mrozema / xamarin-bluetooth-le

MvvmCross plugin for BLE : Android/iOS

Bluetooth LE plugin for Xamarin

Xamarin and MvvMCross plugin for accessing the bluetooth functionality. The plugin is based on the BLE implementation of Monkey Robotics.

Important Note: With the term "vanilla" we mean the non MvvmCross/pure Xamarin version. You can use it without MvvmCross, if you download the vanilla package.

Support & Limitations

Platform	Version	Limitations
Xamarin.Android	4.3
Xamarin.iOS	7.0

Installation

Vanilla

// stable
Install-Package Plugin.BLE
// or pre-release (currently the case)
Install-Package Plugin.BLE -Pre


MvvmCross

Install-Package MvvmCross.Plugin.BLE
// or (recommended for now until we release 1.0.0 stable)
Install-Package MvvmCross.Plugin.BLE -Pre

 

Android

Add these permissions to AndroidManifest.xml. For Marshmallow, please follow Requesting Runtime Permissions in Android Marshmallow

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

Sample app

We provide a sample Xamarin.Forms app, that is a basic bluetooth LE scanner. With this app, it's possible to

• check the ble status
• discover devices
• connect/disconnect
• discover the services
• discover the characteristics
• see characteristic details
• read/write and register for notifications of a characteristic

Have a look at the code and use it as starting point to learn about the plugin and play around with it.

Usage

Vanilla

var ble = CrossBluetoothLE.Current;
var adapter = CrossBluetoothLE.Current.Adapter;

MvvmCross

The MvvmCross plugin registers IBluetoothLE and IAdapter as lazy initialized singletons. You can resolve/inject them as any other MvvmCross service. You don't have to resolve/inject both. It depends on your use case.

var ble = Mvx.Resolve<IBluetoothLE>();
var adapter = Mvx.Resolve<IAdapter>();

or

MyViewModel(IBluetoothLE ble, IAdapter adapter)
{
    this.ble = ble;
    this.adapter = adapter;
}

IBluetothLE

Get the bluetooth status

var state = ble.State;

You can also listen for State changes. So you can react if the user turns on/off bluetooth on you smartphone.

ble.StateChanged += (s, e) => 
{
    Debug.WriteLine($"The bluetooth state changed to {e.NewState}");
};

IAdapter

Scan for devices

adapter.DeviceDiscovered += (s,a) => deviceList.Add(a.Device);
await adapter.StartScanningForDevicesAsync();

Connect to device

ConnectToDeviceAync returns a Task that finishes if the device has been connected successful. Otherwise a DeviceConnectionException gets thrown.

try 
{
    await _adapter.ConnectToDeviceAync(device);
}
catch(DeviceConnectionException e)
{
    // ... could not connect to device
}

Get services

var services = await connectedDevice.GetServicesAsync();

or get a specific service:

var service = await connectedDevice.GetServiceAsync(Guid.Parse("ffe0ecd2-3d16-4f8d-90de-e89e7fc396a5"));

Get characteristics

var characteristics = await service.GetCharacteristicsAsync();

or get a specific characteristic:

var characteristic = await service.GetCharacteristicAsync(Guid.Parse("d8de624e-140f-4a22-8594-e2216b84a5f2"));

Read characteristic

var bytes = await characteristic.ReadAsync();

Write characteristic

await characteristic.WriteAsync(bytes);

Characteristic notifications

characteristic.ValueUpdated += (o, args) =>
{
    var bytes = args.Characteristic.Value;
};

characteristic.StartUpdates();

Useful Links

• MvvmCross
• Monkey Robotics

Licence

Apache 2.0