I am not able to understand the usage of Q_PROPERTY. How th Q_PROPERTY helps in making a program defensive? What is it used for? I have seen the forum, but really not able to make its applicaton. I have understood the example, but not it's usage.
Here is the example, what do I gain with it. I understand that read will give a privilege of reading only.
The write property will give the privilege to write only. But what is the need of it? Can someone exemplify it?
class MyClass : public QObject { Q_OBJECT Q_PROPERTY(Priority priority READ priority WRITE setPriority NOTIFY priorityChanged) Q_ENUMS(Priority) public: MyClass(QObject *parent = 0); ~MyClass(); enum Priority { High, Low, VeryHigh, VeryLow }; void setPriority(Priority priority) { m_priority = priority; emit priorityChanged(priority); } Priority priority() const { return m_priority; } signals: void priorityChanged(Priority); private: Priority m_priority; };
It has the following advantages:
It is available for the meta object system, so it can be introspected, used from QML etc.
It has further options than just read and write. Look at notify, reset, etc. It is also easier to integrate them into QtCreator (designer).
You do not need to write the boilerplate with Qt 5.1 onwards in common read and write cases because they will be generated for you.
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