Android bluetooth printer application

This app will print messages to bluetooth enabled printer. Android printing protocols are very easy to understand. Printing text message is very easy but if you want to print file or image, you need to write your own method to convert image/file to printable format byte codes.

Create a new android project BlueToothPrinterApp in your editor.

Step 1:

Create main activity like below

com.example.BlueToothPrinterApp/BlueToothPrinterApp.java

package com.example.BlueToothPrinterApp;

import android.app.Activity;
import android.os.Bundle;
import java.io.IOException;
import java.io.OutputStream;
import android.bluetooth.BluetoothSocket;
import android.content.ContentValues;
import android.content.Intent;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class BlueToothPrinterApp extends Activity
{
/** Called when the activity is first created. */
EditText message;
Button printbtn;

byte FONT_TYPE;
private static BluetoothSocket btsocket;
private static OutputStream btoutputstream;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
message = (EditText)findViewById(R.id.message);
printbtn = (Button)findViewById(R.id.printButton);

printbtn.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
connect();
}
});
}

protected void connect() {
if(btsocket == null){
Intent BTIntent = new Intent(getApplicationContext(), BTDeviceList.class);
this.startActivityForResult(BTIntent, BTDeviceList.REQUEST_CONNECT_BT);
}
else{

OutputStream opstream = null;
try {
opstream = btsocket.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
}
btoutputstream = opstream;
print_bt();

}

}
private void print_bt() {
try {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}

btoutputstream = btsocket.getOutputStream();

byte[] printformat = { 0x1B, 0x21, FONT_TYPE };
btoutputstream.write(printformat);
String msg = message.getText().toString();
btoutputstream.write(msg.getBytes());
btoutputstream.write(0x0D);
btoutputstream.write(0x0D);
btoutputstream.write(0x0D);
btoutputstream.flush();
} catch (IOException e) {
e.printStackTrace();
}

}

@Override
protected void onDestroy() {
super.onDestroy();
try {
if(btsocket!= null){
btoutputstream.close();
btsocket.close();
btsocket = null;
}
} catch (IOException e) {
e.printStackTrace();
}
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
try {
btsocket = BTDeviceList.getSocket();
if(btsocket != null){
print_bt();
}

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

Step 2:

com.example.BlueToothPrinterApp/BTDeviceList.java

package com.example.BlueToothPrinterApp;

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

import android.app.ListActivity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
public class BTDeviceList extends ListActivity {

static public final int REQUEST_CONNECT_BT = 0x2300;

static private final int REQUEST_ENABLE_BT = 0x1000;

static private BluetoothAdapter mBluetoothAdapter = null;

static private ArrayAdapter<String> mArrayAdapter = null;

static private ArrayAdapter<BluetoothDevice> btDevices = null;

private static final UUID SPP_UUID = UUID
.fromString(“8ce255c0-200a-11e0-ac64-0800200c9a66″);
// UUID.fromString(“00001101-0000-1000-8000-00805F9B34FB”);

static private BluetoothSocket mbtSocket = null;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setTitle(“Bluetooth Devices”);

try {
if (initDevicesList() != 0) {
this.finish();
return;
}

} catch (Exception ex) {
this.finish();
return;
}

IntentFilter btIntentFilter = new IntentFilter(
BluetoothDevice.ACTION_FOUND);
registerReceiver(mBTReceiver, btIntentFilter);
}

public static BluetoothSocket getSocket() {
return mbtSocket;
}

private void flushData() {
try {
if (mbtSocket != null) {
mbtSocket.close();
mbtSocket = null;
}

if (mBluetoothAdapter != null) {
mBluetoothAdapter.cancelDiscovery();
}

if (btDevices != null) {
btDevices.clear();
btDevices = null;
}

if (mArrayAdapter != null) {
mArrayAdapter.clear();
mArrayAdapter.notifyDataSetChanged();
mArrayAdapter.notifyDataSetInvalidated();
mArrayAdapter = null;
}

finalize();

} catch (Exception ex) {
} catch (Throwable e) {
}

}
private int initDevicesList() {

flushData();

mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
Toast.makeText(getApplicationContext(),
“Bluetooth not supported!!”, Toast.LENGTH_LONG).show();
return -1;
}

if (mBluetoothAdapter.isDiscovering()) {
mBluetoothAdapter.cancelDiscovery();
}

mArrayAdapter = new ArrayAdapter<String>(getApplicationContext(),
android.R.layout.simple_list_item_1);

setListAdapter(mArrayAdapter);

Intent enableBtIntent = new Intent(
BluetoothAdapter.ACTION_REQUEST_ENABLE);
try {
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
} catch (Exception ex) {
return -2;
}

Toast.makeText(getApplicationContext(),
“Getting all available Bluetooth Devices”, Toast.LENGTH_SHORT)
.show();

return 0;

