### Main Application Setup

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.9.0/example

Initializes the Flutter application and requests necessary Bluetooth and location permissions on Android. It then starts the main app widget.

```dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';
import 'package:permission_handler/permission_handler.dart';

import 'widgets.dart';

void main() {
  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [ 
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
    runApp(const FlutterBlueApp());
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothAdapterState>(
          stream: FlutterBluePlus.instance.adapterState,
          initialData: BluetoothAdapterState.unknown,
          builder: (c, snapshot) {
            final adapterState = snapshot.data;
            if (adapterState == BluetoothAdapterState.on) {
              return const FindDevicesScreen();
            }
            return BluetoothOffScreen(adapterState: adapterState);
          }),
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.adapterState}) : super(key: key);

  final BluetoothAdapterState? adapterState;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.lightBlue,
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            const Icon(
              Icons.bluetooth_disabled,
              size: 200.0,
              color: Colors.white54,
            ),
            Text(
              'Bluetooth Adapter is ${adapterState != null ? adapterState.toString().substring(15) : 'not available'}.',
              style: Theme.of(context)
                  .primaryTextTheme
                  .titleSmall
                  ?.copyWith(color: Colors.white),
            ),
            ElevatedButton(
              child: const Text('TURN ON'),
              onPressed: Platform.isAndroid
                  ? () => FlutterBluePlus.instance.turnOn()
                  : null,
            ),
          ],
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Find Devices'),
        actions: [
          ElevatedButton(
            child: const Text('TURN OFF'),
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.black,
              foregroundColor: Colors.white,
            ),
            onPressed: Platform.isAndroid
                ? () => FlutterBluePlus.instance.turnOff()
                : null,
          ),
        ],
      ),
      body: RefreshIndicator(
        onRefresh: () => FlutterBluePlus.instance.startScan(
            timeout: const Duration(seconds: 4),
            androidUsesFineLocation:
                false), // if set to true add permission ACCESS_FINE_LOCATION to AndroidManifest.xml
        child: SingleChildScrollView(
          child: Column(
            children: <Widget>[
              StreamBuilder<List<BluetoothDevice>>(
                stream: Stream.periodic(const Duration(seconds: 2))
                    .asyncMap((_) => FlutterBluePlus.instance.connectedDevices),
                initialData: const [],
                builder: (c, snapshot) => Column(
                  children: snapshot.data!
                      .map((d) => ListTile(
                            title: Text(d.localName),
                            subtitle: Text(d.remoteId.toString()),
                            trailing: StreamBuilder<BluetoothConnectionState>(
                              stream: d.connectionState,
                              initialData: BluetoothConnectionState.disconnected,
                              builder: (c, snapshot) {
                                if (snapshot.data ==
                                    BluetoothConnectionState.connected) {
                                  return ElevatedButton(
                                    child: const Text('OPEN'),
                                    onPressed: () => Navigator.of(context).push(
                                        MaterialPageRoute(

