Extending QML - Default Property Example

This example builds on:

The Default Property Example is a minor modification of the Extending QML - Inheritance and Coercion Example that simplifies the specification of a BirthdayParty through the use of a default property.


  BirthdayParty {
      host: Boy {
          name: "Bob Jones"
          shoeSize: 12
      }

      Boy { name: "Leo Hodges" }
      Boy { name: "Jack Smith" }
      Girl { name: "Anne Brown" }
  }

Declaring the BirthdayParty Class

The only difference between this example and the last, is the addition of the DefaultProperty class info annotation.


  class BirthdayParty : public QObject
  {
      Q_OBJECT
      Q_PROPERTY(Person *host READ host WRITE setHost)
      Q_PROPERTY(QQmlListProperty<Person> guests READ guests)
      Q_CLASSINFO("DefaultProperty", "guests")
  public:
      BirthdayParty(QObject *parent = 0);

      Person *host() const;
      void setHost(Person *);

      QQmlListProperty<Person> guests();
      int guestCount() const;
      Person *guest(int) const;

  private:
      Person *m_host;
      QList<Person *> m_guests;
  };

The default property specifies the property to assign to whenever an explicit property is not specified, in the case of the BirthdayParty type the guest property. It is purely a syntactic simplification, the behavior is identical to specifying the property by name, but it can add a more natural feel in many situations. The default property must be either an object or list property.

Running the Example

The main.cpp file in the example includes a simple shell application that loads and runs the QML snippet shown at the beginning of this page.

Files:

Contents

Extending QML - Default Property Example

Declaring the BirthdayParty Class

Running the Example