Ejemplo";
mStreamThread.write(text.getBytes());

When starting the activity ( Activity ), you must start the Thread of accepting.

AcceptThread accept = new AcceptThread("Ejemplo");
accept.start();

When connecting to a device, use the following Thread to connect.

ConnectThread connect = new ConnectThread(device);
connect.start();

Where you say device you must have an object BluetoothDevice .