flutter_zsdk/example/lib/main.dart

import 'dart:developer';
import 'dart:math';

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

import 'package:flutter/services.dart';
import 'package:flutter_zsdk/flutter_zsdk.dart';
import 'package:flutter_zsdk/src/models/flutter_zsdk_exception.dart';
import 'package:flutter_zsdk_example/models/bluetooth_printer.dart';

void main() {
  runApp(const MaterialApp(home: MyApp()));
}

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

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final _formKey = GlobalKey<FormState>();

  bool _isDiscovering = false;
  List<BluetoothPrinter> _discoveredBluetoothPrinters = [];
  String? _connectedPrinter;
  final _flutterZsdkPlugin = FlutterZsdk();
  String? _selectedBluetoothPrinterMacAddress;
  bool _disconnecting = false;

  TextEditingController _zplDataController = TextEditingController();

  @override
  void initState() {
    super.initState();
    // initPlatformState();
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  // Future<void> initPlatformState() async {
  //   String platformVersion;
  //   // Platform messages may fail, so we use a try/catch PlatformException.
  //   // We also handle the message potentially returning null.
  //   try {
  //     platformVersion =
  //         await _flutterZsdkPlugin.getPlatformVersion() ?? 'Unknown platform version';
  //   } on PlatformException {
  //     platformVersion = 'Failed to get platform version.';
  //   }

  //   // If the widget was removed from the tree while the asynchronous platform
  //   // message was in flight, we want to discard the reply rather than calling
  //   // setState to update our non-existent appearance.
  //   if (!mounted) return;

  //   setState(() {
  //     _platformVersion = platformVersion;
  //   });
  // }

  StreamSubscription? _bluetoothPrinterSubscription;

  void showSnackBar(String message) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(message))
    );
  }

  Future<void> discoverBluetoothDevices() async {
    try {
      Stream<dynamic> stream = await _flutterZsdkPlugin.findBluetoothPrinters();
      _bluetoothPrinterSubscription = stream.listen((event) {
        print(event);

        if (event == 'SOS') {
          _isDiscovering = true;

        }

        if (event is List) {
          _discoveredBluetoothPrinters.clear();
          for (var printer in event) {
            BluetoothPrinter bluetoothPrinter = BluetoothPrinter.fromMap(printer);

            _discoveredBluetoothPrinters.add(bluetoothPrinter);
          }

        }

        if (event == 'EOS') {
          _isDiscovering = false;
          showSnackBar('Bluetooth discovery finished, found ${_discoveredBluetoothPrinters.length} printers');
          _bluetoothPrinterSubscription?.cancel();
        }

        setState(() {});
      });
    
    } on PlatformException catch (e) {
      inspect(e);
      showSnackBar(e.message.toString());

    } on FlutterZsdkException catch (e) { 
      inspect(e);
      showSnackBar(e.message);

    } catch (e) {
      inspect(e);
      showSnackBar('Unexpected error while discovering bluetooth printers');

    }
  }

  Future<void> openConnection() async {
    print('invoked openConnection from dart');
    try {
      await _flutterZsdkPlugin.openConnection(_selectedBluetoothPrinterMacAddress ?? ''); 
      _connectedPrinter = _selectedBluetoothPrinterMacAddress ?? 'Unknown printer';
      print('Connection opened successfully from dart');
      
    } on FlutterZsdkException catch (e) {
      inspect(e);
      showSnackBar(e.message);

    } catch (e) {
      inspect(e);
      showSnackBar('Unexpected error while connecting to bluetooth printers');
    }

    setState(() {});
  }

  Future<void> closeConnection() async {
    print('invoked closeConnection from dart');
    try {
      setState(() {
        _disconnecting = true;
      });
      await _flutterZsdkPlugin.closeConnection(); 
      _connectedPrinter = null;
      _disconnecting = false;
      print('Connection closed successfully from dart');
      
    } on FlutterZsdkException catch (e) {
      inspect(e);
      showSnackBar(e.message);

    } catch (e) {
      inspect(e);
      showSnackBar('Unexpected error while disconnecting bluetooth printers');
    }

    setState(() {});
  }

  Future<void> printZplOverBluetooth() async {
    if(!_formKey.currentState!.validate()) {
      return;
    }

    print('invoked printZplOverBluetooth from dart');
    try {
      await _flutterZsdkPlugin.printZplOverBluetooth(_zplDataController.text);
      print('printZplOverBluetooth successfully from dart');
      