```

--------------------------------

### Main Application Setup

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.7.1/example

Initializes the Flutter application, requests necessary Bluetooth and location permissions on Android, and starts the main app widget. Handles Bluetooth state changes to display the appropriate UI.

```dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';
import 'package:permission_handler/permission_handler.dart';

import 'widgets.dart';

void main() {

  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
      runApp(const FlutterBlueApp());
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothState>(
          stream: FlutterBluePlus.instance.state,
          initialData: BluetoothState.unknown,
          builder: (c, snapshot) {
            final state = snapshot.data;
            if (state == BluetoothState.on) {
              return const FindDevicesScreen();
            }
            return BluetoothOffScreen(state: state);
          }),
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.state}) : super(key: key);

  final BluetoothState? state;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.lightBlue,
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            const Icon(
              Icons.bluetooth_disabled,
              size: 200.0,
              color: Colors.white54,
            ),
            Text(
              'Bluetooth Adapter is ${state != null ? state.toString().substring(15) : 'not available'}.',
              style: Theme.of(context)
                  .primaryTextTheme
                  .subtitle2
                  ?.copyWith(color: Colors.white),
            ),
            ElevatedButton(
              child: const Text('TURN ON'),
              onPressed: Platform.isAndroid
                  ? () => FlutterBluePlus.instance.turnOn()
                  : null,
            ),
          ],
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Find Devices'),
        actions: [
          ElevatedButton(
            child: const Text('TURN OFF'),
            style: ElevatedButton.styleFrom(
              primary: Colors.black,
              onPrimary: Colors.white,
            ),
            onPressed: Platform.isAndroid
                ? () => FlutterBluePlus.instance.turnOff()
                : null,
          ),
        ],
      ),
      body: RefreshIndicator(
        onRefresh: () => FlutterBluePlus.instance
            .startScan(timeout: const Duration(seconds: 4)),
        child: SingleChildScrollView(
          child: Column(
            children: <Widget>[
              StreamBuilder<List<BluetoothDevice>>(
                stream: Stream.periodic(const Duration(seconds: 2))
                    .asyncMap((_) => FlutterBluePlus.instance.connectedDevices),
                initialData: const [],
                builder: (c, snapshot) => Column(
                  children: snapshot.data!
                      .map((d) => ListTile(
                            title: Text(d.name),
                            subtitle: Text(d.id.toString()),
                            trailing: StreamBuilder<BluetoothDeviceState>(
                              stream: d.state,
                              initialData: BluetoothDeviceState.disconnected,
                              builder: (c, snapshot) {
                                if (snapshot.data ==
                                    BluetoothDeviceState.connected) {
                                  return ElevatedButton(
                                    child: const Text('OPEN'),
                                    onPressed: () => Navigator.of(context).push(
                                        MaterialPageRoute(
                                            builder: (context) =>
                                                DeviceScreen(device: d))),
                                  );
                                }
                                return Text(snapshot.data.toString());
                              }
                            ),
                          ))
                      .toList(),
                ),
              )
            ],
          ),
        ),
      ),
    );
  }
}

class DeviceScreen extends StatelessWidget {
  const DeviceScreen({Key? key, required this.device}) : super(key: key);

  final BluetoothDevice device;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(device.name),
        actions: [
          StreamBuilder<BluetoothDeviceState>(
            stream: device.state,
            initialData: BluetoothDeviceState.connecting,
            builder: (c, snapshot) => (
                snapshot.data == BluetoothDeviceState.connected
                    ? {
                        TextButton(
                          child: const Text('NORMAL'),
                          onPressed: () => null, // TODO: implement
                        ),
                        TextButton(
                          child: const Text('FULL'),
                          onPressed: () => null, // TODO: implement
                        )
                      }
                    : const <Widget>[])
                .firstOrNull ??
                const Text(''),
          )
        ],
      ),
      body: ListView(
        children:
          <Widget>[
            StreamBuilder<BluetoothDeviceState>(
              stream: device.state,
              initialData: BluetoothDeviceState.connecting,
              builder: (c, snapshot) => ListBody(
                children: [
                  ListTile(title: const Text('Device is'), subtitle: Text(snapshot.data.toString()), leading: const Icon(Icons.bluetooth_audio),),
                  ListTile(title: const Text('Name'), subtitle: Text(device.name), leading: const Icon(Icons.bookmark_border),),
                  ListTile(title: const Text('ID'), subtitle: Text(device.id.toString()), leading: const Icon(Icons.info_outline),),
                  ListTile(title: const Text('System MTU'), subtitle: Text('${device.mtu.oops}'), leading: const Icon(Icons.branding_watermark),),
                  // TODO: Add connection state
                  // StreamBuilder<bool>(stream: device.isDiscoveringServices, initialData: false, builder: (c, snapshot) => ListTile(title: Text('Discovering Services...'), subtitle: Text(snapshot.data.toString()),),),
                  // DeviceProvider(device: device, child: const ServicesList()),
                ],
              ),
            )
          ]
            ..addAll(
              [
                // TODO: Add connection state
                // StreamBuilder<bool>(stream: device.isDiscoveringServices, initialData: false, builder: (c, snapshot) => ListTile(title: Text('Discovering Services...'), subtitle: Text(snapshot.data.toString()),),),
                // DeviceProvider(device: device, child: const ServicesList()),
              ]
            ),
      ),
    );
  }

  // TODO: Add connection state
  // Widget _buildConnectButton(BuildContext context, BluetoothDeviceState state) {
  //   // ...
  // }
}

// TODO: Add connection state
// class ServicesList extends StatelessWidget {
//   // ...
// }

// TODO: Add connection state
// class DeviceProvider extends InheritedWidget {
//   // ...
// }

