niim_blue_flutter 1.0.1 
niim_blue_flutter: ^1.0.1 copied to clipboard
Flutter library for BLE printing with NIIMBOT thermal printers. Supports 85+ printer models with automatic detection and rich content rendering.
import 'dart:io';
import 'dart:typed_data';
import 'package:device_info_plus/device_info_plus.dart';
import 'package:flutter/material.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';
import 'package:niim_blue_flutter/niim_blue_flutter.dart';
import 'package:permission_handler/permission_handler.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'NiimBlueLibRN',
theme: ThemeData(
useMaterial3: true,
colorScheme: ColorScheme.fromSeed(seedColor: Colors.blue),
),
home: const AppContent(),
);
}
}
class AppContent extends StatefulWidget {
const AppContent({super.key});
@override
State<AppContent> createState() => _AppContentState();
}
class _AppContentState extends State<AppContent> {
NiimbotBluetoothClient? _client;
String _status = 'Disconnected';
List<BluetoothDevice> _devices = [];
bool _showDeviceList = false;
Uint8List? _previewImage;
bool _showPreview = false;
Future<void> Function()? _pendingPrintAction;
Future<bool> _requestPermissions() async {
if (Platform.isIOS) {
// iOS doesn't need runtime permissions
// Bluetooth permissions are handled via Info.plist
return true;
}
// Android 12+ (SDK 31+) needs bluetoothScan and bluetoothConnect
// Older Android needs bluetooth and location
final androidInfo = await DeviceInfoPlugin().androidInfo;
if (androidInfo.version.sdkInt >= 31) {
final statuses = await [
Permission.bluetoothScan,
Permission.bluetoothConnect,
].request();
return statuses.values.every((status) => status.isGranted);
} else {
final statuses = await [
Permission.bluetooth,
Permission.location,
].request();
return statuses.values.every((status) => status.isGranted);
}
}
Future<void> _handleConnect() async {
final hasPermission = await _requestPermissions();
if (!hasPermission) {
if (mounted) {
_showAlert('Error', 'Bluetooth permissions are required');
}
return;
}
try {
setState(() {
_status = 'Scanning for devices...';
});
final foundDevices = await NiimbotBluetoothClient.listDevices(
timeout: const Duration(seconds: 3),
);
final connectedDevices = FlutterBluePlus.connectedDevices;
if (foundDevices.isEmpty && connectedDevices.isEmpty) {
if (mounted) {
_showAlert(
'No Devices Found',
'No compatible printers found. Make sure your printer is turned on and in pairing mode.',
);
setState(() => _status = 'No devices found');
}
return;
}
// Combine and deduplicate devices
final allDevices = [...foundDevices, ...connectedDevices];
final uniqueDevices = <BluetoothDevice>[];
final seenIds = <String>{};
for (final device in allDevices) {
final id = device.remoteId.str;
if (!seenIds.contains(id)) {
seenIds.add(id);
uniqueDevices.add(device);
}
}
setState(() {
_devices = uniqueDevices;
_showDeviceList = true;
_status = 'Select a device';
});
} catch (error) {
if (mounted) {
if (error.toString().contains('Bluetooth is not powered on')) {
_showAlert(
'Bluetooth Required',
'Please enable Bluetooth in your device settings and try connecting again.',
);
} else {
_showAlert('Error', error.toString());
}
setState(() => _status = 'Scan failed');
}
}
}
Future<void> _connectToDevice(BluetoothDevice device) async {
setState(() {
_showDeviceList = false;
_status = 'Connecting...';
});
try {
final client = NiimbotBluetoothClient();
client.setDevice(device);
final result = await client.connect();
setState(() {
_client = client;
_status = 'Connected to ${result.deviceName}';
});
_client!.startHeartbeat();
} catch (error) {
if (mounted) {
if (error.toString().contains('Bluetooth is not powered on')) {
_showAlert(
'Bluetooth Required',
'Please enable Bluetooth in your device settings and try connecting again.',
);
} else {
_showAlert('Error', error.toString());
}
setState(() => _status = 'Connection failed');
}
}
}
Future<void> _handleDisconnect() async {
if (_client == null) return;
try {
await _client!.abstraction.printEnd();
await _client!.disconnect();
setState(() {
_status = 'Disconnected';
_client = null;
});
} catch (error) {
_showAlert('Error', 'Failed to disconnect: ${error.toString()}');
}
}
Future<void> _showPreviewAndPrint(
PrintPage page,
Future<void> Function() printAction,
) async {
try {
final imageData = await page.toPreviewImage();
setState(() {
_previewImage = imageData;
_pendingPrintAction = printAction;
_showPreview = true;
});
} catch (error) {
_showAlert('Error', 'Failed to generate preview: ${error.toString()}');
}
}
Future<void> _executePrint() async {
setState(() => _showPreview = false);
if (_client == null || !_client!.isConnected()) {
_showAlert('Error', 'Not connected');
setState(() => _pendingPrintAction = null);
return;
}
if (_pendingPrintAction != null) {
await _pendingPrintAction!();
setState(() => _pendingPrintAction = null);
}
}
Future<void> _executePrintTask(PrintPage page, String successMessage) async {
if (_client == null || !_client!.isConnected()) {
throw Exception('Not connected');
}
try {
_client!.stopHeartbeat();
_client!.packetIntervalMs = 0;
final task = _client!.createPrintTask(
const PrintOptions(
totalPages: 1,
density: 3,
labelType: LabelType.withGaps,
statusPollIntervalMs: 100,
statusTimeoutMs: 8000,
),
);
if (task == null) {
throw Exception(
'Failed to create print task - printer model not detected',
);
}
await task.printInit();
await task.printPage(page.toEncodedImage(), 1);
await task.waitForFinished();
_client!.startHeartbeat();
if (mounted) {
_showAlert('Success', successMessage);
}
} catch (error) {
_client!.startHeartbeat();
if (mounted) {
_showAlert('Error', 'Failed to print: ${error.toString()}');
}
}
}
Future<void> _handlePrint() async {
if (_client == null || !_client!.isConnected()) {
_showAlert('Error', 'Not connected');
return;
}
final page = PrintPage(8, 1);
for (int i = 0; i < 8; i++) {
page.addLine(
const LineOptions(x: 0, y: 0, endX: 0, endY: 0, thickness: 1));
}
await _executePrintTask(page, 'Print sent');
}
Future<void> _handlePrintSimple() async {
// Simple demo without text rendering - just QR and barcode
final page = PrintPage(400, 240);
page.addQR(
'Hello Niimbot',
const QROptions(
x: 100,
y: 120,
width: 100,
height: 100,
align: HAlignment.center,
vAlign: VAlignment.middle,
),
);
page.addBarcode(
'123456789012',
const BarcodeOptions(
encoding: BarcodeEncoding.ean13,
x: 300,
y: 120,
width: 150,
height: 60,
align: HAlignment.center,
vAlign: VAlignment.middle,
),
);
await _showPreviewAndPrint(page, () async {
await _executePrintTask(page, 'Simple demo printed');
});
}
Future<void> _handlePrintBoldText() async {
final page = PrintPage(400, 240);
await page.addText(
'Normal Text',
const TextOptions(
x: 200,
y: 60,
fontSize: 18,
align: HAlignment.center,
vAlign: VAlignment.middle,
));
await page.addText(
'Bold Text',
const TextOptions(
x: 200,
y: 120,
fontSize: 18,
fontWeight: FontWeight.bold,
align: HAlignment.center,
vAlign: VAlignment.middle,
));
await page.addText(
'Light Text',
const TextOptions(
x: 200,
y: 180,
fontSize: 18,
fontWeight: FontWeight.w300,
align: HAlignment.center,
vAlign: VAlignment.middle,
));
await _showPreviewAndPrint(page, () async {
await _executePrintTask(page, 'Styled text printed');
});
}
Future<void> _handlePrintLandscape() async {
final page = PrintPage(320, 480, PageOrientation.landscape);
page.addQR(
'Landscape',
const QROptions(