    } on FlutterZsdkException catch (e) {
      inspect(e);
      showSnackBar(e.message);

    } catch (e) {
      inspect(e);
      showSnackBar('Unexpected error when send data to printers');
    }

    setState(() {});
  }

  Future<void> checkConnectionStatus() async {
    print('invoked checkConnectionStatus from dart');
    try{
      bool isConnected = await _flutterZsdkPlugin.isConnected();
              
      print('isConnected from dart: $isConnected');
    } on FlutterZsdkException catch (e) {
      inspect(e);
      showSnackBar(e.message.toString());
    } catch (e) {
      inspect(e);
      showSnackBar('Unexpected error while checking connection status');
    }
  }

  Future<void> calibrate() async {
    print('invoked calibrate from dart');
    try{
      await _flutterZsdkPlugin.calibrate();
              
    } on FlutterZsdkException catch (e) {
      inspect(e);
      showSnackBar(e.message.toString());
    } catch (e) {
      inspect(e);
      showSnackBar('Unexpected error while calibrating printer');
    }
  }

  Future<void> debugTest() async {
    print('invoked debugTest from dart');
    try{
      await _flutterZsdkPlugin.debugTest();
              
    } on FlutterZsdkException catch (e) {
      inspect(e);
      showSnackBar(e.message.toString());
    } catch (e) {
      inspect(e);
      showSnackBar('Unexpected error while checking connection status');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Plugin example app'),
      ),
      body: Form(
        key: _formKey,
        child: Center(
          child: SingleChildScrollView(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.center,
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Text('Connected printer: ${_connectedPrinter ?? "Unknown printer"}\n'),
                Text('Selected printer Mac Address: $_selectedBluetoothPrinterMacAddress\n'),
                SizedBox(height: 20),
            
                ElevatedButton(
                  child: Text('Connect to $_selectedBluetoothPrinterMacAddress'),
                  onPressed: _selectedBluetoothPrinterMacAddress == null ? null : openConnection,
                ),
                SizedBox(height: 20),
                    
                ElevatedButton(
                  child: Text(_disconnecting ? 'Disconnecting...' : 'Disconnect from $_connectedPrinter'),
                  onPressed: _connectedPrinter == null || _disconnecting ? null : closeConnection,
                ),
                SizedBox(height: 20),

                // debug button
                ElevatedButton(
                  child: Text('Debug'),
                  onPressed: debugTest
                ),
                SizedBox(height: 20),

                // calibrate button
                ElevatedButton(
                  child: Text('Calibrate'),
                  onPressed: _connectedPrinter == null || _disconnecting ? null : calibrate
                ),
                SizedBox(height: 20),
                
                TextFormField(
                  controller: _zplDataController,
                  decoration: InputDecoration(
                    hintText: 'Enter ZPL data here'
                  ),
                  validator: (value) {
                    if (value == null || value.isEmpty) {
                      return 'Please enter some text';
                    }
                    return null;
                  },
                ),
                    
                ElevatedButton(
                  child: Text('Print zpl over bluetooth'),
                  onPressed: _connectedPrinter == null ? null : printZplOverBluetooth,
                ),
                SizedBox(height: 20),
                    
                ElevatedButton(
                  child: Text('Check connection status'),
                  onPressed: checkConnectionStatus,
                ),
                SizedBox(height: 20),
                
                ElevatedButton(
                  child: Text(_isDiscovering ? 'Discovering bluetooth printers...' : 'Discover nearby bluetooth printers'),
                  onPressed: _isDiscovering ? null : () async {
                    discoverBluetoothDevices();
                  },
                ),
                SizedBox(height: 20),
                    
                for (var printer in _discoveredBluetoothPrinters) ... [
                  InkWell(
                    onTap: () {
                      _selectedBluetoothPrinterMacAddress = printer.macAddress;
                      setState(() {});
                    },
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Text(printer.friendlyName),
                        Text(printer.macAddress),
                        SizedBox(height: 10)
                      ],
                    ),
                  )
                ]
              ] 
              
            ),
          ),
        ),
      ),

    );
  }
}