flutter_print_label 0.2.0

flutter_print_label: ^0.2.0 copied to clipboard

example/lib/main.dart

import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter_print_label/flutter_print_label.dart';

void main() {
  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: 'flutter_print_label example',
      home: PrinterPage(),
    );
  }
}

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

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

class _PrinterPageState extends State<PrinterPage> {
  final _printer = FlutterPrintLabel.instance;

  final List<PrinterDevice> _devices = [];
  PrinterDevice? _selected;
  PrinterConnectionStatus _status = PrinterConnectionStatus.disconnected;
  bool _scanning = false;

  StreamSubscription<PrinterDevice>? _scanSub;
  StreamSubscription<PrinterConnectionStatus>? _statusSub;

  @override
  void initState() {
    super.initState();
    _statusSub = _printer.connectionStatus.listen((status) {
      setState(() => _status = status);
    });
    _scan();
  }

  @override
  void dispose() {
    _scanSub?.cancel();
    _statusSub?.cancel();
    super.dispose();
  }

  void _scan() {
    _scanSub?.cancel();
    setState(() {
      _devices.clear();
      _scanning = true;
    });

    // iOS always scans BLE. On Android a BLE scan also finds printers that
    // are not paired in system settings.
    _scanSub = _printer.scan(isBle: Platform.isIOS).listen(
      (device) {
        setState(() {
          final index = _devices.indexWhere((d) => d.address == device.address);
          if (index >= 0) {
            _devices[index] = device; // name update for the same device
          } else {
            _devices.add(device);
          }
        });
      },
      onDone: () => setState(() => _scanning = false),
    );
  }

  Future<void> _connect(PrinterDevice device) async {
    // Already connected to this device — nothing to do.
    if (_status == PrinterConnectionStatus.connected &&
        _printer.connectedDevice?.address == device.address) {
      return;
    }
    setState(() => _selected = device);
    await _printer.connect(device);
    // Wait for PrinterConnectionStatus.connected via the status stream.
  }

  Future<void> _printTestLabel() async {
    // A complete 100 x 150 mm (800 x 1200 dots @ 203 dpi) TSPL test label:
    // title, printer info, Code 128 barcode, divider lines, label specs,
    // footer, and a QR code — matching the sample image shipped with the
    // package (image/sample_label.png).
    await _printer.printTspl(
      'SIZE 100 mm,150 mm\r\n'
      'GAP 3 mm,0 mm\r\n'
      'DIRECTION 1\r\n'
      'CLS\r\n'
      // --- Header ---
      'TEXT 50,80,"3",0,2,2,"FLUTTER PRINT LABEL"\r\n'
      'TEXT 50,195,"3",0,1,1,"Printer: ${_selected?.name ?? "-"}"\r\n'
      'TEXT 50,255,"3",0,1,1,"Test print OK"\r\n'
      // --- Code 128 barcode, 200 dots tall, human-readable below ---
      'BARCODE 50,340,"128",200,2,0,3,3,"TEST1234"\r\n'
      // --- Divider line (BAR x,y,width,height) ---
      'BAR 50,640,700,3\r\n'
      // --- Label specs ---
      'TEXT 50,675,"3",0,1,1,"SIZE : 100 x 150 mm"\r\n'
      'TEXT 50,725,"3",0,1,1,"GAP  : 3 mm"\r\n'
      'TEXT 50,775,"3",0,1,1,"MODE : TSPL over Bluetooth (BLE)"\r\n'
      // --- Divider line ---
      'BAR 50,850,700,3\r\n'
      // --- Footer ---
      'TEXT 50,885,"3",0,1,1,"Printed with flutter_print_label"\r\n'
      'TEXT 50,940,"2",0,1,1,"pub.dev/packages/flutter_print_label"\r\n'
      // --- QR code, bottom right (cell size 7 ~= 200 dots wide) ---
      'QRCODE 540,960,M,7,A,0,"https://pub.dev/packages/flutter_print_label"\r\n'
      'PRINT 1,1\r\n',
    );

    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(content: Text('Test label sent')),
    );
  }

  @override
  Widget build(BuildContext context) {
    final connected = _status == PrinterConnectionStatus.connected;

    return Scaffold(
      appBar: AppBar(
        title: const Text('flutter_print_label'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            tooltip: 'Rescan',
            onPressed: _scan,
          ),
        ],
      ),
      body: Column(
        children: [
          ListTile(
            leading: Icon(
              connected ? Icons.bluetooth_connected : Icons.bluetooth_disabled,
              color: connected ? Colors.green : Colors.grey,
            ),
            title: Text('Status: ${_status.name}'),
            subtitle: _selected == null ? null : Text(_selected!.name),
            trailing: ElevatedButton(
              onPressed: connected ? _printTestLabel : null,
              child: const Text('Print test label'),
            ),
          ),
          const Divider(height: 1),
          Expanded(
            child: _devices.isEmpty
                ? Center(
                    child: Text(
                      _scanning
                          ? 'Scanning for printers...'
                          : 'No printers found.\n'
                              'Power-cycle the printer and rescan.',
                      textAlign: TextAlign.center,
                    ),
                  )
                : ListView.builder(
                    itemCount: _devices.length,
                    itemBuilder: (context, index) {
                      final device = _devices[index];
                      // The connected device is injected into scan results by
                      // the plugin (it stops advertising while connected).
                      final isConnectedDevice = connected &&
                          _printer.connectedDevice?.address == device.address;
                      return ListTile(
                        leading: const Icon(Icons.print),
                        title: Text(device.name),
                        subtitle: Text(device.address),
                        trailing: isConnectedDevice
                            ? const Icon(Icons.check_circle,
                                color: Colors.green)
                            : null,
                        onTap: () => _connect(device),
                      );
                    },
                  ),
          ),
          if (connected)
            const Padding(
              padding: EdgeInsets.all(12),
              child: Text(
                'Tip: a connected printer stops advertising, '
                'so it will not appear in new scan results.',
                style: TextStyle(fontSize: 12, color: Colors.grey),
              ),
            ),
        ],
      ),
    );
  }
}