本系列所有文章可以在这里查看[http://blog.csdn.net/cloud_castle/article/category/2123873](http://blog.csdn.net/cloud_castle/article/category/2123873) 接上文[Qt5官方demo解析集21——Extending QML - Adding Types Example](http://blog.csdn.net/cloud_castle/article/details/37055429) 在上一个例子中我们基于C++创建了一个自定义的QML类型,接下来,我们将该类作为另一个类的属性类型,定义了另一个birthdayparty类。这个例子与[Qt5官方demo解析集19——Chapter 5: Using List Property Types](http://blog.csdn.net/cloud_castle/article/details/36898495)是十分相似的,只不过在这个例子中只提供了对列表属性的访问能力。[](http://blog.csdn.net/cloud_castle/article/details/36898495) 项目文件如下: ![](https://box.kancloud.cn/2016-01-18_569cbd083f9a1.jpg) Person的定义和声明与上一篇博文中所贴出的一致,因此我们先看看birthdayparty.h: ~~~ #ifndef BIRTHDAYPARTY_H #define BIRTHDAYPARTY_H #include <QObject> #include <QQmlListProperty> // 这个类型我们在解析集19中有讨论过,它用来提供带有列表成员的属性 #include "person.h" // ![0] class BirthdayParty : public QObject { Q_OBJECT // ![0] // ![1] Q_PROPERTY(Person *host READ host WRITE setHost) // host属性,指向一个Person对象 // ![1] // ![2] Q_PROPERTY(QQmlListProperty<Person> guests READ guests) // guests属性,指向一个Person列表 // ![2] // ![3] public: BirthdayParty(QObject *parent = 0); Person *host() const; void setHost(Person *); QQmlListProperty<Person> guests(); // 上面是属性的读写函数 int guestCount() const; // 下面是自定义的用来返回客人数与读取某个客人的函数 Person *guest(int) const; private: Person *m_host; QList<Person *> m_guests; // 对应的需要将m_guests定义成QList<Person *>类型的成员列表 }; // ![3] #endif // BIRTHDAYPARTY_H ~~~ birthdayparty.cpp: ~~~ #include "birthdayparty.h" BirthdayParty::BirthdayParty(QObject *parent) : QObject(parent), m_host(0) // 初始化参数赋值,这个0相当于NULL { } // ![0] Person *BirthdayParty::host() const { return m_host; } void BirthdayParty::setHost(Person *c) { m_host = c; } QQmlListProperty<Person> BirthdayParty::guests() { return QQmlListProperty<Person>(this, m_guests); // 由一个QList得到QQmlListProperty值,函数原型如下 } int BirthdayParty::guestCount() const // 数据成员一般都为私有,要调用它的函数,我们需要提供一个公共的接口 { return m_guests.count(); } Person *BirthdayParty::guest(int index) const { return m_guests.at(index); } ~~~ ![](https://box.kancloud.cn/2016-01-18_569cbd084e8e6.jpg) example.qml: ~~~ import People 1.0 // 由于在main函数中将Person与Birthdayparty的名称空间均注册为People 1.0,导入它我们可以同时使用这两个类型 // ![0] BirthdayParty { host: Person { // host参数为单Person name: "Bob Jones" shoeSize: 12 } guests: [ // guests参数为多Person Person { name: "Leo Hodges" }, Person { name: "Jack Smith" }, Person { name: "Anne Brown" } ] } // ![0] ~~~ main.cpp: ~~~ #include <QCoreApplication> #include <QQmlEngine> #include <QQmlComponent> #include <QDebug> #include "birthdayparty.h" #include "person.h" int main(int argc, char ** argv) { QCoreApplication app(argc, argv); //![register list] qmlRegisterType<BirthdayParty>("People", 1,0, "BirthdayParty"); // QML类型注册 qmlRegisterType<Person>("People", 1,0, "Person"); //![register list] QQmlEngine engine; QQmlComponent component(&engine, QUrl("qrc:example.qml")); BirthdayParty *party = qobject_cast<BirthdayParty *>(component.create()); if (party && party->host()) { // 由于host为"Bob Jones",该if得以进入 qWarning() << party->host()->name() << "is having a birthday!"; qWarning() << "They are inviting:"; for (int ii = 0; ii < party->guestCount(); ++ii) // 调用公共接口得到客人数 qWarning() << " " << party->guest(ii)->name(); // 逐一访问其姓名 } else { qWarning() << component.errors(); } return 0; } ~~~