PrintActivty.java

package eu.ttbox.androgister.ui.print;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;

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.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import eu.ttbox.androgister.R;

public class PrintActivty extends Activity  {

    
    // will show the statuses
    TextView myLabel;
    
    // will enable user to enter any text to be printed
    EditText myTextbox;
    
    // android built in classes for bluetooth operations
    BluetoothAdapter mBluetoothAdapter;
    BluetoothSocket mmSocket;
    BluetoothDevice mmDevice;
    
    OutputStream mmOutputStream;
    InputStream mmInputStream;
    Thread workerThread;
    
    byte[] readBuffer;
    int readBufferPosition;
    int counter;
    volatile boolean stopWorker;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.print_activity);

        try {
            
            // we are goin to have three buttons for specific functions
            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 bluetooth connection
            openButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    try {
                        findBT();
                        openBT();
                    } catch (IOException ex) {
                    }
                }
            });

            // send data typed by the user to be printed
            sendButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    try {
                        sendData();
                    } catch (IOException ex) {
                    }
                }
            });

            // close bluetooth connection
            closeButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    try {
                        closeBT();
                    } catch (IOException ex) {
                    }
                }
            });

        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /*
     * This will find a bluetooth printer device
     */
    void findBT() {

        try {
            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) {
                    
                    // MP300 is the name of the bluetooth printer device
                    if (device.getName().equals("MP300")) {
                        mmDevice = device;
                        break;
                    }
                }
            }
            myLabel.setText("Bluetooth Device Found");
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /*
     * Tries to open a connection to the bluetooth printer device
     */
    void openBT() throws IOException {
        try {
            // Standard SerialPortService ID
            UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
            mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);
            mmSocket.connect();
            mmOutputStream = mmSocket.getOutputStream();
            mmInputStream = mmSocket.getInputStream();

            beginListenForData();

            myLabel.setText("Bluetooth Opened");
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    /*
     * After opening a connection to bluetooth printer device, 
     * we have to listen and check if a data were sent to be printed.
     */
    void beginListenForData() {
        try {
            final Handler handler = new Handler();
            
            // This is the ASCII code for a newline character
            final byte delimiter = 10;

            stopWorker = false;
            readBufferPosition = 0;
            readBuffer = new byte[1024];
            
            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++) {
                                    byte b = packetBytes[i];
                                    if (b == delimiter) {
                                        byte[] encodedBytes = new byte[readBufferPosition];
                                        System.arraycopy(readBuffer, 0,
                                                encodedBytes, 0,
                                                encodedBytes.length);
                                        final String data = new String(
                                                encodedBytes, "US-ASCII");
                                        readBufferPosition = 0;

                                        handler.post(new Runnable() {
                                            public void run() {
                                                myLabel.setText(data);
                                            }
                                        });
                                    } else {
                                        readBuffer[readBufferPosition++] = b;
                                    }
                                }
                            }
                            
                        } catch (IOException ex) {
                            stopWorker = true;
                        }
                        
                    }
                }
            });

            workerThread.start();
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /*
     * This will send data to be printed by the bluetooth printer
     */
    void sendData() throws IOException {
        try {
            
            // the text typed by the user
            String msg = myTextbox.getText().toString();
            msg += "\n";
            
            mmOutputStream.write(msg.getBytes());
            
            // tell the user data were sent
            myLabel.setText("Data Sent");
            
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /*
     * Close the connection to bluetooth printer.
     */
    void closeBT() throws IOException {
        try {
            stopWorker = true;
            mmOutputStream.close();
            mmInputStream.close();
            mmSocket.close();
            myLabel.setText("Bluetooth Closed");
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    
}