آموزش اتصال اپلیکیشن فلاتر به پرینتر بلوتوثی

<!-- Request legacy Bluetooth permissions on older devices. -->
<uses-permission android:name="android.permission.BLUETOOTH"
                 android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"
                 android:maxSdkVersion="30" />

<!-- Needed only if your app looks for Bluetooth devices.
     If your app doesn't use Bluetooth scan results to derive physical
     location information, you can strongly assert that your app
     doesn't derive physical location. -->
<uses-permission android:name="android.permission.BLUETOOTH_SCAN" />

<!-- Needed only if your app communicates with already-paired Bluetooth
     devices. -->
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

<!-- Needed only if your app uses Bluetooth scan results to derive physical location. -->  
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

<key>NSBluetoothAlwaysUsageDescription</key>  
<string>Need BLE permission</string>  
<key>NSBluetoothPeripheralUsageDescription</key>  
<string>Need BLE permission</string>  
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>  
<string>Need Location permission</string>  
<key>NSLocationAlwaysUsageDescription</key>  
<string>Need Location permission</string>  
<key>NSLocationWhenInUseUsageDescription</key>  
<string>Need Location permission</string>

import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';

import 'package:blue_print_pos/blue_print_pos.dart';
import 'package:blue_print_pos/models/blue_device.dart';
import 'package:blue_print_pos/models/connection_status.dart';
import 'package:blue_print_pos/receipt/receipt_section_text.dart';
import 'package:blue_print_pos/receipt/receipt_text_size_type.dart';
import 'package:blue_print_pos/receipt/receipt_text_style_type.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:permission_handler/permission_handler.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Bluetooth Print Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Bluetooth Print Demo'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final BluePrintPos _bluePrintPos = BluePrintPos.instance;
  List<BlueDevice> _blueDevices = <BlueDevice>[];
  BlueDevice? _selectedDevice;
  bool _isLoading = false;
  int _loadingAtIndex = -1;

  Future<void> _onScanPressed() async {
    if (Platform.isAndroid) {
      Map<Permission, PermissionStatus> statuses = await [
        Permission.bluetoothScan,
        Permission.bluetoothConnect,
      ].request();
      if (statuses[Permission.bluetoothScan] != PermissionStatus.granted ||
          statuses[Permission.bluetoothConnect] != PermissionStatus.granted) {
        return;
      }
    }

    setState(() => _isLoading = true);
    _bluePrintPos.scan().then((List<BlueDevice> devices) {
      if (devices.isNotEmpty) {
        setState(() {
          _blueDevices = devices;
          _isLoading = false;
        });
      } else {
        setState(() => _isLoading = false);
      }
    });
  }

  void _onDisconnectDevice() {
    _bluePrintPos.disconnect().then((ConnectionStatus status) {
      if (status == ConnectionStatus.disconnect) {
        setState(() {
          _selectedDevice = null;
        });
      }
    });
  }

  void _onSelectDevice(int index) {
    setState(() {
      _isLoading = true;
      _loadingAtIndex = index;
    });
    final BlueDevice blueDevice = _blueDevices[index];
    _bluePrintPos.connect(blueDevice).then((ConnectionStatus status) {
      if (status == ConnectionStatus.connected) {
        setState(() => _selectedDevice = blueDevice);
      } else if (status == ConnectionStatus.timeout) {
        _onDisconnectDevice();
      } else {
        if (kDebugMode) {
          print('$runtimeType - something wrong');
        }
      }
      setState(() => _isLoading = false);
    });
  }

  Future<void> _onPrintReceipt() async {
    /// Example for Print Image
    final ByteData logoBytes = await rootBundle.load(
      'assets/logo.jpg',
    );

    /// Example for Print Text
    final ReceiptSectionText receiptText = ReceiptSectionText();
    receiptText.addImage(
      base64.encode(Uint8List.view(logoBytes.buffer)),
      width: 300,
    );
    receiptText.addSpacer();
    receiptText.addText(
      'EXCEED YOUR VISION',
      size: ReceiptTextSizeType.medium,
      style: ReceiptTextStyleType.bold,
    );
    receiptText.addText(
      'MC Koo',
      size: ReceiptTextSizeType.small,
    );
    receiptText.addSpacer(useDashed: true);
    receiptText.addLeftRightText('Time', '04/06/22, 10:30');
    receiptText.addSpacer(useDashed: true);
    receiptText.addLeftRightText(
      'Apple 4pcs',
      '\$ 10.00',
      leftStyle: ReceiptTextStyleType.normal,
      rightStyle: ReceiptTextStyleType.bold,
    );
    receiptText.addSpacer(useDashed: true);
    receiptText.addLeftRightText(
      'TOTAL',
      '\$ 10.00',
      leftStyle: ReceiptTextStyleType.normal,
      rightStyle: ReceiptTextStyleType.bold,
    );
    receiptText.addSpacer(useDashed: true);
    receiptText.addLeftRightText(
      'Payment',
      'Cash',
      leftStyle: ReceiptTextStyleType.normal,
      rightStyle: ReceiptTextStyleType.normal,
    );
    receiptText.addSpacer(count: 2);

    await _bluePrintPos.printReceiptText(receiptText);

