Easy Blue Printer #

A Flutter plugin for Bluetooth thermal printers. Scan, connect, and print text or images with just a few lines of code.

English | Portugues

English #

Features #

• Scan nearby Bluetooth devices
• Connect and disconnect from printers
• Print text with font size, alignment, and bold options
• Print images from bytes
• Print empty lines (paper feed)
• Check connection status
• Works on Android and iOS

Supported Platforms #

Installation #

Add to your pubspec.yaml:

dependencies:
  easy_blue_printer: ^latest_version

Then run:

flutter pub get

Platform Setup #

Android #

Add these permissions to android/app/src/main/AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android">

    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
    <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />

    <application ...>

On Android 12+ the plugin automatically requests runtime permissions.

iOS #

Add these keys to ios/Runner/Info.plist:

<key>NSBluetoothAlwaysUsageDescription</key>
<string>This app needs Bluetooth to connect to printers</string>

<key>NSBluetoothPeripheralUsageDescription</key>
<string>This app needs Bluetooth to connect to printers</string>

Quick Start #

import 'package:easy_blue_printer/easy_blue_printer.dart';

final printer = EasyBluePrinter.instance;

// 1. Scan for devices
final devices = await printer.getPairedDevices();

// 2. Connect to a device
final connected = await printer.connectToDevice(devices.first);

// 3. Print text
await printer.printData(
  data: 'Hello, World!',
  fontSize: FS.medium,
  textAlign: TA.center,
  bold: true,
);

// 4. Feed paper
await printer.printEmptyLine(callTimes: 5);

// 5. Disconnect
await printer.disconnectFromDevice();

API Reference #

EasyBluePrinter.instance #

Singleton instance. Use this to access all methods.

getPairedDevices() #

Scans and returns a list of available Bluetooth devices.

Future<List<BluetoothDevice>> getPairedDevices()

Returns: List of BluetoothDevice objects with name and address properties.

connectToDevice(device) #

Connects to a Bluetooth printer.

Future<bool> connectToDevice(BluetoothDevice device)

Returns: true if connected successfully.

disconnectFromDevice() #

Disconnects from the current printer.

Future<bool> disconnectFromDevice()

Returns: true if disconnected successfully.

printData(...) #

Prints formatted text.

Future<bool> printData({
  required String data,
  required FS fontSize,
  required TA textAlign,
  required bool bold,
})

Returns: true if printed successfully.

printEmptyLine(callTimes) #

Feeds paper by printing empty lines.

Future<void> printEmptyLine({required int callTimes})

printImage(bytes, textAlign) #

Prints an image on the thermal printer.

Future<bool> printImage({
  required Uint8List bytes,
  required TA textAlign,
})

Returns: true if printed successfully.

Example — print from assets:

import 'package:flutter/services.dart';

final byteData = await rootBundle.load('assets/images/logo.png');
final bytes = byteData.buffer.asUint8List();

await printer.printImage(bytes: bytes, textAlign: TA.center);

isConnected() #

Checks if a printer is currently connected.

Future<bool> isConnected()

Returns: true if connected.

Enums #

FS — Font Size #

TA — Text Alignment #

Complete Example #

import 'package:easy_blue_printer/easy_blue_printer.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(home: const PrinterPage());
  }
}

class PrinterPage extends StatefulWidget {
  const PrinterPage({super.key});

  @override
  State<PrinterPage> createState() => _PrinterPageState();
}

class _PrinterPageState extends State<PrinterPage> {
  final printer = EasyBluePrinter.instance;

  List<BluetoothDevice> devices = [];
  bool isConnected = false;
  bool isLoading = false;

  Future<void> scan() async {
    setState(() => isLoading = true);
    devices = await printer.getPairedDevices();
    setState(() => isLoading = false);
  }

  Future<void> connect(BluetoothDevice device) async {
    setState(() => isLoading = true);
    isConnected = await printer.connectToDevice(device);
    setState(() => isLoading = false);
  }