```

--------------------------------

### Main Application Setup

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.14.10/example

Initializes the Flutter application, requests necessary Bluetooth and location permissions on Android, and starts the main app widget. Handles platform-specific initialization.

```dart
// Copyright 2023, Charles Weinberger & Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

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

import 'widgets.dart';

final snackBarKeyA = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyB = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyC = GlobalKey<ScaffoldMessengerState>();
final Map<DeviceIdentifier, ValueNotifier<bool>> isConnectingOrDisconnecting = {};

void main() {
  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [ 
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
    runApp(const FlutterBlueApp());
  }
}

class BluetoothAdapterStateObserver extends NavigatorObserver {
  StreamSubscription<BluetoothAdapterState>? _btStateSubscription;

  @override
  void didPush(Route route, Route? previousRoute) {
    super.didPush(route, previousRoute);
    if (route.settings.name == '/deviceScreen') {
      // Start listening to Bluetooth state changes when a new route is pushed
      _btStateSubscription ??= FlutterBluePlus.adapterState.listen((state) {
        if (state != BluetoothAdapterState.on) {
          // Pop the current route if Bluetooth is off
          navigator?.pop();
        }
      });
    }
  }

  @override
  void didPop(Route route, Route? previousRoute) {
    super.didPop(route, previousRoute);
    // Cancel the subscription when the route is popped
    _btStateSubscription?.cancel();
    _btStateSubscription = null;
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothAdapterState>(
          stream: FlutterBluePlus.adapterState,
          initialData: BluetoothAdapterState.unknown,
          builder: (c, snapshot) {
            final adapterState = snapshot.data;
            if (adapterState == BluetoothAdapterState.on) {
              return const FindDevicesScreen();
            } else {
              FlutterBluePlus.stopScan();
              return BluetoothOffScreen(adapterState: adapterState);
            }
          }),
      navigatorObservers: [BluetoothAdapterStateObserver()],
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.adapterState}) : super(key: key);

  final BluetoothAdapterState? adapterState;

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyA,
      child: Scaffold(
        backgroundColor: Colors.lightBlue,
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              const Icon(
                Icons.bluetooth_disabled,
                size: 200.0,
                color: Colors.white54,
              ),
              Text(
                'Bluetooth Adapter is ${adapterState != null ? adapterState.toString().split(".").last : 'not available'}.',
                style: Theme.of(context).primaryTextTheme.titleSmall?.copyWith(color: Colors.white),
              ),
              if (Platform.isAndroid)
                ElevatedButton(
                  child: const Text('TURN ON'),
                  onPressed: () async {
                    try {
                      if (Platform.isAndroid) {
                        await FlutterBluePlus.turnOn();
                      }
                    } catch (e) {
                      final snackBar = snackBarFail(prettyException("Error Turning On:", e));
                      snackBarKeyA.currentState?.removeCurrentSnackBar();
                      snackBarKeyA.currentState?.showSnackBar(snackBar);
                    }
                  },
                ),
            ],
          ),
        ),
      ),
    );
  }
}

class FindDevicesScreen extends StatefulWidget {
  const FindDevicesScreen({Key? key}) : super(key: key);

  @override
  State<FindDevicesScreen> createState() => _FindDevicesScreenState();
}

class _FindDevicesScreenState extends State<FindDevicesScreen> {
  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyB,
      child: Scaffold(
        appBar: AppBar(

