Create subscriber on constructor

Author: Tacha-S

nav2_behavior_tree/include/nav2_behavior_tree/plugins/condition/is_battery_low_condition.hpp

@@ -56,6 +56,11 @@ class IsBatteryLowCondition : public BT::ConditionNode
    */
   void initialize();
 
+  /**
+   * @brief Function to create ROS interfaces
+   */
+  void createROSInterfaces();
+
   /**
    * @brief Creates list of BT ports
    * @return BT::PortsList Containing node-specific ports

nav2_behavior_tree/plugins/condition/is_battery_low_condition.cpp

@@ -29,6 +29,7 @@ IsBatteryLowCondition::IsBatteryLowCondition(
   is_voltage_(false),
   is_battery_low_(false)
 {
+  createROSInterfaces();
 }
 
 void IsBatteryLowCondition::initialize()
@@ -41,21 +42,25 @@ void IsBatteryLowCondition::initialize()
   // Only create a new subscriber if the topic has changed or subscriber is empty
   if (battery_topic_new != battery_topic_ || !battery_sub_) {
     battery_topic_ = battery_topic_new;
+    createROSInterfaces();
+  }
+}
 
-    node_ = config().blackboard->get<rclcpp::Node::SharedPtr>("node");
-    callback_group_ = node_->create_callback_group(
-      rclcpp::CallbackGroupType::MutuallyExclusive,
-      false);
-    callback_group_executor_.add_callback_group(callback_group_, node_->get_node_base_interface());
+void IsBatteryLowCondition::createROSInterfaces()
+{
+  node_ = config().blackboard->get<rclcpp::Node::SharedPtr>("node");
+  callback_group_ = node_->create_callback_group(
+    rclcpp::CallbackGroupType::MutuallyExclusive,
+    false);
+  callback_group_executor_.add_callback_group(callback_group_, node_->get_node_base_interface());
 
-    rclcpp::SubscriptionOptions sub_option;
-    sub_option.callback_group = callback_group_;
-    battery_sub_ = node_->create_subscription<sensor_msgs::msg::BatteryState>(
-      battery_topic_,
-      rclcpp::SystemDefaultsQoS(),
-      std::bind(&IsBatteryLowCondition::batteryCallback, this, std::placeholders::_1),
-      sub_option);
-  }
+  rclcpp::SubscriptionOptions sub_option;
+  sub_option.callback_group = callback_group_;
+  battery_sub_ = node_->create_subscription<sensor_msgs::msg::BatteryState>(
+    battery_topic_,
+    rclcpp::SystemDefaultsQoS(),
+    std::bind(&IsBatteryLowCondition::batteryCallback, this, std::placeholders::_1),
+    sub_option);
 }
 
 BT::NodeStatus IsBatteryLowCondition::tick()