x: 240,
y: 240,
width: 80,
height: 80,
align: HAlignment.center,
vAlign: VAlignment.middle,
),
);
page.addBarcode(
'987654321098',
const BarcodeOptions(
encoding: BarcodeEncoding.code128,
x: 240,
y: 80,
width: 200,
height: 60,
align: HAlignment.center,
vAlign: VAlignment.middle,
),
);
page.addLine(
const LineOptions(x: 40, y: 300, endX: 440, endY: 300, thickness: 2));
await page.addText(
'LANDSCAPE MODE',
const TextOptions(
x: 240,
y: 160,
fontSize: 24,
align: HAlignment.center,
vAlign: VAlignment.middle,
));
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page.addPixelData(
ImageOptions(
data: heartData,
imageWidth: 16,
imageHeight: 11,
x: 480,
y: 0,
width: 80,
height: 80,
align: HAlignment.right,
vAlign: VAlignment.top,
),
);
// Add image from URL (async)
try {
await page.addImageFromUri(
'https://fastly.picsum.photos/id/1/100/100.jpg?hmac=ZFE9J9JWYx84uJzvjw4GTuagMzN4FAmaKE4XeJDMZTY',
const ImageFromBufferOptions(
x: 0,
y: 0,
width: 100,
height: 70,
align: HAlignment.left,
vAlign: VAlignment.top,
threshold: 128,
),
);
} catch (e) {
print('Failed to load image from URL: $e');
}
await _showPreviewAndPrint(page, () async {
await _executePrintTask(page, 'Landscape page printed');
});
}
Future<void> _handlePrintComprehensive() async {
final page = PrintPage(400, 240);
// QR Code top left with rotation
page.addQR(
'Hello QR',
const QROptions(
x: 60,
y: 60,
width: 80,
height: 80,
align: HAlignment.center,
vAlign: VAlignment.middle,
rotate: 15,
),
);
await page.addText(
'Hello NIIMBOT!',
const TextOptions(
x: 200,
y: 120,
fontSize: 32,
fontWeight: FontWeight.bold,
align: HAlignment.center,
vAlign: VAlignment.middle,
));
await page.addText(
'v1.0',
const TextOptions(
x: 350,
y: 30,
fontSize: 20,
fontWeight: FontWeight.bold,
align: HAlignment.center,
vAlign: VAlignment.middle,
rotate: 45,
),
);
// Heart image center
final heartData = [
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page.addPixelData(
ImageOptions(
data: heartData,
imageWidth: 16,
imageHeight: 11,
x: 200,
y: 80,
width: 50,
height: 35,
align: HAlignment.center,
vAlign: VAlignment.middle,
rotate: 30,
),
);
// Barcode bottom
page.addBarcode(
'123456789012',
const BarcodeOptions(
encoding: BarcodeEncoding.ean13,
x: 200,
y: 180,
width: 150,
height: 40,
align: HAlignment.center,
vAlign: VAlignment.middle,
),
);
page.addLine(
const LineOptions(x: 50, y: 220, endX: 350, endY: 220, thickness: 1));
await _showPreviewAndPrint(page, () async {
await _executePrintTask(page, 'Comprehensive demo printed');
});
}
void _showAlert(String title, String message) {
showDialog(
context: context,
builder: (context) => AlertDialog(
title: Text(title),
content: Text(message),
actions: [
TextButton(
onPressed: () => Navigator.pop(context),
child: const Text('OK'),
),
],
),
);
}
@override
Widget build(BuildContext context) {
return Stack(
children: [
Scaffold(
backgroundColor: const Color(0xFFF5FCFF),
body: SafeArea(
child: SingleChildScrollView(
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const SizedBox(height: 40),
const Text(
'NiimBlueLibRN',
style: TextStyle(
fontSize: 24,
fontWeight: FontWeight.bold,
color: Colors.red,
),
),
const SizedBox(height: 20),
Text(
'Status: $_status',
style: const TextStyle(fontSize: 16),
),
const SizedBox(height: 20),
_buildButton('π Connect to Printer', _handleConnect,
Colors.blue[700]!),
_buildButton(
'βοΈ Disconnect', _handleDisconnect, Colors.blue[700]!),
_buildButton('π¨οΈ Quick Print Test', _handlePrint,
Colors.blue[700]!),
_buildButton('π
°οΈ Bold Text Demo', _handlePrintBoldText,
Colors.blue[700]!),
_buildButton('π All-in-One Demo',
_handlePrintComprehensive, const Color(0xFF5856D6)),
_buildButton('π¨ Simple Demo', _handlePrintSimple,