```

--------------------------------

### Main Application Setup and Permissions

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.7.4/example

Initializes the Flutter application, requests necessary Bluetooth and location permissions on Android, and starts the main app widget. On other platforms, it directly runs the app.

```dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';
import 'package:permission_handler/permission_handler.dart';

import 'widgets.dart';

void main() {

  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [ 
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
      runApp(const FlutterBlueApp());
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothState>(
          stream: FlutterBluePlus.instance.state,
          initialData: BluetoothState.unknown,
          builder: (c, snapshot) {
            final state = snapshot.data;
            if (state == BluetoothState.on) {
              return const FindDevicesScreen();
            }
            return BluetoothOffScreen(state: state);
          }),
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.state}) : super(key: key);

  final BluetoothState? state;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.lightBlue,
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            const Icon(
              Icons.bluetooth_disabled,
              size: 200.0,
              color: Colors.white54,
            ),
            Text(
              'Bluetooth Adapter is ${state != null ? state.toString().substring(15) : 'not available'}.',
              style: Theme.of(context)
                  .primaryTextTheme
                  .subtitle2
                  ?.copyWith(color: Colors.white),
            ),
            ElevatedButton(
              child: const Text('TURN ON'),
              onPressed: Platform.isAndroid
                  ? () => FlutterBluePlus.instance.turnOn()
                  : null,
            ),
          ],
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Find Devices'),
        actions: [
          ElevatedButton(
            child: const Text('TURN OFF'),
            style: ElevatedButton.styleFrom(
              primary: Colors.black,
              onPrimary: Colors.white,
            ),
            onPressed: Platform.isAndroid
                ? () => FlutterBluePlus.instance.turnOff()
                : null,
          ),
        ],
      ),
      body: RefreshIndicator(
        onRefresh: () => FlutterBluePlus.instance
            .startScan(timeout: const Duration(seconds: 4)),
        child: SingleChildScrollView(
          child: Column(
            children: <Widget>[
              StreamBuilder<List<BluetoothDevice>>(
                stream: Stream.periodic(const Duration(seconds: 2))
                    .asyncMap((_) => FlutterBluePlus.instance.connectedDevices),
                initialData: const [],
                builder: (c, snapshot) => Column(
                  children: snapshot.data!
                      .map((d) => ListTile(
                            title: Text(d.name),
                            subtitle: Text(d.id.toString()),
                            trailing: StreamBuilder<BluetoothDeviceState>(
                              stream: d.state,
                              initialData: BluetoothDeviceState.disconnected,
                              builder: (c, snapshot) {
                                if (snapshot.data ==
                                    BluetoothDeviceState.connected) {
                                  return ElevatedButton(
                                    child: const Text('OPEN'),
                                    onPressed: () => Navigator.of(context).push(
                                        MaterialPageRoute(
                                            builder: (context) =>
                                                DeviceScreen(device: d))),
                                  );
                                }
                                return Text(snapshot.data.toString());
                              }
                            ),
                          ))
                      .toList(),
                ),
              )
            ],
          ),
        ),
      ),
    );
  }
}

class DeviceScreen extends StatelessWidget {
  const DeviceScreen({Key? key, required this.device}) : super(key: key);

  final BluetoothDevice device;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(device.name),
        actions: <Widget>[
          StreamBuilder<BluetoothDeviceState>(
            stream: device.state,
            initialData: BluetoothDeviceState.connecting,
            builder: (c, snapshot) => (snapshot.data == BluetoothDeviceState.connected)
                ? TextButton(
                    child: const Text(
                      'DISCONNECT',
                      style: TextStyle(color: Colors.white),
                    ),
                    onPressed: () async {
                      await device.disconnect();
                      Navigator.of(context).pop();
                    },
                  )
                : Text(''),
          )
        ],
      ),
      body: ListView(
        children:
          <Widget>[
            StreamBuilder<BluetoothDeviceState>(
              stream: device.state,
              initialData: BluetoothDeviceState.connecting,
              builder: (c, snapshot) => ListTile(
                leading: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: <Widget>[
                    Icon(snapshot.data == BluetoothDeviceState.connected
                        ? Icons.bluetooth_connected
                        : Icons.bluetooth_ \\_off),
                    if (snapshot.data == BluetoothDeviceState.connected)
                      StreamBuilder<num>(
                        stream: device.mtu,
                        initialData: 0,
                        builder: (c, snapshot) =>
                            Text(snapshot.data.toString() + ' mtu'),
                      )
                  ],
                ),
                title: Text(
                    'Device is ${snapshot.data.toString().split('.')[1]} with RSSI: ${device.rssi}'
                ),
              ),
            ),
            StreamBuilder<List<BluetoothService>>(
              stream: device.discoverServices(),
              builder: (c, snapshot) {
                returnЕЛ
                  Column(
                    children:
                      snapshot.data?.map((s) => ServiceTile(service: s)).toList() ??
                          [],
                  );
              },
            ),
          ].where((w) => w != null).toList(),
      ),
    );
  }
}

class ServiceTile extends StatelessWidget {
  const ServiceTile({Key? key, required this.service}) : super(key: key);

  final BluetoothService service;

  @override
  Widget build(BuildContext context) {
    return Column(children: [
      ListTile(
        title: Text('SERVICE'),
        subtitle: Text(service.uuid.toString().shortFormat),
      ),
      if (service.characteristics.isNotEmpty)
        ...service.characteristics.map((c) => CharacteristicTile(characteristic: c)).toList() ??
            [],
    ]);
  }
}

class CharacteristicTile extends StatelessWidget {
  const CharacteristicTile({Key? key, required this.characteristic}) : super(key: key);

  final BluetoothCharacteristic characteristic;

  @override
  Widget build(BuildContext context) {
    return ListTile(
      title:
          Text(characteristic.uuid.toString().shortFormat),
      subtitle: Text(characteristic.properties.toString()),
      trailing:
          StreamBuilder<List<int>>(
            stream: characteristic.value,
            initialData: [],
            builder: (c, snapshot) => Row(
              mainAxisSize: MainAxisSize.min,
              children: [
                Text(snapshot.data.toString()),
                if (characteristic.properties.read)
                  TextButton(
                      child: const Text('READ'),
                      onPressed: () async {
                        await characteristic.read();
                      }),
                if (characteristic.properties.write)
                  TextButton(
                      child: const Text('WRITE'),
                      onPressed: () async {
                        await characteristic.write([0x10, 0x11, 0x12], withoutResponse: false);
                      }),
                if (characteristic.properties.notify)
                  TextButton(
                      child: const Text('NOTIFY'),
                      onPressed: () async {
                        await characteristic.setNotifyValue(true);
                      }),
              ].where((w) => w != null).toList(),
            ),
          ),
    );
  }
}

extension on String {
  String shortFormat() {
    return replaceRange(8, null, '…');
  }
}

