Question

我一直在尝试导出一些QFlags用于QML（主要是从QML中公开的对象的属性中读取它们），但即使在this SO question之后，我仍然会遇到编译器错误：

#ifndef HOLIDAYACTIVITIES_H
#define HOLIDAYACTIVITIES_H

#include <QObject>
#include <QMetaType>
#include <QPair>
#include <QObject>
#include <QDateTime>
#include <QGeoLocation>


namespace HolidayPlanner
{

class Holiday: public QObject {
    Q_OBJECT

    Q_ENUMS(ActivityType)
    Q_ENUMS(TransportType)

public:
    explicit Holiday(QObject* parent = 0);
    virtual ~Holiday();

    enum ActivityType {
        Transportation = 1,
        Lodging = 2,
        Sights = 4,
        Note = 8,
        Food = 16
    };

    enum TransportType {
        Flight = 1,
        Train = 2,
        Subway = 4,
        Bus = 8,
        Foot = 16,
        Other = 32,
        None = 64
    };

    enum ItemRole {
        TypeRole = Qt::UserRole + 1000,
        StartDateRole = Qt::UserRole + 1001,
        EndDateRole = Qt::UserRole + 1002,
        StartPositionRole = Qt::UserRole + 1003,
        EndPositionRole = Qt::UserRole + 1004,
        TaskRole = Qt::UserRole + 1005,
    };

    Q_DECLARE_FLAGS(ActivityTypes, ActivityType)
    Q_FLAGS(ActivityTypes)
    Q_DECLARE_FLAGS(TransportTypes, TransportType)
    Q_FLAGS(ActivityTypes)

};


Q_DECLARE_OPERATORS_FOR_FLAGS(Holiday::ActivityTypes)
Q_DECLARE_OPERATORS_FOR_FLAGS(Holiday::TransportTypes)

}; // namespace HolidayPlanner

Q_DECLARE_METATYPE(HolidayPlanner::Holiday::ActivityType)
Q_DECLARE_METATYPE(HolidayPlanner::Holiday::TransportType)

但是当我发出

时

qmlRegisterType<HolidayPlanner::Holiday::ActivityType>();

代码中的任何地方，我都会

In file included from /usr/include/qt5/QtQml/QtQml:9:0,
             from /home/lb/Coding/cpp/holiday-planner/src/holidayactivities.cpp:21:
 /usr/include/qt5/QtQml/qqml.h: In instantiation of ‘int qmlRegisterType() [with T =     
 HolidayPlanner::Holiday::ActivityType]’:
 /home/lb/Coding/cpp/holiday-planner/src/holidayactivities.cpp:28:60:   required from here
 /usr/include/qt5/QtQml/qqml.h:109:5: error: ‘staticMetaObject’ is not a member of    
 ‘HolidayPlanner::Holiday::ActivityType’
     QML_GETTYPENAMES
     ^
 /usr/include/qt5/QtQml/qqml.h:119:21: error: ‘staticMetaObject’ is not a member of   
 ‘HolidayPlanner::Holiday::ActivityType’
     0, 0, 0, 0, &T::staticMetaObject,
                 ^

这里可能出现什么问题？

作为参考，像QLocale这样的其他类可以将它们的枚举导出到QML（默认情况下没有完成，但是它有效），但是我无法找到任何关于它为什么在我的情况下不起作用的线索。

Answer 1

您无法将枚举注册为qml类型。 qmlRegisterType<T>()函数仅适用于从QObject派生的类。 AFAIK注册enumus不是必需的。他们被视为正常的整体。

为了能够将QObject中QVariant以内未导出的所有其他类型传递给qml，请使用qRegisterMetaType<T>。你不能直接在qml中使用它们，但你可以传递给C ++槽，属性和可调用的方法。

Answer 2

你可能没有正确地这样做。您需要注册包含枚举的类，然后它将自动可用。以下是一般情况的示例：

class MyClass : public QObject
{
    Q_OBJECT
    Q_ENUMS(MyEnum)
    Q_PROPERTY(MyEnum myEnum READ myEnum)

public:
    enum MyEnum {
        Value1 = 0,
        Value2
    };

    explicit MyObject(QObject *parent = 0);

    MyEnum myEnum() const;

    Q_INVOKABLE MyEnum getMyEnum() const;
};

qmlRegisterType<MyClass>("myclass", 1, 0, "MyClass");

要根据您的具体情况进行解释，您可能会写下这样的内容：

qmlRegisterType<Holiday>("holiday", 1, 0, "Holiday");

然后，您将从QML访问枚举值，如下所示：

holiday.Transportation

使用QML导出QFlags（Qt 5） - 使用staticMetaObject出错

2 个答案: