I can't print (Knup 1022)

[JunioJsv]

Is something wrong with my code? I am trying to print using this function and an error is occurring, leave the logcat below.

void connectDevice(BuildContext context,
      {void Function(BluetoothPrint) connected}) {
    _bluetooth.state.listen((state) {
      if (state == BluetoothPrint.CONNECTED) {
        _bluetooth.printReceipt(Map(), [
          LineText(
              type: LineText.TYPE_TEXT,
              size: 12,
              content: 'Ola mundo',
              align: LineText.ALIGN_CENTER,
              linefeed: 1)
        ]);
      }
    });
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (_) {
        return AlertDialog(
          title: Text('Encontar dispositivos'),
          content: StreamBuilder<bool>(
            key: UniqueKey(),
            initialData: false,
            stream: _bluetooth.isScanning,
            builder: (_, status) {
              return Column(
                mainAxisSize: MainAxisSize.max,
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: <Widget>[
                  StreamBuilder<List<BluetoothDevice>>(
                    key: UniqueKey(),
                    initialData: [],
                    stream: _bluetooth.scanResults,
                    builder: (_, results) {
                      return results.data.length == 0 && status.data
                          ? Expanded(
                              child: Center(
                                child: CircularProgressIndicator(),
                              ),
                            )
                          : ListView(
                              key: UniqueKey(),
                              shrinkWrap: true,
                              children: results.data
                                  .map(
                                    (device) => ListTile(
                                      key: UniqueKey(),
                                      enabled: status.data ? false : true,
                                      title: Text('${device.name}'),
                                      subtitle: Text('${device.address}'),
                                      onTap: () {
                                        _bluetooth.connect(device);
                                      },
                                    ),
                                  )
                                  .toList(),
                            );
                    },
                  ),
                  FlatButton(
                    onPressed: () => status.data
                        ? _bluetooth.stopScan()
                        : _bluetooth.startScan(),
                    child: Text(status.data
                        ? 'ENCERRAR BUSCA'
                        : 'BUSCAR DISPOSITIOVOS'),
                  )
                ],
              );
            },
          ),
        );
      },
    );
  }

2020-01-17 16:54:30.657 24773-24925/juniojsv.bem_servir_comanda W/BluetoothAdapter: getBluetoothService() called with no BluetoothManagerCallback
2020-01-17 16:54:33.617 24773-24773/juniojsv.bem_servir_comanda D/BluetoothPrintPlugin: stateStreamHandler, current action: android.bluetooth.device.action.ACL_CONNECTED
2020-01-17 16:54:33.632 24773-24789/juniojsv.bem_servir_comanda E/flutter: [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: PlatformException(not connect, state not right, null)
    #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
    #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:156:18)
    <asynchronous suspension>
    #2      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)
    #3      BluetoothPrint.printReceipt (package:bluetooth_print/bluetooth_print.dart:141:14)
    #4      AppModel.connectDevice.<anonymous closure> (package:bem_servir_comanda/models/app_model.dart:20:20)
    #5      _rootRunUnary (dart:async/zone.dart:1134:38)
    #6      _CustomZone.runUnary (dart:async/zone.dart:1031:19)
    #7      _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
    #8      _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
    #9      _DelayedData.perform (dart:async/stream_impl.dart:594:14)
    #10     _StreamImplEvents.handleNext (dart:async/stream_impl.dart:710:11)
    #11     _PendingEvents.schedule.<anonymous closure> (dart:async/stream_impl.dart:670:7)
    #12     _rootRun (dart:async/zone.dart:1122:38)
    #13     _CustomZone.run (dart:async/zone.dart:1023:19)
    #14     _CustomZone.runGuarded (dart:async/zone.dart:925:7)
    #15     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:965:23)
    #16     _rootRun (dart:async/zone.dart:1126:13)
    #17     _CustomZone.run (dart:async/zone.dart:1023:19)
    #18     _CustomZone.runGuarded (dart:async/zone.dart:925:7)
    #19     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:965:23)
    #20     _microtaskLoop (dart:async/schedule_microtask.dart:43:21)
    #21     _startMicrotaskLoop (dart:async/schedule_microtask.dart:52:5)
2020-01-17 16:54:33.820 24773-24960/juniojsv.bem_servir_comanda E/DeviceConnFactoryManager: wait read 
2020-01-17 16:54:35.573 24773-24960/juniojsv.bem_servir_comanda E/BluetoothPort: read length1
2020-01-17 16:54:35.573 24773-24960/juniojsv.bem_servir_comanda E/DeviceConnFactoryManager:  read 1
2020-01-17 16:54:35.575 24773-24960/juniojsv.bem_servir_comanda E/DeviceConnFactoryManager: wait read 

[thon-ju]

@JunioJsv please gei me your device type, and anroid version, i'll have a try

[NivethaMuthukumar]

Device modal: tsc alpha-3r bluetooth printer => printing not work

[lyseiha]

@JunioJsv please gei me your device type, and anroid version, i'll have a try

it is working on xprinter xp-420b?