```

--------------------------------

### Start Bluetooth Scan

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.11.6/example

This example demonstrates how to initiate a Bluetooth scan with a specified timeout and configuration for Android. It checks if a scan is already in progress.

```dart
onRefresh: () {
            if (FlutterBluePlus.isScanningNow == false) {
              return FlutterBluePlus.startScan(timeout: const Duration(seconds: 15), androidUsesFineLocation: false);
            }
            return Future.value();
          },
```

--------------------------------

### Main Application Setup

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.11.1/example

Sets up the main Flutter application, handling Bluetooth permissions on Android and initializing the app based on the Bluetooth adapter state.

```dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

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

import 'widgets.dart';

final snackBarKeyA = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyB = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyC = GlobalKey<ScaffoldMessengerState>();

void main() {
  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [ 
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
    runApp(const FlutterBlueApp());
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothAdapterState>(
          stream: FlutterBluePlus.adapterState,
          initialData: BluetoothAdapterState.unknown,
          builder: (c, snapshot) {
            final adapterState = snapshot.data;
            if (adapterState == BluetoothAdapterState.on) {
              return const FindDevicesScreen();
            }
            return BluetoothOffScreen(adapterState: adapterState);
          }),
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.adapterState}) : super(key: key);

  final BluetoothAdapterState? adapterState;

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyA,
      child: Scaffold(
        backgroundColor: Colors.lightBlue,
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              const Icon(
                Icons.bluetooth_disabled,
                size: 200.0,
                color: Colors.white54,
              ),
              Text(
                'Bluetooth Adapter is ${adapterState != null ? adapterState.toString().split(".").last : 'not available'}.',
                style: Theme.of(context).primaryTextTheme.titleSmall?.copyWith(color: Colors.white),
              ),
              ElevatedButton(
                child: const Text('TURN ON'),
                onPressed: () async {
                  try {
                    if (Platform.isAndroid) {
                      await FlutterBluePlus.turnOn();
                    }
                  } catch (e) {
                    final snackBar = SnackBar(content: Text(prettyException("Error Turning On:", e)));
                    snackBarKeyA.currentState?.showSnackBar(snackBar);
                  }
                },
              ),
            ],
          ),
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyB,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Find Devices'),
          actions: [
            if (Platform.isAndroid)
              ElevatedButton(
                child: const Text('TURN OFF'),
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.black,
                  foregroundColor: Colors.white,
                ),
                onPressed: () async {
                  try {
                    if (Platform.isAndroid) {
                      await FlutterBluePlus.turnOff();
                    }
                  } catch (e) {
                    final snackBar = SnackBar(content: Text(prettyException("Error Turning On:", e)));
                    snackBarKeyB.currentState?.showSnackBar(snackBar);
                  }
                },
              ),
          ],
        ),
        body: RefreshIndicator(
          onRefresh: () => FlutterBluePlus.startScan(
              timeout: const Duration(seconds: 15),
              androidUsesFineLocation: false),
          child: SingleChildScrollView(
            child: Column(
              children: <Widget>[
                StreamBuilder<List<BluetoothDevice>>(
                  stream: Stream.periodic(const Duration(seconds: 2))
                      .asyncMap((_) => FlutterBluePlus.connectedSystemDevices),
                  initialData: const [],

