QML 组件枚举 class 属性

Question

我在单独的 qml 文件中有委托组件，我想在其中有一个属性是一个 enum class 类型 来自 来自 c++ QObject。这可能吗？

这是一个最小（非）工作示例：

card.h

#include <QObject>

class Card : public QObject
{
    Q_OBJECT
public:
    explicit Card(QObject *parent = 0);

    enum class InGameState {
        IDLE,
        FLIPPED,
        HIDDEN
    };
    Q_ENUM(InGameState)

private:
    InGameState mState;
};
Q_DECLARE_METATYPE(Card::InGameState)

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include "card.h"
int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    qmlRegisterType<Card::InGameState>("com.memorygame.ingamestate", 1, 0, "InGameState");
    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

    return app.exec();
}

testcard.qml

import QtQuick 2.0
import com.memorygame.ingamestate 1.0

Item {
    property InGameState state

    Rectangle {
        id: dummy
        width: 10
    }
}

我得到的编译器错误：

D:\Programs\Qt\Qt5.7.0.7\mingw53_32\include\QtQml\qqml.h:89: error: 'staticMetaObject' is not a member of 'Card::InGameState' const char *className = T::staticMetaObject.className(); \

枚举 class 不是 QObject，这就是我收到此错误的原因，对吧？但是 Q_ENUM 宏不应该让它在 MetaSystem 中可用吗？

你能帮我解决这个问题吗？我可以删除枚举 class，并将其更改为枚举，并在 qml 中使用 int 属性，但我想使用 c++11 功能。

Answer 1

根据 documentation,

To use a custom enumeration as a data type, its class must be registered and the enumeration must also be declared with Q_ENUM() to register it with Qt's meta object system.

所以你需要注册你的 class Card 而不是枚举 InGameState:

qmlRegisterType<Card>("com.memorygame.card", 1, 0, "Card");

Additionally:

The enumeration type is a representation of a C++ enum type. It is not possible to refer to the enumeration type in QML itself; instead, the int or var types can be used when referring to enumeration values from QML code.

例如，在您的情况下，枚举应按如下方式使用：

import QtQuick 2.0
import com.memorygame.card 1.0

Item {
    property int state: Card.FLIPPED

    Rectangle {
        id: dummy
        width: 10
    }
}

QML 组件枚举 class 属性

QML component enum class property

qt

qml

c++11

enum-class