}

@Override
protected void onActivityResult(int reqCode, int resultCode, Intent intent) {
super.onActivityResult(reqCode, resultCode, intent);

switch (reqCode) {
case REQUEST_ENABLE_BT:

if (resultCode == RESULT_OK) {
Set<BluetoothDevice> btDeviceList = mBluetoothAdapter
.getBondedDevices();
try {
if (btDeviceList.size() > 0) {

for (BluetoothDevice device : btDeviceList) {
if (btDeviceList.contains(device) == false) {

btDevices.add(device);

mArrayAdapter.add(device.getName() + “\n”
+ device.getAddress());
mArrayAdapter.notifyDataSetInvalidated();
}
}
}
} catch (Exception ex) {
}
}

break;
}

mBluetoothAdapter.startDiscovery();

}

private final BroadcastReceiver mBTReceiver = new BroadcastReceiver() {

@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
BluetoothDevice device = intent
.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

try {
if (btDevices == null) {
btDevices = new ArrayAdapter<BluetoothDevice>(
getApplicationContext(), android.R.id.text1);
}

if (btDevices.getPosition(device) < 0) {
btDevices.add(device);
mArrayAdapter.add(device.getName() + “\n”
+ device.getAddress() + “\n” );
mArrayAdapter.notifyDataSetInvalidated();
}
} catch (Exception ex) {
// ex.fillInStackTrace();
}
}
}
};

@Override
protected void onListItemClick(ListView l, View v, final int position,
long id) {
super.onListItemClick(l, v, position, id);

if (mBluetoothAdapter == null) {
return;
}

if (mBluetoothAdapter.isDiscovering()) {
mBluetoothAdapter.cancelDiscovery();
}

Toast.makeText(
getApplicationContext(),
“Connecting to ” + btDevices.getItem(position).getName() + “,”
+ btDevices.getItem(position).getAddress(),
Toast.LENGTH_SHORT).show();

Thread connectThread = new Thread(new Runnable() {

@Override
public void run() {
try {
boolean gotuuid = btDevices.getItem(position)
.fetchUuidsWithSdp();
UUID uuid = btDevices.getItem(position).getUuids()[0]
.getUuid();
mbtSocket = btDevices.getItem(position)
.createRfcommSocketToServiceRecord(uuid);

mbtSocket.connect();
} catch (IOException ex) {
runOnUiThread(socketErrorRunnable);
try {
mbtSocket.close();
} catch (IOException e) {
// e.printStackTrace();
}
mbtSocket = null;
return;
} finally {
runOnUiThread(new Runnable() {

@Override
public void run() {
finish();

}
});
}
}
});

connectThread.start();
}

private Runnable socketErrorRunnable = new Runnable() {

@Override
public void run() {
Toast.makeText(getApplicationContext(),
“Cannot establish connection”, Toast.LENGTH_SHORT).show();
mBluetoothAdapter.startDiscovery();

}
};

@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);

menu.add(0, Menu.FIRST, Menu.NONE, “Refresh Scanning”);

return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);

switch (item.getItemId()) {
case Menu.FIRST:
initDevicesList();
break;
}

return true;
}
}

Step 3:

Edit your main.xml file and paste below code.

res/layout/main.xml

<?xml version=”1.0″ encoding=”utf-8″?>
<RelativeLayout xmlns:android=”http://schemas.android.com/apk/res/android&#8221;
android:layout_width=”fill_parent”
android:layout_height=”fill_parent”
android:paddingLeft=”16dp”
android:paddingRight=”16dp” >

<TextView
android:id=”@+id/msgtextlbl”
android:layout_width=”match_parent”
android:layout_height=”wrap_content”
android:text=”Enter Your Message : ” >
</TextView>

<EditText
android:id=”@+id/message”
android:layout_width=”fill_parent”
android:layout_height=”100dp”
android:layout_below=”@+id/msgtextlbl”
android:text=”” >
</EditText>

<Button
android:id=”@+id/printButton”
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:layout_below=”@+id/message”
android:layout_marginTop=”5dip”
android:layout_centerHorizontal=”true”
android:text=”Print” >
</Button>
</RelativeLayout>

Step 4:

Now edit your AndroidManifest.xml

Add bluetooth permission and admin permission.

AndroidManifest.xml

<?xml version=”1.0″ encoding=”utf-8″?>
<manifest xmlns:android=”http://schemas.android.com/apk/res/android&#8221;
package=”com.example.BlueToothPrinterApp”
android:versionCode=”1″
android:versionName=”1.0″>
<application android:label=”@string/app_name” android:icon=”@drawable/ic_launcher”>
<activity android:name=”BlueToothPrinterApp”
android:label=”@string/app_name”>
<intent-filter>
<action android:name=”android.intent.action.MAIN” />
<category android:name=”android.intent.category.LAUNCHER” />
</intent-filter>
</activity>
<activity android:name=”BTDeviceList”></activity>
</application>
<uses-sdk android:minSdkVersion=”14″ />
<uses-permission android:name=”android.permission.BLUETOOTH”></uses-permission>
<uses-permission android:name=”android.permission.BLUETOOTH_ADMIN”></uses-permission>
</manifest>

Compile and run this application. Enter message and press print button.

You will see list of bluetooth devices. Select bluettoth printer.

Check print on your bluetooth printer.

:)

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