```

--------------------------------

### Main Application Setup

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.11.8/example

Sets up the main Flutter application, handling platform-specific Bluetooth permissions on Android and initializing the app. It also includes logic to display the appropriate screen based on the Bluetooth adapter's state.

```dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

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

import 'widgets.dart';

final snackBarKeyA = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyB = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyC = GlobalKey<ScaffoldMessengerState>();

void main() {
  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [ 
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
    runApp(const FlutterBlueApp());
  }
}

class BluetoothAdapterStateObserver extends NavigatorObserver {
  StreamSubscription<BluetoothAdapterState>? _btStateSubscription;

  @override
  void didPush(Route route, Route? previousRoute) {
    super.didPush(route, previousRoute);
    if (route.settings.name == '/deviceScreen') {
      // Start listening to Bluetooth state changes when a new route is pushed
      _btStateSubscription ??= FlutterBluePlus.adapterState.listen((state) {
        if (state != BluetoothAdapterState.on) {
          // Pop the current route if Bluetooth is off
          navigator?.pop();
        }
      });
    }
  }

  @override
  void didPop(Route route, Route? previousRoute) {
    super.didPop(route, previousRoute);
    // Cancel the subscription when the route is popped
    _btStateSubscription?.cancel();
    _btStateSubscription = null;
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothAdapterState>(
          stream: FlutterBluePlus.adapterState,
          initialData: BluetoothAdapterState.unknown,
          builder: (c, snapshot) {
            final adapterState = snapshot.data;
            if (adapterState == BluetoothAdapterState.on) {
              return const FindDevicesScreen();
            } else {
              FlutterBluePlus.stopScan();
              return BluetoothOffScreen(adapterState: adapterState);
            }
          }),
      navigatorObservers: [BluetoothAdapterStateObserver()],
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.adapterState}) : super(key: key);

  final BluetoothAdapterState? adapterState;

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyA,
      child: Scaffold(
        backgroundColor: Colors.lightBlue,
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              const Icon(
                Icons.bluetooth_disabled,
                size: 200.0,
                color: Colors.white54,
              ),
              Text(
                'Bluetooth Adapter is ${adapterState != null ? adapterState.toString().split(".").last : 'not available'}.',
                style: Theme.of(context).primaryTextTheme.titleSmall?.copyWith(color: Colors.white),
              ),
              if (Platform.isAndroid)
                ElevatedButton(
                  child: const Text('TURN ON'),
                  onPressed: () async {
                    try {
                      if (Platform.isAndroid) {
                        await FlutterBluePlus.turnOn();
                      }
                    } catch (e) {
                      final snackBar = SnackBar(content: Text(prettyException("Error Turning On:", e)));
                      snackBarKeyA.currentState?.showSnackBar(snackBar);
                    }
                  },
                ),
            ],
          ),
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyB,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Find Devices'),
          actions: [
            if (Platform.isAndroid)
              ElevatedButton(
                child: const Text('TURN OFF'),
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.black,
                  foregroundColor: Colors.white,

```

--------------------------------

### Find Devices Screen State

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.16.1/example

Represents the stateful widget for the screen that finds Bluetooth devices. This is the starting point for device discovery in the example app.

```dart
class FindDevicesScreen extends StatefulWidget {
  const FindDevicesScreen({Key? key}) : super(key: key);

  @override
  State<FindDevicesScreen> createState() => _FindDevicesScreenState();
}

class _FindDevicesScreenState extends State<FindDevicesScreen> {

