Can I use the same Bluetooth permission handling code for both Android and iOS in MvvmCross

Overview of Bluetooth Permissions

- Android: Requires specific permissions declared in the `AndroidManifest.xml` file. For Android versions before 12, you need `ACCESS_FINE_LOCATION`, `BLUETOOTH`, and `BLUETOOTH_ADMIN` permissions. For Android 12 and later, you also need `BLUETOOTH_SCAN`, `BLUETOOTH_CONNECT`, and `BLUETOOTH_ADVERTISE` permissions at runtime[1][8].

- iOS: Requires adding specific keys to the `Info.plist` file, such as `UIBackgroundModes` for Bluetooth central or peripheral modes, and usage descriptions like `NSBluetoothPeripheralUsageDescription` and `NSBluetoothAlwaysUsageDescription` for iOS 13 and later[2][4].

Using MvvmCross for Cross-Platform Bluetooth Handling

MvvmCross provides a plugin framework that can be extended to handle Bluetooth permissions. You can use the MvvmCross.Plugin.BLE package, which supports Bluetooth Low Energy (BLE) functionality across platforms, including Android, iOS, and macOS[2][3].

Steps to Implement Cross-Platform Bluetooth Permissions

1. Install MvvmCross.Plugin.BLE:
Use NuGet to install the MvvmCross BLE plugin. This plugin provides a basic structure for handling BLE operations but does not directly manage permissions. You will need to implement permission handling separately for each platform.

bash
   Install-Package MvvmCross.Plugin.BLE
   

2. Implement Platform-Specific Permissions:
- Android: In your Android project, add the necessary permissions to `AndroidManifest.xml`. For runtime permissions, use MvvmCross's dependency injection to request permissions dynamically[1][8].
- iOS: Modify `Info.plist` to include the required Bluetooth keys and descriptions[2][4].

3. Use Dependency Injection for Permission Handling:
Create an interface (e.g., `IBluetoothService`) that defines methods for checking and requesting permissions. Implement this interface on each platform using platform-specific code. Use MvvmCross's dependency injection to resolve the correct implementation based on the platform[1][3].

4. Cross-Platform Logic:
In your shared code, use the injected `IBluetoothService` to handle permissions. This allows you to write cross-platform logic that calls platform-specific implementations for permission handling.

Example Code Structure

Here's a simplified example of how you might structure your code:

csharp
// Shared Code
public interface IBluetoothService
{
    Task CheckPermission();
    Task RequestPermission();
}

public class BluetoothViewModel
{
    private readonly IBluetoothService _bluetoothService;

    public BluetoothViewModel(IBluetoothService bluetoothService)
    {
        _bluetoothService = bluetoothService;
    }

    public async Task EnsureBluetoothPermission()
    {
        var status = await _bluetoothService.CheckPermission();
        if (status != PermissionStatus.Granted)
        {
            await _bluetoothService.RequestPermission();
        }
    }
}

// Android Implementation
[assembly: Dependency(typeof(AndroidBluetoothService))]
public class AndroidBluetoothService : IBluetoothService
{
    public async Task CheckPermission()
    {
        // Android-specific permission check logic
        if (MainActivity.Instance.CheckSelfPermission(Manifest.Permission.BluetoothScan) == (int)Permission.Granted)
        {
            return await Task.FromResult(PermissionStatus.Granted);
        }
        return await Task.FromResult(PermissionStatus.Denied);
    }

    public async Task RequestPermission()
    {
        // Android-specific permission request logic
        ArrayList permissions = new ArrayList();
        permissions.Add(Manifest.Permission.BluetoothScan);
        permissions.Add(Manifest.Permission.BluetoothConnect);
        permissions.Add(Manifest.Permission.BluetoothAdvertise);

        string[] requestPermission = (String[])permissions.ToArray(typeof(string));
        MainActivity.Instance.RequestPermissions(requestPermission, MainActivity.RequestCode);
        return await CheckPermission();
    }
}

// iOS Implementation
[assembly: Dependency(typeof(iOSBluetoothService))]
public class iOSBluetoothService : IBluetoothService
{
    public async Task CheckPermission()
    {
        // iOS-specific permission check logic
        // Typically, iOS permissions are handled through Info.plist and do not require runtime checks
        return await Task.FromResult(PermissionStatus.Granted);
    }

    public async Task RequestPermission()
    {
        // iOS-specific permission request logic
        // Typically not needed as permissions are declared in Info.plist
        return await Task.FromResult(PermissionStatus.Granted);
    }
}

By structuring your code in this way, you can use MvvmCross to handle Bluetooth permissions across different platforms while respecting each platform's unique requirements.