Bluetooth Low Energy (BLE) とBluetooth Classicの違い

// MainActivity.java
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugins.GeneratedPluginRegistrant;
import io.flutter.app.FlutterActivity;

public class MainActivity extends FlutterActivity {
  private static final String CHANNEL = "bluetooth_channel";
  private BluetoothAdapter bluetoothAdapter;
  private MethodChannel.Result scanResult;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    GeneratedPluginRegistrant.registerWith(this);

    new MethodChannel(getFlutterView(), CHANNEL).setMethodCallHandler(
      new MethodCallHandler() {
        @Override
        public void onMethodCall(MethodCall call, Result result) {
          if (call.method.equals("startScan")) {
            startScan(result);
          } else {
            result.notImplemented();
          }
        }
      }
    );

    bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
    registerReceiver(receiver, filter);
  }

  private void startScan(MethodChannel.Result result) {
    scanResult = result;
    bluetoothAdapter.startDiscovery();
  }

  private final BroadcastReceiver receiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();
      if (BluetoothDevice.ACTION_FOUND.equals(action)) {
        BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
        String deviceName = device.getName();
        String deviceAddress = device.getAddress();
        scanResult.success(deviceName + " - " + deviceAddress);
      }
    }
  };

  @Override
  protected void onDestroy() {
    super.onDestroy();
    unregisterReceiver(receiver);
  }
}

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: BluetoothClassicScreen(),
    );
  }
}

class BluetoothClassicScreen extends StatefulWidget {
  @override
  _BluetoothClassicScreenState createState() => _BluetoothClassicScreenState();
}

class _BluetoothClassicScreenState extends State<BluetoothClassicScreen> {
  static const platform = MethodChannel('bluetooth_channel');
  String _deviceInfo = 'No device found';

  void _startScan() async {
    try {
      final String result = await platform.invokeMethod('startScan');
      setState(() {
        _deviceInfo = result;
      });
    } on PlatformException catch (e) {
      setState(() {
        _deviceInfo = "Failed to start scan: '${e.message}'.";
      });
    }
  }

  @override
  Widget build(BuildContextContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Bluetooth Classic Scanner'),
      ),
      body: Center(
        child: Text(_deviceInfo),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _startScan,
        child: Icon(Icons.search),
      ),
    );
  }
}