bluetooth_print_plus 2.4.0

bluetooth_print_plus is a flutter plugin for bluetooth thermal printer, support Android & iOS, supports tspl/tsc、cpcl、esc pos.

Introduction

Bluetooth Print Plus is a Bluetooth plugin used to print thermal printers in Flutter, a new mobile SDK to help developers build bluetooth thermal printer apps for iOS and Android.

Important, important, important. First, you need to run the demo to confirm the printer command type ! ! ! now support tspl/tsc、cpcl、esc pos. If this plugin is helpful to you, please give it a like, Thanks.

FAQ Support

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Plan

Version	plan
1.1.x	blue and tsc command, esc print image command
1.5.x	support cpcl command
2.x.x	improve esc command
3.x.x	support zpl command

Features

	Android	iOS	Description
scan	✅	✅	Starts a scan for Bluetooth Low Energy devices.
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.

Usage

Example

To use this plugin :

• add the dependency to your pubspec.yaml file.

dependencies:
  flutter:
    sdk: flutter
  bluetooth_print_plus: ^2.4.0

Add permissions for Bluetooth

---

We need to add the permission to use Bluetooth and access location:

Android

In the android/app/src/main/AndroidManifest.xml let’s add:

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

IOS

In the ios/Runner/Info.plist let’s add:

<key>NSBluetoothAlwaysUsageDescription</key>
<string>Need BLE permission</string>
<key>NSBluetoothPeripheralUsageDescription</key>
<string>Need BLE permission</string>

init BluetoothPrintPlus instance

import 'package:bluetooth_print_plus/bluetooth_print_plus.dart';

final _bluetoothPrintPlus = BluetoothPrintPlus.instance;

BluetoothPrintPlus useful property

_bluetoothPrintPlus.isBlueOn;
_bluetoothPrintPlus.isScanning;
_bluetoothPrintPlus.isConnected;

listen

• state

/// listen blue state
_bluetoothPrintPlus.blueState.listen((event) {
  print('********** blueState change: $event **********');
  /// blue state changed, do something...
});

/// listen connect state
_bluetoothPrintPlus.connectState.listen((event) {
  print('********** connectState change: $event **********');
  /// connect state changed, do something...
});

• received Data

_bluetoothPrintPlus.receivedData.listen((data) {
  print('********** received data: $data **********');
  /// received data, do something...
});

scan

// begin scan
_bluetoothPrintPlus.startScan(timeout: const Duration(seconds: 8));

// get devices
StreamBuilder<List<BluetoothDevice>>(
  stream: _bluetoothPrintPlus.scanResults,
  initialData: [],
  builder: (c, snapshot) => ListView(
    children: snapshot.data!.map((d) => Container(
      padding: const EdgeInsets.only(left: 10, right: 10, bottom: 5),
      child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [ .... ],
          ),
    )).toList(),
  ),
)

connect

await _bluetoothPrintPlus.connect(_device);

disconnect

await _bluetoothPrintPlus.disconnect();
or
await  BluetoothPrintPlus.instance.disconnect();

print/write

/// for example: write tsc command
final ByteData bytes = await rootBundle.load("assets/dithered-image.png");
final Uint8List image = bytes.buffer.asUint8List();
await tscCommand.cleanCommand();
await tscCommand.size(width: 76, height: 130);
await tscCommand.cls(); // most after size
await tscCommand.image(image: image, x: 50, y: 60);
await tscCommand.print(1);
final cmd = await tscCommand.getCommand();
if (cmd == null) return;
BluetoothPrintPlus.instance.write(cmd);

/// for example: write cpcl command
await cpclCommand.cleanCommand();
await cpclCommand.size(width: 76 * 8, height: 76 * 8);
await cpclCommand.image(image: image, x: 10, y: 10);
await cpclCommand.print();
final cmd = await cpclCommand.getCommand();
if (cmd == null) return;
BluetoothPrintPlus.instance.write(cmd);

/// for example: write esc command
await escCommand.cleanCommand();
await escCommand.print();
await escCommand.image(image: image);
await escCommand.print();
final cmd = await escCommand.getCommand();
if (cmd == null) return;
BluetoothPrintPlus.instance.write(cmd);

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>

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