android - Flutter Blue无法检测到蓝牙打印机(Zebra ez320)

Question

您好，我尝试打印到蓝牙打印机中，但是示例代码中的第一个问题是它没有检测到任何蓝牙设备，并且显示了我不知道该设备是什么的设备列表，我尝试了所有方法使其正常工作，但是没发生什么事。顺便说一句，我正在使用名为https://pub.dev/packages/esc_pos_printer的软件包

这是搜索后的结果

import 'package:flutter/services.dart';
import 'package:image/image.dart';
import 'package:esc_pos_printer/esc_pos_printer.dart';
import 'package:flutter/material.dart' hide Image;
import 'package:oktoast/oktoast.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return OKToast(
      child: MaterialApp(
        title: 'Bluetooth demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: MyHomePage(title: 'Bluetooth demo'),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  PrinterBluetoothManager printerManager = PrinterBluetoothManager();
  List<PrinterBluetooth> _devices = [];

  @override
  void initState() {
    super.initState();

    printerManager.scanResults.listen((devices) async {
       print('UI: Devices found ${devices.length}');
      setState(() {
        _devices = devices;
      });
    });
  }

  void _startScanDevices() async{

    setState(() {
      _devices = [];
    });
    printerManager.startScan(Duration(seconds: 100));
  }

  void _stopScanDevices() {
    printerManager.stopScan();
  }

  Future<Ticket> testTicket() async {
    final Ticket ticket = Ticket(PaperSize.mm58);
    ticket.text(
        'Regular: aA bB cC dD eE fF gG hH iI jJ kK lL mM nN oO pP qQ rR sS tT uU vV wW xX yY zZ');
    ticket.text('Special 1: àÀ èÈ éÉ ûÛ üÜ çÇ ôÔ',
        styles: PosStyles(codeTable: PosCodeTable.westEur));
    ticket.text('Special 2: blåbærgrød',
        styles: PosStyles(codeTable: PosCodeTable.westEur));

    ticket.text('Bold text', styles: PosStyles(bold: true));
    ticket.text('Reverse text', styles: PosStyles(reverse: true));
    ticket.text('Underlined text',
        styles: PosStyles(underline: true), linesAfter: 1);
    ticket.text('Align left', styles: PosStyles(align: PosTextAlign.left));
    ticket.text('Align center', styles: PosStyles(align: PosTextAlign.center));
    ticket.text('Align right',
        styles: PosStyles(align: PosTextAlign.right), linesAfter: 1);

    ticket.row([
      PosColumn(
        text: 'col3',
        width: 3,
        styles: PosStyles(align: PosTextAlign.center, underline: true),
      ),
      PosColumn(
        text: 'col6',
        width: 6,
        styles: PosStyles(align: PosTextAlign.center, underline: true),
      ),
      PosColumn(
        text: 'col3',
        width: 3,
        styles: PosStyles(align: PosTextAlign.center, underline: true),
      ),
    ]);

    ticket.text('Text size 200%',
        styles: PosStyles(
          height: PosTextSize.size2,
          width: PosTextSize.size2,
        ));

    // Print image
    final ByteData data = await rootBundle.load('assets/logo.png');
    final Uint8List bytes = data.buffer.asUint8List();
    final Image image = decodeImage(bytes);
    ticket.image(image);
    // Print image using an alternative (obsolette) command
    // ticket.imageRaster(image);

    // Print barcode
    final List<int> barData = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 4];
    ticket.barcode(Barcode.upcA(barData));

    // Print mixed (chinese + latin) text. Only for printers supporting Kanji mode
    // ticket.text(
    //   'hello ! 中文字 # world @ éphémère &',
    //   styles: PosStyles(codeTable: PosCodeTable.westEur),
    //   containsChinese: true,
    // );

    ticket.feed(2);
    return ticket;
  }

  void _testPrint(PrinterBluetooth printer) async {
    printerManager.selectPrinter(printer);

    final PosPrintResult res =
    await printerManager.printTicket(await testTicket());
    showToast(res.msg);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: ListView.builder(
          itemCount: _devices.length,
          itemBuilder: (BuildContext context, int index) {
            return InkWell(
              onTap: () => _testPrint(_devices[index]),
              child: Column(
                children: <Widget>[
                  Container(
                    height: 60,
                    padding: EdgeInsets.only(left: 10),
                    alignment: Alignment.centerLeft,
                    child: Row(
                      children: <Widget>[
                        Icon(Icons.print),
                        SizedBox(width: 10),
                        Expanded(
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            mainAxisAlignment: MainAxisAlignment.center,
                            children: <Widget>[
                              Text(_devices[index].name ?? ''),
                              Text(_devices[index].address),
                              Text(
                                'Click to print a test receipt',
                                style: TextStyle(color: Colors.grey[700]),
                              ),
                            ],
                          ),
                        )
                      ],
                    ),
                  ),
                  Divider(),
                ],
              ),
            );
          }),
      floatingActionButton: StreamBuilder<bool>(
        stream: printerManager.isScanningStream,
        initialData: false,
        builder: (c, snapshot) {
          if (snapshot.data) {
            return FloatingActionButton(
              child: Icon(Icons.stop),
              onPressed: _stopScanDevices,
              backgroundColor: Colors.red,
            );
          } else {
            return FloatingActionButton(
              child: Icon(Icons.search),
              onPressed: _startScanDevices,
            );
          }
        },
      ),
    );
  }
}

Answer 1

似乎Zebra ez320不是ESC / POS打印机，而该库旨在与ESC / POS打印机通信。