```

--------------------------------

### Main Application Setup and Permission Handling

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.12.10/example

Initializes the Flutter application, requests necessary Bluetooth and location permissions on Android, and sets up the main app widget. Handles Bluetooth adapter state to display appropriate UI.

```dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

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

import 'widgets.dart';

final snackBarKeyA = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyB = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyC = GlobalKey<ScaffoldMessengerState>();

void main() {
  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [ 
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
    runApp(const FlutterBlueApp());
  }
}

class BluetoothAdapterStateObserver extends NavigatorObserver {
  StreamSubscription<BluetoothAdapterState>? _btStateSubscription;

  @override
  void didPush(Route route, Route? previousRoute) {
    super.didPush(route, previousRoute);
    if (route.settings.name == '/deviceScreen') {
      // Start listening to Bluetooth state changes when a new route is pushed
      _btStateSubscription ??= FlutterBluePlus.adapterState.listen((state) {
        if (state != BluetoothAdapterState.on) {
          // Pop the current route if Bluetooth is off
          navigator?.pop();
        }
      });
    }
  }

  @override
  void didPop(Route route, Route? previousRoute) {
    super.didPop(route, previousRoute);
    // Cancel the subscription when the route is popped
    _btStateSubscription?.cancel();
    _btStateSubscription = null;
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothAdapterState>(
          stream: FlutterBluePlus.adapterState,
          initialData: BluetoothAdapterState.unknown,
          builder: (c, snapshot) {
            final adapterState = snapshot.data;
            if (adapterState == BluetoothAdapterState.on) {
              return const FindDevicesScreen();
            } else {
              FlutterBluePlus.stopScan();
              return BluetoothOffScreen(adapterState: adapterState);
            }
          }),
      navigatorObservers: [BluetoothAdapterStateObserver()],
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.adapterState}) : super(key: key);

  final BluetoothAdapterState? adapterState;

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyA,
      child: Scaffold(
        backgroundColor: Colors.lightBlue,
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              const Icon(
                Icons.bluetooth_disabled,
                size: 200.0,
                color: Colors.white54,
              ),
              Text(
                'Bluetooth Adapter is ${adapterState != null ? adapterState.toString().split(".").last : 'not available'}.',
                style: Theme.of(context).primaryTextTheme.titleSmall?.copyWith(color: Colors.white),
              ),
              if (Platform.isAndroid)
                ElevatedButton(
                  child: const Text('TURN ON'),
                  onPressed: () async {
                    try {
                      if (Platform.isAndroid) {
                        await FlutterBluePlus.turnOn();
                      }
                    } catch (e) {
                      final snackBar = SnackBar(content: Text(prettyException("Error Turning On:", e)));
                      snackBarKeyA.currentState?.showSnackBar(snackBar);
                    }
                  },
                ),
            ],
          ),
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyB,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Find Devices'),
        ),
        body: RefreshIndicator(
          onRefresh: () {
            if (FlutterBluePlus.isScanningNow == false) {
              return FlutterBluePlus.startScan(timeout: const Duration(seconds: 15), androidUsesFineLocation: false);
            }
            return Future.value();

