我正在尝试使用 Xamarin/Android 为多个 BLE 特性启用通知,但似乎无法这样做。如果我尝试一次启用多个事件,该应用程序似乎停止接收任何 BLE 事件。
任何人都可以使用 Tamarin/Android 确认这是否可行。我们有一个原生 iOS 应用程序,它可以在启用多个通知的情况下正常工作。我们使用的基本步骤如下:
- 扫描设备
- 连接到设备
- 发现服务
- 对于每个发现的服务,遍历特征并启用所需的特征
- 处理BLE回调中的每个异步回调事件
每当我们尝试启用多个特征的通知时,我们都不会再收到任何事件。
我也找不到任何启用多个特性的示例。
我希望我只是错过了一些关于在这里使用 Xamarin/Android API 的基本知识。
public override void OnServicesDiscovered (BluetoothGatt gatt, GattStatus status)
{
base.OnServicesDiscovered (gatt, status);
foreach (BluetoothGattService service in gatt.Services) {
string uuid = service.Uuid.ToString ().ToUpper();
if (uuid.Equals (BLEServices.HRService.ToUpper())) {
_Adap.LogMessage ("HRService discovered");
foreach(BluetoothGattCharacteristic characteristic in service.Characteristics) {
string c_uuid = characteristic.Uuid.ToString ().ToUpper ();
_Adap.LogMessage (" HRCharacteristic: " + c_uuid);
if (c_uuid.Equals(_Adap.useCharacteristic.ToUpper())) {
_Adap.LogMessage (" enabling HRCharacteristic");
gatt.SetCharacteristicNotification(characteristic, true);
BluetoothGattDescriptor descriptor = new BluetoothGattDescriptor (Java.Util.UUID.FromString (BLEServices.CLIENT_CHARACTERISTIC_CONFIG), GattDescriptorPermission.Write | GattDescriptorPermission.Read);
characteristic.AddDescriptor (descriptor);
descriptor.SetValue (BluetoothGattDescriptor.EnableNotificationValue.ToArray ());
gatt.WriteDescriptor (descriptor);
_Adap.StartTimer ();
}
}
} else if (uuid.Equals (BLEServices.BatteryService.ToUpper())) {
_Adap.LogMessage ("BatteryService discovered");
foreach (BluetoothGattCharacteristic characteristic in service.Characteristics) {
string c_uuid = characteristic.Uuid.ToString ().ToUpper ();
_Adap.LogMessage (" BatteryService: " + c_uuid);
if (c_uuid.Equals (_Adap.useCharacteristic.ToUpper ())) {
_Adap.LogMessage (" reading batteryCharacteristic");
// This may only be reported when the battery level changes so get the level first by doing a read
gatt.ReadCharacteristic (characteristic);
//gatt.SetCharacteristicNotification (characteristic, true);
//BluetoothGattDescriptor descriptor = new BluetoothGattDescriptor (Java.Util.UUID.FromString (BLEServices.CLIENT_CHARACTERISTIC_CONFIG), GattDescriptorPermission.Write | GattDescriptorPermission.Read);
//characteristic.AddDescriptor (descriptor);
//descriptor.SetValue (BluetoothGattDescriptor.EnableNotificationValue.ToArray ());
//gatt.WriteDescriptor (descriptor);
}
}
} else if (uuid.Equals (BLEServices.DeviceInfoService.ToUpper())) {
_Adap.LogMessage ("DeviceInfoService discovered");
foreach (BluetoothGattCharacteristic characteristic in service.Characteristics) {
string c_uuid = characteristic.Uuid.ToString ().ToUpper ();
_Adap.LogMessage (" DeviceInfoService: " + c_uuid);
if (c_uuid.Equals (BLEServices.kModelNumberCharacteristicUuidString.ToUpper ())) {
//gatt.ReadCharacteristic (characteristic);
}
}
} else if (uuid.Equals (BLEServices.kHxM2CustomServiceUuidString.ToUpper())) {
_Adap.LogMessage ("HxM2CustomService discovered");
foreach (BluetoothGattCharacteristic characteristic in service.Characteristics) {
string c_uuid = characteristic.Uuid.ToString ().ToUpper ();
_Adap.LogMessage (" HxM2CustomCharacteristic: " + c_uuid);
if (c_uuid.Equals (_Adap.useCharacteristic.ToUpper ())) {
_Adap.LogMessage (" enabling HxM2 characteristic: "+_Adap.useCharacteristic);
gatt.SetCharacteristicNotification (characteristic, true);
BluetoothGattDescriptor descriptor = new BluetoothGattDescriptor (Java.Util.UUID.FromString (BLEServices.CLIENT_CHARACTERISTIC_CONFIG), GattDescriptorPermission.Write | GattDescriptorPermission.Read);
characteristic.AddDescriptor (descriptor);
descriptor.SetValue (BluetoothGattDescriptor.EnableNotificationValue.ToArray ());
gatt.WriteDescriptor (descriptor);
// Start a timer to make sure that we can recover if we never receive any data from the device
_Adap.StartTimer ();
}
}
} else {
_Adap.LogMessage ("Unknown Service "+uuid+" discovered");
}
}
}
谁能解释以下几行的用途
BluetoothGattDescriptor descriptor = new BluetoothGattDescriptor (Java.Util.UUID.FromString (BLEServices.CLIENT_CHARACTERISTIC_CONFIG), GattDescriptorPermission.Write | GattDescriptorPermission.Read);
characteristic.AddDescriptor (descriptor);
descriptor.SetValue (BluetoothGattDescriptor.EnableNotificationValue.ToArray ());
gatt.WriteDescriptor (descriptor);