const Color(0xFF34C759)),
_buildButton('π Landscape Mode', _handlePrintLandscape,
const Color(0xFF34C759)),
const SizedBox(height: 40),
],
),
),
),
),
),
if (_showDeviceList) _buildDeviceSelectionModal(),
if (_showPreview) _buildPreviewModal(),
],
);
}
Widget _buildButton(String label, VoidCallback onPressed, Color color) {
return Container(
width: MediaQuery.of(context).size.width * 0.8,
margin: const EdgeInsets.symmetric(vertical: 10),
child: ElevatedButton(
onPressed: onPressed,
style: ElevatedButton.styleFrom(
backgroundColor: color,
padding: const EdgeInsets.all(15),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(5),
),
),
child: Text(
label,
style: const TextStyle(
color: Colors.white,
fontSize: 16,
),
),
),
);
}
Widget _buildDeviceSelectionModal() {
return Container(
color: Colors.black.withValues(alpha: 0.5),
child: Center(
child: Container(
margin: const EdgeInsets.all(20),
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(10),
),
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
Padding(
padding: const EdgeInsets.all(20),
child: Text(
'Select a Device',
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
color: Colors.blue[700],
),
),
),
const Divider(height: 1),
ConstrainedBox(
constraints: BoxConstraints(
maxHeight: MediaQuery.of(context).size.height * 0.5,
),
child: Material(
color: Colors.transparent,
child: ListView.builder(
shrinkWrap: true,
itemCount: _devices.length,
itemBuilder: (context, index) {
final device = _devices[index];
final name = device.platformName;
final id = device.remoteId.str;
return ListTile(
title: Text(name),
subtitle: Text(id),
onTap: () => _connectToDevice(device),
);
},
),
),
),
const Divider(height: 1),
TextButton(
onPressed: () => setState(() => _showDeviceList = false),
child: const Text(
'Cancel',
style: TextStyle(color: Colors.red, fontSize: 16),
),
),
],
),
),
),
);
}
Widget _buildPreviewModal() {
return Material(
color: Colors.transparent,
child: Container(
color: Colors.black.withValues(alpha: 0.5),
child: Center(
child: Container(
margin: const EdgeInsets.all(20),
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(10),
),
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
Padding(
padding: const EdgeInsets.all(20),
child: Text(
'Preview',
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
color: Colors.blue[700],
),
),
),
const Divider(height: 1),
if (_previewImage != null)
Container(
color: Colors.black,
padding: const EdgeInsets.all(20),
child: Image.memory(
_previewImage!,
fit: BoxFit.contain,
height: MediaQuery.of(context).size.height * 0.4,
),
),
const Divider(height: 1),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
TextButton(
onPressed: () => setState(() => _showPreview = false),
child: const Text(
'Cancel',
style: TextStyle(color: Colors.red, fontSize: 16),
),
),
ElevatedButton(
onPressed: _executePrint,
style: ElevatedButton.styleFrom(
backgroundColor: const Color(0xFF34C759),
padding: const EdgeInsets.symmetric(
horizontal: 30,
vertical: 12,
),
),
child: const Text(
'Print',
style: TextStyle(color: Colors.white, fontSize: 16),
),
),
],
),
const SizedBox(height: 20),
],
),
),
),
),
);
}
@override
void dispose() {
_client?.disconnect();
super.dispose();
}
}Metadata
1
likes
150
points
174
downloads
Publisher
unverified uploader
Weekly Downloads
Metadata
Flutter library for BLE printing with NIIMBOT thermal printers. Supports 85+ printer models with automatic detection and rich content rendering.
Repository (GitHub)
View/report issues
Topics
#ble #printing #niimbot #thermal-printer #label-printer
Documentation
License
MIT (license)
Dependencies
barcode, crypto, flutter, flutter_blue_plus, http, image, qr, synchronized
