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 both iOS and Android.(for example, Gprinter pt-280、pt-380、gp-1324、gp-2120 eg.),
now support tspl、cpcl、esc image print， If this plugin is helpful to you, please give it a like，Thanks.
| 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 | :white_check_mark: | :white_check_mark: | Starts a scan for Bluetooth Low Energy devices. |
| connect | :white_check_mark: | :white_check_mark: | Establishes a connection to the device. |
| disconnect | :white_check_mark: | :white_check_mark: | Cancels an active or pending connection to the device. |
| state | :white_check_mark: | :white_check_mark: | Stream of state changes for the Bluetooth Device. |
Tsc Command
| Android | iOS | Description | |
|---|---|---|---|
| size | :white_check_mark: | :white_check_mark: | Set label size in millimeters |
| selfTest | :white_check_mark: | :white_check_mark: | Print self inspection page information |
| :white_check_mark: | :white_check_mark: | Print out data stored in the buffer | |
| gap | :white_check_mark: | :white_check_mark: | Define the vertical spacing distance between two label papers. |
| speed | :white_check_mark: | :white_check_mark: | Set printing speed |
| density | :white_check_mark: | :white_check_mark: | Set printing concentration |
| cls | :white_check_mark: | :white_check_mark: | Clear data from image buffer |
| text | :white_check_mark: | :white_check_mark: | print string |
| image | :white_check_mark: | :white_check_mark: | print image |
| barCode | :white_check_mark: | :white_check_mark: | This instruction is used to draw one-dimensional barcodes |
| qrCode | :white_check_mark: | :white_check_mark: | This instruction is used to print QR codes |
| bar | :white_check_mark: | :white_check_mark: | This instruction is used to draw lines on labels |
| box | :white_check_mark: | :white_check_mark: | This instruction is used to draw a rectangular box on a label |
Usage
To use this plugin :
- add the dependency to your pubspec.yaml file.
dependencies:
flutter:
sdk: flutter
bluetooth_print_plus:
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_COARSE_LOCATION"/>
<application
IOS
In the ios/Runner/Info.plist let’s add:
<dict>
<key>NSBluetoothAlwaysUsageDescription</key>
<string>Need BLE permission</string>
<key>NSBluetoothPeripheralUsageDescription</key>
<string>Need BLE permission</string>
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>Need Location permission</string>
<key>NSLocationAlwaysUsageDescription</key>
<string>Need Location permission</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>Need Location permission</string>
For location permissions on iOS see more at: https://developer.apple.com/documentation/corelocation/requesting_authorization_for_location_services
init a BluetoothPrint instance
import 'package:bluetooth_print_plus/bluetooth_print_plus.dart';
import 'package:bluetooth_print/bluetooth_print_model.dart';
final _bluetoothPrintPlus = BluetoothPrintPlus.instance;
scan
// begin scan
_bluetoothPrintPlus.startScan(timeout: const Duration(seconds: 30));
// 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: [
Expanded(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(d.name ?? ''),
Text(
d.address ?? 'null',
overflow: TextOverflow.ellipsis,
style: const TextStyle(
fontSize: 12,
color: Colors.grey
),
),
const Divider(),
],
)
),
const SizedBox(width: 10,),
ElevatedButton(
onPressed: () async {
_bluetoothPrintPlus.stopScan();
_bluetoothPrintPlus.connect(d);
_device = d;
},
child: const Text("connect"),
)
],
),
)).toList(),
),
)
connect
await _bluetoothPrintPlus.connect(_device);
disconnect
await _bluetoothPrintPlus.disconnect();
or
await BluetoothPrintPlus.instance.disconnect();
listen state
_bluetoothPrintPlus.state.listen((state) {
print('cur device status: $state');
switch (state) {
case BluetoothPrint.CONNECTED:
setState(() {
_connected = true;
});
break;
case BluetoothPrint.DISCONNECTED:
setState(() {
_connected = false;
});
break;
default:
break;
}
});
print (tsc command, label mode)
final ByteData bytes = await rootBundle.load("assets/dithered-image.png");
final Uint8List image = bytes.buffer.asUint8List();
await tscCommand.cleanCommand();
await tscCommand.cls();
await tscCommand.size(width: 76, height: 130);
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);
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>
FAQ Support
you can join this QQ group or join TG group, feedback your problem
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