如何释放蓝牙GATT连接

Question

我有一个应用程序，与GATT心率监测器通信。有时，传感器失败，我想重新初始化连接。我想把连接包装在一个类中，并在旧连接失败时声明一个新对象(参见如何删除对象?)。然后我尝试实现易弃性，但我不确定如何实现。我也考虑过使用CancelationToken，但也不知道如何使用。下面是代码:

public class MainPage : Page
{
    ConnectingObject conn;
    MainPage()
    {
        this.InitializeComponent();
        conn = new ConnectingObject();
    }
    public void cancelConnection()
    {
        conn.Dispose();
    }
}
public class ConnectingObject : IDisposable
{
    bool disposed = false;
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }
    protected virtual void Dispose(bool disposing)
    {
        if (disposed)
            return;
        if (disposing)
        {
            // Free any other managed objects here.
            //
        }
        // Free any unmanaged objects here.
        //
        disposed = true;
    }
    ~HRGATTConnect()
    {
        Dispose(false);
    }
    async void Initialize()
    {
        try
        {
            var heartrateServices = await Windows.Devices.Enumeration
                .DeviceInformation.FindAllAsync(GattDeviceService
                    .GetDeviceSelectorFromUuid(
                        GattServiceUuids.HeartRate),
                null);
            GattDeviceService firstHeartRateMonitorService = await
                GattDeviceService.FromIdAsync(heartrateServices[0].Id);
            //Debug.WriteLine("serviceName:  " +  heartrateServices[0].Name);
            GattCharacteristic hrMonitorCharacteristics =
                firstHeartRateMonitorService.GetCharacteristics(
                    GattCharacteristicUuids.HeartRateMeasurement)[0];
            hrMonitorCharacteristics.ValueChanged += hrMeasurementChanged;
            await hrMonitorCharacteristics
                    .WriteClientCharacteristicConfigurationDescriptorAsync(
                        GattClientCharacteristicConfigurationDescriptorValue.Notify);                
        }
        catch (Exception e)
        {
        }
    }
    void hrMeasurementChanged(GattCharacteristic sender, GattValueChangedEventArgs eventArgs)
    {
        try
        {
            byte[] hrData = new byte[eventArgs.CharacteristicValue.Length];
            Windows.Storage.Streams.DataReader.FromBuffer(
                eventArgs.CharacteristicValue).ReadBytes(hrData);
            data_processing(hrData);                
            }
        }
        catch (Exception e)
        {
        }
    }

谢谢。

Answer 1

如何释放蓝牙GATT连接

你需要在GattDeviceService上调用Dispose()，确保所有的GattDeviceService和GattCharacteristic对象为空。你可以这样编辑你的代码:

public sealed partial class MainPage : Page
{
    ConnectingObject conn;
    public MainPage()
    {
        this.InitializeComponent();
        conn = new ConnectingObject();
    }
    private void Button_Click(object sender, RoutedEventArgs e)
    {
        Frame.Navigate(typeof(BluetoothConnect));
    }
    public void cancelConnection()
    {
        conn.Dispose();
    }
    private void DisconnectButton_Click(object sender, RoutedEventArgs e)
    {
        conn.Dispose();
    }
    private void ConnectButton_Click(object sender, RoutedEventArgs e)
    {
        conn.Initialize();
    }
}
public class ConnectingObject : IDisposable
{
    GattCharacteristic hrMonitorCharacteristics;
    GattDeviceService firstHeartRateMonitorService;
    bool disposed = false;
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }
    protected virtual void Dispose(bool disposing)
    {
        if (disposed)
            return;
        if (disposing)
        {
            // Free any other managed objects here.
            //
            if (firstHeartRateMonitorService != null)
            {
                firstHeartRateMonitorService.Dispose();
                firstHeartRateMonitorService = null;
            }
            if (hrMonitorCharacteristics != null)
            {
                hrMonitorCharacteristics.Service.Dispose();
                hrMonitorCharacteristics = null;
            }
        }
        // Free any unmanaged objects here.
        //
        disposed = true;
    }
    //~HRGATTConnect()
    //{
    //    Dispose(false);
    //}
    public async void Initialize()
    {
        try
        {
            var heartrateServices = await Windows.Devices.Enumeration
                .DeviceInformation.FindAllAsync(GattDeviceService
                    .GetDeviceSelectorFromUuid(
                        GattServiceUuids.HeartRate),
                null);
            firstHeartRateMonitorService = await
                GattDeviceService.FromIdAsync(heartrateServices[0].Id);
            Debug.WriteLine("serviceName:  " + heartrateServices[0].Name);
            hrMonitorCharacteristics =
                firstHeartRateMonitorService.GetCharacteristics(
                    GattCharacteristicUuids.HeartRateMeasurement)[0];
            hrMonitorCharacteristics.ValueChanged += hrMeasurementChanged;
            await hrMonitorCharacteristics
                    .WriteClientCharacteristicConfigurationDescriptorAsync(
                        GattClientCharacteristicConfigurationDescriptorValue.Notify);
            disposed = false;
        }
        catch (Exception e)
        {
        }
    }
    void hrMeasurementChanged(GattCharacteristic sender, GattValueChangedEventArgs eventArgs)
    {
        try
        {
            byte[] hrData = new byte[eventArgs.CharacteristicValue.Length];
            Windows.Storage.Streams.DataReader.FromBuffer(
                eventArgs.CharacteristicValue).ReadBytes(hrData);
            //data_processing(hrData);
        }
        catch (Exception e)
        {
        }
    }
}