EWOL: Object config

@tableofcontents

Objectifs:

Understand base of e-property configuration parameter
Create an configurable object

Configuration using

All ewol::Object have a configuration of parameters (the object name is a parameter), then we need to set get and use xml to update parameters.

Set a Parameter/Property

Note:

	Parameter is managed by the [e-property](http://atria-soft.github.io/eproperty)

With a string configuration

	if (tmpObject->properties.set("name", "new name of object") == false) {
		APPL_ERROR("Can not set object parameter");
	}

whith the object name

	if (ewol::propertySetOnObjectNamed("objectName", "value", "16.2") == false) {
		APPL_ERROR("Can not set object parameter");
	}

Get Parameter

	etk::String val = tmpObject->properties.get("name");
	APPL_INFO("Get Object property: name='" << val << "'");

Implement configuration

#include <ewol/object/Object.hpp>
namespace appl {
	class MyObj : public ewol::Object {
		public:
			eproperty::Value<bool> propertyValue; //!< Property interface (all time start with "property")
		protected:
			//! @brief Constructor
			MyObj(void) :
			  propertyValue(this, "value",
			                      false,
			                      "Value of the parameter (descrition string)",
			                      &appl::MyObj::onChangeParameterValue) {
				// nothing to do..
			}
			void init() {
				ewol::Object::init();
				// do some stuff with the init value
			}
		public:
			//! @brief Destructor
			virtual ~MyObj(void) { }
			DECLARE_FACTORY(MyObj);
		public:
			void onChangeParameterValue() {
				APPL_DEBUG("The internal value has change, new value is : '" << *m_value << "'");
			}
	}
}

In the contructor we need to add:

propertyValue(this,
              "value",
              false,
              "Value of the parameter (descrition string)",
              &appl::MyObj::onChangeParameterValue)

'this': Pointer the main class to call it chen value change.
"value": Is the name of the parameter.
false: The default value.
"....." Description of the parameter (optionnal).
&appl::MyObj::onChangeParameterValue The callback when the value change (optionnal).

The last point is that the *propertyValue same as propertyValue.get() are inline fuction then it take no more CPU cycle to access the value than normal variable.

Some other parameter are availlable :

eproperty::Value Basic parameter.
eproperty::Range For numeric parameter that range value are check befor setting new value.
eproperty::List For List of parameter values.

For more information see e-property

3.3 KiB Raw Blame History