  Future<void> printReceipt() async {
    await printer.printData(
      data: 'My Store',
      fontSize: FS.large,
      textAlign: TA.center,
      bold: true,
    );
    await printer.printData(
      data: '------------------------',
      fontSize: FS.normal,
      textAlign: TA.center,
      bold: false,
    );
    await printer.printData(
      data: 'Item 1          R$ 10.00',
      fontSize: FS.normal,
      textAlign: TA.left,
      bold: false,
    );
    await printer.printData(
      data: 'Item 2          R$ 25.00',
      fontSize: FS.normal,
      textAlign: TA.left,
      bold: false,
    );
    await printer.printData(
      data: '------------------------',
      fontSize: FS.normal,
      textAlign: TA.center,
      bold: false,
    );
    await printer.printData(
      data: 'TOTAL           R$ 35.00',
      fontSize: FS.medium,
      textAlign: TA.left,
      bold: true,
    );
    await printer.printEmptyLine(callTimes: 5);
  }

  Future<void> disconnect() async {
    await printer.disconnectFromDevice();
    setState(() => isConnected = false);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Printer Example')),
      body: Column(
        children: [
          // Scan button
          Padding(
            padding: const EdgeInsets.all(16),
            child: ElevatedButton(
              onPressed: isLoading ? null : scan,
              child: isLoading
                  ? const CircularProgressIndicator()
                  : const Text('Scan Devices'),
            ),
          ),

          // Device list
          Expanded(
            child: ListView.builder(
              itemCount: devices.length,
              itemBuilder: (context, index) {
                final device = devices[index];
                return ListTile(
                  title: Text(device.name),
                  subtitle: Text(device.address),
                  onTap: () => connect(device),
                );
              },
            ),
          ),

          // Print and disconnect buttons
          if (isConnected) ...[
            ElevatedButton(
              onPressed: printReceipt,
              child: const Text('Print Receipt'),
            ),
            TextButton(
              onPressed: disconnect,
              child: const Text('Disconnect'),
            ),
            const SizedBox(height: 16),
          ],
        ],
      ),
    );
  }
}

Donations #

If this package helped you, consider buying me a coffee!

PIX: 17ec92dc-89cf-4eb9-be90-8cab0fc2460c

Contributing #

Contributions are welcome! Feel free to open a PR or report issues on the repository.

License #

This project is distributed under the MIT license. See the LICENSE file for details.

Portugues #

Funcionalidades #

• Escanear dispositivos Bluetooth
• Conectar e desconectar de impressoras
• Imprimir texto com tamanho de fonte, alinhamento e negrito
• Imprimir imagens a partir de bytes
• Imprimir linhas em branco (alimentar papel)
• Verificar status da conexao
• Funciona no Android e iOS

Plataformas Suportadas #

Instalacao #

Adicione no seu pubspec.yaml:

dependencies:
  easy_blue_printer: ^latest_version

Depois execute:

flutter pub get

Configuracao por Plataforma #

Android #

Adicione estas permissoes no android/app/src/main/AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android">

    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
    <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />

    <application ...>

No Android 12+ o plugin solicita as permissoes automaticamente em tempo de execucao.

iOS #

Adicione estas chaves no ios/Runner/Info.plist:

<key>NSBluetoothAlwaysUsageDescription</key>
<string>Este app precisa do Bluetooth para conectar a impressoras</string>

<key>NSBluetoothPeripheralUsageDescription</key>
<string>Este app precisa do Bluetooth para conectar a impressoras</string>

Inicio Rapido #

import 'package:easy_blue_printer/easy_blue_printer.dart';

final printer = EasyBluePrinter.instance;

// 1. Escanear dispositivos
final devices = await printer.getPairedDevices();

// 2. Conectar a um dispositivo
final connected = await printer.connectToDevice(devices.first);

// 3. Imprimir texto
await printer.printData(
  data: 'Ola, Mundo!',
  fontSize: FS.medium,
  textAlign: TA.center,
  bold: true,
);

// 4. Alimentar papel
await printer.printEmptyLine(callTimes: 5);

// 5. Desconectar
await printer.disconnectFromDevice();

Referencia da API #

EasyBluePrinter.instance #

Instancia singleton. Use para acessar todos os metodos.

getPairedDevices() #

Escaneia e retorna uma lista de dispositivos Bluetooth disponiveis.

Future<List<BluetoothDevice>> getPairedDevices()

Retorno: Lista de objetos BluetoothDevice com as propriedades name e address.

connectToDevice(device) #

Conecta a uma impressora Bluetooth.

Future<bool> connectToDevice(BluetoothDevice device)

Retorno: true se conectou com sucesso.

disconnectFromDevice() #

Desconecta da impressora atual.

Future<bool> disconnectFromDevice()

Retorno: true se desconectou com sucesso.

printData(...) #

Imprime texto formatado.

