Extending QML - Adding Types Example

Exporting C++ Classes.

The Adding Types Example shows how to add a new object type, Person, to QML. The Person type can be used from QML like this:

import People 1.0

Person {
    name: "Bob Jones"
    shoeSize: 12

Declare the Person Class

All QML types map to C++ types. Here we declare a basic C++ Person class with the two properties we want accessible on the QML type - name and shoeSize. Although in this example we use the same name for the C++ class as the QML type, the C++ class can be named differently, or appear in a namespace.

class Person : public QObject
    Q_PROPERTY(QString name READ name WRITE setName)
    Q_PROPERTY(int shoeSize READ shoeSize WRITE setShoeSize)
    Person(QObject *parent = nullptr);

    QString name() const;
    void setName(const QString &);

    int shoeSize() const;
    void setShoeSize(int);

    QString m_name;
    int m_shoeSize;

Define the Person Class

Person::Person(QObject *parent)
: QObject(parent), m_shoeSize(0)

QString Person::name() const
    return m_name;

void Person::setName(const QString &n)
    m_name = n;

int Person::shoeSize() const
    return m_shoeSize;

void Person::setShoeSize(int s)
    m_shoeSize = s;

The Person class implementation is quite basic. The property accessors simply return members of the object instance.

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.

Example project @ code.qt.io

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