android - 不使用BLE调用onCharacteristicChanged

我连接了一个血压计，并在OnServiceIcovered中设置了通知。
我把每一个特征都设置为notify。
但是oncharacteristicchanged仍然不被调用。

public final static UUID CLIENT_UUID = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb");

gatt.setCharacteristicNotification(characteristic, enabled);
for (BluetoothGattDescriptor dp : characteristic.getDescriptors()) {
    dp = characteristic.getDescriptor(CLIENT_UUID);
    if (dp != null) {
      if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_NOTIFY) != 0) {
         descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
      } else if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_INDICATE) != 0) {
         descriptor.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);
      }

    gatt.writeDescriptor(dp);
    }
}


@Override
public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
    super.onCharacteristicChanged(gatt, characteristic);

我想接受血压，但一经改变就再也没打过电话。
但我可以接收ios或其他示例代码。
谢谢您！

最佳答案

首先，Blood Pressure Measurement的性质是Indicate，而不是Notify
https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=org.bluetooth.service.blood_pressure.xml
ios的CBPeripheral setNotifyValue是自动设置Indicate或Notify，但android没有实现。
给你一些代码供参考

if (gatt.setCharacteristicNotification(characteristic, true)) {
    BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
    if (descriptor != null) {
        if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_NOTIFY) != 0) {
            descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
        } else if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_INDICATE) != 0) {
            descriptor.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);
        } else {
            // The characteristic does not have NOTIFY or INDICATE property set;
        }

        if (gatt.writeDescriptor(descriptor)) {
            // Success
        } else {
            // Failed to set client characteristic notification;
        }
    } else {
        // Failed to set client characteristic notification;
    }
} else {
    // Failed to register notification;
}