Future<bool> printData({
  required String data,
  required FS fontSize,
  required TA textAlign,
  required bool bold,
})

Retorno: true se imprimiu com sucesso.

printEmptyLine(callTimes) #

Alimenta o papel imprimindo linhas em branco.

Future<void> printEmptyLine({required int callTimes})

printImage(bytes, textAlign) #

Imprime uma imagem na impressora termica.

Future<bool> printImage({
  required Uint8List bytes,
  required TA textAlign,
})

Retorno: true se imprimiu com sucesso.

Exemplo — imprimir dos assets:

import 'package:flutter/services.dart';

final byteData = await rootBundle.load('assets/images/logo.png');
final bytes = byteData.buffer.asUint8List();

await printer.printImage(bytes: bytes, textAlign: TA.center);

isConnected() #

Verifica se uma impressora esta conectada.

Future<bool> isConnected()

Retorno: true se estiver conectado.

Enums #

FS — Tamanho da Fonte #

TA — Alinhamento do Texto #

Exemplo Completo #

import 'package:easy_blue_printer/easy_blue_printer.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(home: const PrinterPage());
  }
}

class PrinterPage extends StatefulWidget {
  const PrinterPage({super.key});

  @override
  State<PrinterPage> createState() => _PrinterPageState();
}

class _PrinterPageState extends State<PrinterPage> {
  final printer = EasyBluePrinter.instance;

  List<BluetoothDevice> devices = [];
  bool isConnected = false;
  bool isLoading = false;

  Future<void> scan() async {
    setState(() => isLoading = true);
    devices = await printer.getPairedDevices();
    setState(() => isLoading = false);
  }

  Future<void> connect(BluetoothDevice device) async {
    setState(() => isLoading = true);
    isConnected = await printer.connectToDevice(device);
    setState(() => isLoading = false);
  }

  Future<void> printReceipt() async {
    await printer.printData(
      data: 'Minha Loja',
      fontSize: FS.large,
      textAlign: TA.center,
      bold: true,
    );
    await printer.printData(
      data: '------------------------',
      fontSize: FS.normal,
      textAlign: TA.center,
      bold: false,
    );
    await printer.printData(
      data: 'Item 1          R\$ 10,00',
      fontSize: FS.normal,
      textAlign: TA.left,
      bold: false,
    );
    await printer.printData(
      data: 'Item 2          R\$ 25,00',
      fontSize: FS.normal,
      textAlign: TA.left,
      bold: false,
    );
    await printer.printData(
      data: '------------------------',
      fontSize: FS.normal,
      textAlign: TA.center,
      bold: false,
    );
    await printer.printData(
      data: 'TOTAL           R\$ 35,00',
      fontSize: FS.medium,
      textAlign: TA.left,
      bold: true,
    );
    await printer.printEmptyLine(callTimes: 5);
  }

  Future<void> disconnect() async {
    await printer.disconnectFromDevice();
    setState(() => isConnected = false);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Exemplo Impressora')),
      body: Column(
        children: [
          // Botao de escanear
          Padding(
            padding: const EdgeInsets.all(16),
            child: ElevatedButton(
              onPressed: isLoading ? null : scan,
              child: isLoading
                  ? const CircularProgressIndicator()
                  : const Text('Escanear Dispositivos'),
            ),
          ),

          // Lista de dispositivos
          Expanded(
            child: ListView.builder(
              itemCount: devices.length,
              itemBuilder: (context, index) {
                final device = devices[index];
                return ListTile(
                  title: Text(device.name),
                  subtitle: Text(device.address),
                  onTap: () => connect(device),
                );
              },
            ),
          ),

          // Botoes de imprimir e desconectar
          if (isConnected) ...[
            ElevatedButton(
              onPressed: printReceipt,
              child: const Text('Imprimir Recibo'),
            ),
            TextButton(
              onPressed: disconnect,
              child: const Text('Desconectar'),
            ),
            const SizedBox(height: 16),
          ],
        ],
      ),
    );
  }
}

Doacoes #

Se este pacote te ajudou, considere me pagar um cafe!

PIX: 17ec92dc-89cf-4eb9-be90-8cab0fc2460c

Contribuindo #

Contribuicoes sao bem-vindas! Sinta-se a vontade para abrir um PR ou reportar problemas no repositorio.

Licenca #

Este projeto e distribuido sob a licenca MIT. Veja o arquivo LICENSE para mais detalhes.