PlatformException(error, bluetooth not available, null, null) in Flutter: Causes and How to Fix

Verify Permissions

• Ensure that your app has the necessary permissions to access Bluetooth. This can usually be done by checking the AndroidManifest.xml and Info.plist files for the required Bluetooth permissions.

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.yourapp">

    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

    <application
        android:label="YourApp">
        <!-- Other configurations -->

    </application>
</manifest>

Check for Platform Specific Implementation

• For Android, ensure the Bluetooth adapter is initialized properly in your custom platform channel implementations. Do this in the MainActivity or the respective platform-specific file.

import android.bluetooth.BluetoothAdapter

class MainActivity: FlutterActivity() {

    private val bluetoothAdapter: BluetoothAdapter? = BluetoothAdapter.getDefaultAdapter()

    // Your additional code to manage Bluetooth states
}

• For iOS, make sure CoreBluetooth framework is linked correctly in your Xcode project, and handling states are managed properly in your AppDelegate.swift or Objective-C implementations.

import CoreBluetooth

class AppDelegate: UIResponder, UIApplicationDelegate {

    var bluetoothManager: CBCentralManager?

    func application(_ application: UIApplication,
                     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        bluetoothManager = CBCentralManager(delegate: self, queue: nil)
        return true
    }
}

Use Proper Dependencies

• Ensure that you are using a reliable and updated Bluetooth plugin/package for Flutter. Check the package documentation for any specific setup instructions.

dependencies:
  flutter:
    sdk: flutter
  flutter_blue: ^0.8.0

• Run `flutter pub get` to install and integrate the package into your Flutter project.

flutter pub get

Debugging Connections

• Verify the device you are running on supports Bluetooth and that the feature is turned on.

• If using an emulator, note that they generally do not support Bluetooth operations. Testing should be done on actual devices.

import 'package:flutter/services.dart';

Future<void> checkBluetoothStatus() async {
  try {
    final isAvailable = await platformChannel.invokeMethod('checkBluetooth');
    print('Bluetooth is available: $isAvailable');
  } on PlatformException catch (e) {
    print('Error: $e');
  }
}

Test and Verify

• After making the changes, thoroughly test the app on multiple devices to ensure the fixes are correctly implemented.

• Remain attentive to updates from Flutter or the Bluetooth plugin for any additional changes or required fixes in future versions.