smart_bluetooth_pos_printer

A library to discover printers, and send printer commands.

This library allows to print esc commands to printers in different platforms such as android, ios, windows and different interfaces as Bluetooth and BLE

Inspired by flutter_pos_printer_platform.

Main Features

• Android, iOS and Windows support
• Scan for bluetooth devices
• Send raw List<int> bytes data to a device, review this library to generate ESC/POS commands flutter_esc_pos_utils.

Features

	Android	iOS	Windows	Description
Bluetooth classic interface	✅	🔳	🔳	Allows connection with classic bt devices.
Bluetooth low energy (BLE) interface	✅	✅	🔳	Allows connection with bt BLE devices.
scan	✅	✅	✅	Starts a scan for only Bluetooth devices or network devices(Android/iOS).
connect	✅	✅	✅	Establishes a connection to the device.
disconnect	✅	✅	✅	Cancels an active or pending connection to the device.
state	✅	✅	✅	Stream of state changes for the Bluetooth Device.
print	✅	✅	✅	print bytes.

Getting Started

For a full example please check /example folder. Here are only the most important parts of the code to illustrate how to use the library.

Generate bytes to print through flutter_esc_pos_utils.

    import 'package:esc_pos_utils/esc_pos_utils.dart';

    final profile = await CapabilityProfile.load();
    final generator = Generator(PaperSize.mm58, profile);
    List<int> bytes = [];

    bytes += generator.text('Test Print', styles: const PosStyles(align: PosAlign.center));
    bytes += generator.text('Product 1');
    bytes += generator.text('Product 2');

Android

Allow to connect bluetooth (classic and BLE), USB and network devices

Change the minSdkVersion for Android

smart_bluetooth_pos_printer is compatible only from version 21 of Android SDK so you should change this in android/app/build.gradle:

In build.gradle set

    defaultConfig {
        ...
        minSdkVersion 21
        targetSdkVersion 31
        ...

select type of device PrinterType ( bluetooth, usb, network)

if select bluetooth you can send optional params

• isBle -> allow to connect with bluetooth that supports this technology
• autoconnect -> allow to reconnect when state of device is None

iOS

Allow to connect bluetooth (BLE) and network devices

How to use it

init a PrinterManager instance

import 'package:smart_bluetooth_pos_printer/smart_bluetooth_pos_printer.dart';

    var printerManager = PrinterManager.instance;

scan

    var devices = [];
    _scan({bool isBle = false}) {
        // Find printers
        PrinterManager.instance.discovery(isBle: isBle).listen((device) {
            devices.add(device);
        });
    }

connect

_connectDevice(PrinterDevice selectedPrinter, {bool reconnect = false, bool isBle = false}) async {
    await printerManager.connect(
        model: BluetoothPrinterInput(
            name: selectedPrinter!.deviceName,
            address: selectedPrinter!.address!,
            isBle: selectedPrinter!.isBle ?? false,
            autoConnect: _reconnect));
  }

disconnect

    _disconnectDevice() async {
        await PrinterManager.instance.disconnect();
        }

listen bluetooth state

    PrinterManager.instance.stateBluetooth.listen((status) {
      log(' ----------------- status bt $status ------------------ ');
    });

send bytes to print

    _sendBytesToPrint(List<int> bytes) async { 
      PrinterManager.instance.send(bytes: bytes);
    }

Troubleshooting

error:'State restoration of CBCentralManager is only allowed for applications that have specified the "bluetooth-central" background mode' info.plist add:

<key>NSBluetoothAlwaysUsageDescription</key>
<string>Allow App use bluetooth?</string>
<key>NSBluetoothPeripheralUsageDescription</key>
<string>Allow App use bluetooth?</string>
<key>UIBackgroundModes</key>
<array>
    <string>bluetooth-central</string>
    <string>bluetooth-peripheral</string>
</array>

Support me

If you think that this project has helped you with your developments, you can support this project, any support is much appreciated.