```

--------------------------------

### Main Application Setup and Permissions

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.12.6/example

Initializes the Flutter application, requests necessary Bluetooth and location permissions on Android, and sets up the main app structure with adapter state observation.

```dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';

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

import 'widgets.dart';

final snackBarKeyA = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyB = GlobalKey<ScaffoldMessengerState>();
final snackBarKeyC = GlobalKey<ScaffoldMessengerState>();

void main() {
  if (Platform.isAndroid) {
    WidgetsFlutterBinding.ensureInitialized();
    [ 
      Permission.location,
      Permission.storage,
      Permission.bluetooth,
      Permission.bluetoothConnect,
      Permission.bluetoothScan
    ].request().then((status) {
      runApp(const FlutterBlueApp());
    });
  } else {
    runApp(const FlutterBlueApp());
  }
}

class BluetoothAdapterStateObserver extends NavigatorObserver {
  StreamSubscription<BluetoothAdapterState>? _btStateSubscription;

  @override
  void didPush(Route route, Route? previousRoute) {
    super.didPush(route, previousRoute);
    if (route.settings.name == '/deviceScreen') {
      // Start listening to Bluetooth state changes when a new route is pushed
      _btStateSubscription ??= FlutterBluePlus.adapterState.listen((state) {
        if (state != BluetoothAdapterState.on) {
          // Pop the current route if Bluetooth is off
          navigator?.pop();
        }
      });
    }
  }

  @override
  void didPop(Route route, Route? previousRoute) {
    super.didPop(route, previousRoute);
    // Cancel the subscription when the route is popped
    _btStateSubscription?.cancel();
    _btStateSubscription = null;
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      color: Colors.lightBlue,
      home: StreamBuilder<BluetoothAdapterState>(
          stream: FlutterBluePlus.adapterState,
          initialData: BluetoothAdapterState.unknown,
          builder: (c, snapshot) {
            final adapterState = snapshot.data;
            if (adapterState == BluetoothAdapterState.on) {
              return const FindDevicesScreen();
            } else {
              FlutterBluePlus.stopScan();
              return BluetoothOffScreen(adapterState: adapterState);
            }
          }),
      navigatorObservers: [BluetoothAdapterStateObserver()],
    );
  }
}

class BluetoothOffScreen extends StatelessWidget {
  const BluetoothOffScreen({Key? key, this.adapterState}) : super(key: key);

  final BluetoothAdapterState? adapterState;

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyA,
      child: Scaffold(
        backgroundColor: Colors.lightBlue,
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              const Icon(
                Icons.bluetooth_disabled,
                size: 200.0,
                color: Colors.white54,
              ),
              Text(
                'Bluetooth Adapter is ${adapterState != null ? adapterState.toString().split(".").last : 'not available'}.',
                style: Theme.of(context).primaryTextTheme.titleSmall?.copyWith(color: Colors.white),
              ),
              if (Platform.isAndroid)
                ElevatedButton(
                  child: const Text('TURN ON'),
                  onPressed: () async {
                    try {
                      if (Platform.isAndroid) {
                        await FlutterBluePlus.turnOn();
                      }
                    } catch (e) {
                      final snackBar = SnackBar(content: Text(prettyException("Error Turning On:", e)));
                      snackBarKeyA.currentState?.showSnackBar(snackBar);
                    }
                  },
                ),
            ],
          ),
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return ScaffoldMessenger(
      key: snackBarKeyB,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Find Devices'),
          actions: [
            if (Platform.isAndroid)
              ElevatedButton(
                child: const Text('TURN OFF'),
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.black,
                  foregroundColor: Colors.white,
                ),
                onPressed: () async {
                  try {
                    if (Platform.isAndroid) {
                      await FlutterBluePlus.turnOff();
                    }
                  } catch (e) {
                    final snackBar = SnackBar(content: Text(prettyException("Error Turning Off:", e)));
                    snackBarKeyB.currentState?.showSnackBar(snackBar);
                  }
                },
              )
          ],
        ),
        body: RefreshIndicator(
          onRefresh: () => FlutterBluePlus.startScan(timeout: const Duration(seconds: 4)),
          child: ListView(
            children:
              <Widget>[
                StreamBuilder<BluetoothAdapterState>(
                  stream: FlutterBluePlus.adapterState,
                  builder: (context, snapshot) {
                    final adapterState = snapshot.data;
                    return BluetoothStats(
                      adapterState: adapterState ?? BluetoothAdapterState.unknown,
                    );
                  }
                ),
                StreamBuilder<List<ScanResult>>(
                  stream: FlutterBluePlus.scanResults,
                  initialData: const [],
                  builder: (c, snapshot) => Column(
                    children: snapshot.data
                        ?.where((r) => r.device.name.isNotEmpty)
                        .toList()!
                        .sort(
                            (a, b) => a.device.name.compareTo(b.device.name))
                        .map((r) => DeviceTile(device: r.device, onTap: () {
                              FlutterBluePlus.stopScan();
                              Navigator.of(context).push(
                                MaterialPageRoute(builder: (c) {
                                  return DeviceScreen(device: r.device);
                                }),
                              );
                            }))
                        .toList() ?? [],
                  ),
                )
              ].toList(),
          ),
        ),
      ),
    );
  }
}

```

--------------------------------

### Run Example App

Source: https://pub.dev/packages/flutter_blue_plus

Navigate to the example directory and run the example app to test the plugin's functionality.

```bash
cd ./example
flutter run
```

--------------------------------

### Example: Fix deprecations

Source: https://pub.dev/packages/flutter_blue_plus/versions/1.7.8/changelog

Deprecations within the example project have been addressed. This ensures the example code is up-to-date with current Flutter and Dart practices.

```dart
Example: fix deprecations
```