    /// Example for print QR
    await _bluePrintPos.printQR('https://www.google.com/', size: 250);

    /// Text after QR
    final ReceiptSectionText receiptSecondText = ReceiptSectionText();
    receiptSecondText.addText('Powered by Google',
        size: ReceiptTextSizeType.small);
    receiptSecondText.addSpacer();
    await _bluePrintPos.printReceiptText(receiptSecondText, feedCount: 1);
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: SafeArea(
        child: _isLoading && _blueDevices.isEmpty
            ? const Center(
                child: CircularProgressIndicator(
                  valueColor: AlwaysStoppedAnimation<Color>(Colors.blue),
                ),
              )
            : _blueDevices.isNotEmpty
                ? SingleChildScrollView(
                    padding: const EdgeInsets.all(16),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: <Widget>[
                        Column(
                          children: List<Widget>.generate(_blueDevices.length,
                              (int index) {
                            return Row(
                              children: <Widget>[
                                Expanded(
                                  child: GestureDetector(
                                    onTap: _blueDevices[index].address ==
                                            (_selectedDevice?.address ?? '')
                                        ? _onDisconnectDevice
                                        : () => _onSelectDevice(index),
                                    child: Padding(
                                      padding: const EdgeInsets.all(8.0),
                                      child: Column(
                                        crossAxisAlignment:
                                            CrossAxisAlignment.start,
                                        children: <Widget>[
                                          Text(
                                            _blueDevices[index].name,
                                            style: TextStyle(
                                              color: _selectedDevice?.address ==
                                                      _blueDevices[index]
                                                          .address
                                                  ? Colors.blue
                                                  : Colors.black,
                                              fontSize: 20,
                                              fontWeight: FontWeight.w500,
                                            ),
                                          ),
                                          Text(
                                            _blueDevices[index].address,
                                            style: TextStyle(
                                              color: _selectedDevice?.address ==
                                                      _blueDevices[index]
                                                          .address
                                                  ? Colors.blueGrey
                                                  : Colors.grey,
                                              fontSize: 14,
                                              fontWeight: FontWeight.w500,
                                            ),
                                          ),
                                        ],
                                      ),
                                    ),
                                  ),
                                ),
                                if (_loadingAtIndex == index && _isLoading)
                                  Container(
                                    height: 24.0,
                                    width: 24.0,
                                    margin: const EdgeInsets.only(right: 8.0),
                                    child: const CircularProgressIndicator(
                                      valueColor: AlwaysStoppedAnimation<Color>(
                                        Colors.blue,
                                      ),
                                    ),
                                  ),
                                if (!_isLoading &&
                                    _blueDevices[index].address ==
                                        (_selectedDevice?.address ?? ''))
                                  TextButton(
                                    onPressed: _onPrintReceipt,
                                    child: Container(
                                      color: _selectedDevice == null
                                          ? Colors.grey
                                          : Colors.blue,
                                      padding: const EdgeInsets.all(8.0),
                                      child: const Text(
                                        'Test Print',
                                        style: TextStyle(color: Colors.white),
                                      ),
                                    ),
                                    style: ButtonStyle(
                                      backgroundColor: MaterialStateProperty
                                          .resolveWith<Color>(
                                        (Set<MaterialState> states) {
                                          if (states.contains(
                                              MaterialState.pressed)) {
                                            return Theme.of(context)
                                                .colorScheme
                                                .primary
                                                .withOpacity(0.5);
                                          }
                                          return Theme.of(context).primaryColor;
                                        },
                                      ),
                                    ),
                                  ),
                              ],
                            );
                          }),
                        ),
                      ],
                    ),
                  )
                : Center(
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: const <Widget>[
                        Text(
                          'Scan bluetooth device',
                          style: TextStyle(fontSize: 24, color: Colors.blue),
                        ),
                        Text(
                          'Press button scan',
                          style: TextStyle(fontSize: 14, color: Colors.grey),
                        ),
                      ],
                    ),
                  ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _isLoading ? null : _onScanPressed,
        child: const Icon(Icons.search),
        backgroundColor: _isLoading ? Colors.grey : Colors.blue,
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}