onCharacteristicChanged在Android 5.0中不是回调

在安卓4.3中，onCharacteristicChanged是一个回调函数，但在上面的安卓5.0中，它不是调用函数WriteCharacteristic'和SetCharacteristicNotification'已成功，onCharacteristicWrite'回调已成功。为什么在Android5.0或Android 6.0中不调用它

这是我的通知代码：

private void notification(BluetoothGattCharacteristic gattCharacteristic, String tag) {
    boolean success = mBluetoothGatt.setCharacteristicNotification(gattCharacteristic, true);
    if (success) {
        for (BluetoothGattDescriptor dp : gattCharacteristic.getDescriptors()) {
            if (dp != null) {
                if ((gattCharacteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_NOTIFY) != 0) {
                    dp.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
                    Log.i(TAG,"notification NOTIFICATION value = "+ Arrays.toString(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE));
                } else if ((gattCharacteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_INDICATE) != 0) {
                    dp.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);
                    Log.i(TAG,"notification INDICATION value = "+ Arrays.toString(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE));

                }
                mBluetoothGatt.writeDescriptor(dp);
                Log.i(TAG, tag + " notification successful");
            }
        }
    }
}

“BluetoothGatt.writeDescriptor（dp）”失败，它是一个异步线程。当线程繁忙时，停止写入描述符。所以我一个接一个地写描述符。没关系