Question

我有以下C ++自定义对象，希望在QML中用作enum类型：

#include <QtQml>
#include <QApplication>
#include <QQmlApplicationEngine>

#include "database/uepeoplemodel.h"
#include "core/uestatus.h"
#include "core/uedatabaseconnectionstatus.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QQmlApplicationEngine engine;

    UeStatus* ueApplicationStatus=new UeStatus(qApp);
    UePeopleModel* uePeopleModel=new UePeopleModel(qApp);

    QObject::connect(uePeopleModel,
                     SIGNAL(ueSignalDatabaseConnectionChanged(UeDatabaseConnectionStatus::UeTypeDatabaseConnectionStatus)),
                     ueApplicationStatus,
                     SLOT(ueSignalDatabaseConnectionChanged(UeDatabaseConnectionStatus::UeTypeDatabaseConnectionStatus)));

    uePeopleModel->ueConnectToDatabase();

    engine.rootContext()->setContextProperty("uePeopleModel",
                                             uePeopleModel);
    engine.rootContext()->setContextProperty("ueApplicationStatus",
                                             ueApplicationStatus);
    engine.addImageProvider(QLatin1String("uePeopleModel"),
                            uePeopleModel);

    qmlRegisterUncreatableType<UeDatabaseConnectionStatus::UeTypeDatabaseConnectionStatus>("si.mikroelektronika",
                                                                                           1,
                                                                                           0,
                                                                                           "UeTypeDatabaseConnectionStatus",
                                                                                           "Database Connection Status");

    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

    return app.exec();
}

我遇到编译错误（使用gcc version 4.9.2上的Linux work002 3.19.0-28-generic #30-Ubuntu SMP Mon Aug 31 15:52:51 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux：

包含来自的文件 /opt/QtOpenSource55/5.5/gcc_64/include/QtCore/qobject.h:40:0，来自/opt/QtOpenSource55/5.5/gcc_64/include/QtCore/qabstractanimation.h:37，来自/opt/QtOpenSource55/5.5/gcc_64/include/QtCore/QtCore:4, 来自/opt/QtOpenSource55/5.5/gcc_64/include/QtQml/QtQmlDepends：3，来自/opt/QtOpenSource55/5.5/gcc_64/include/QtQml/QtQml:3, from ../ueBlagajnaClient/main.cpp:1:/opt/QtOpenSource55/5.5/gcc_64/include/QtCore/qobjectdefs.h:88:5：错误：类定义可能不会被声明为朋友朋友Q_DECL_CONSTEXPR const QMetaObject * qt_getEnumMetaObject（ENUM）Q_DECL_NOEXCEPT {return＆amp; staticMetaObject; } \ ^ ../ueBlagajnaClient/database/../core/uedatabaseconnectionstatus.h:17:5：注意：在扩展宏观＆＃39; Q_ENUM＆＃39; Q_ENUM（UeTypeDatabaseConnectionStatus） ^ /opt/QtOpenSource55/5.5/gcc_64/include/QtCore/qobjectdefs.h:88:35：错误：＆＃39; QMetaObject＆＃39;既不是功能也不是会员功能;不能被宣布为朋友朋友Q_DECL_CONSTEXPR const QMetaObject * qt_getEnumMetaObject（ENUM）Q_DECL_NOEXCEPT {return＆amp; staticMetaObject; } \ ^ ../ueBlagajnaClient/database/../core/uedatabaseconnectionstatus.h:17:5：注意：在扩展宏观＆＃39; Q_ENUM＆＃39; Q_ENUM（UeTypeDatabaseConnectionStatus） ^ /opt/QtOpenSource55/5.5/gcc_64/include/QtCore/qobjectdefs.h:88:35：错误：预期＆＃39;;＆＃39;在会员声明结束时朋友Q_DECL_CONSTEXPR const QMetaObject * qt_getEnumMetaObject（ENUM）Q_DECL_NOEXCEPT {return＆amp; staticMetaObject; } \ ^ ../ueBlagajnaClient/database/../core/uedatabaseconnectionstatus.h:17:5：注意：在扩展宏观＆＃39; Q_ENUM＆＃39; Q_ENUM（UeTypeDatabaseConnectionStatus） ^ /opt/QtOpenSource55/5.5/gcc_64/include/QtCore/qobjectdefs.h:88:73：错误：ISO C ++禁止声明＆＃39; qt_getEnumMetaObject＆＃39;没有输入[-fpermissive] 朋友Q_DECL_CONSTEXPR const QMetaObject qt_getEnumMetaObject（ENUM）Q_DECL_NOEXCEPT {return＆amp; staticMetaObject; } \ ^ ../ueBlagajnaClient/database/../core/uedatabaseconnectionstatus.h:17:5：注意：在扩展宏观＆＃39; Q_ENUM＆＃39; Q_ENUM（UeTypeDatabaseConnectionStatus） ^ ../ueBlagajnaClient/database/../core/uedatabaseconnectionstatus.h：In 成员函数＆＃39; int UeDatabaseConnectionStatus :: qt_getEnumMetaObject（UeDatabaseConnectionStatus :: UeTypeDatabaseConnectionStatus）＆＃39 ;: /opt/QtOpenSource55/5.5/gcc_64/include/QtCore/qobjectdefs.h:88:101：错误：无法转换＆＃39; const QMetaObject *＆＃39;到＆＃39; int *＆＃39;作为回报朋友Q_DECL_CONSTEXPR const QMetaObject qt_getEnumMetaObject（ENUM）Q_DECL_NOEXCEPT {return＆amp; staticMetaObject; } \ ^ ../ueBlagajnaClient/database/../core/uedatabaseconnectionstatus.h:17:5：注意：在扩展宏观＆＃39; Q_ENUM＆＃39; Q_ENUM（UeTypeDatabaseConnectionStatus） ^在/opt/QtOpenSource55/5.5/gcc_64/include/QtQml/QtQml:9:0中包含的文件中， from ../ueBlagajnaClient/main.cpp:1:/opt/QtOpenSource55/5.5/gcc_64/include/QtQml/qqml.h：在实例化中＆＃39; int qmlRegisterUncreatableType（const char ，int，int，const char *， const QString＆amp;）[与T = UeDatabaseConnectionStatus :: UeTypeDatabaseConnectionStatus]＆＃39 ;: ../ueBlagajnaClient/main.cpp:35:120：从这里要求 /opt/QtOpenSource55/5.5/gcc_64/include/QtQml/qqml.h:83:59：错误：＆＃39; staticMetaObject＆＃39;不是会员＆＃39; UeDatabaseConnectionStatus :: UeTypeDatabaseConnectionStatus＆＃39; const char * className = T :: staticMetaObject.className（）; \ ^ /opt/QtOpenSource55/5.5/gcc_64/include/QtQml/qqml.h:134:5：注意：在扩大宏观＆＃39; QML_GETTYPENAMES＆＃39; QML_GETTYPENAMES ^在/opt/QtOpenSource55/5.5/gcc_64/include/QtQml/QtQml:9:0中包含的文件中， from ../ueBlagajnaClient/main.cpp:1:/opt/QtOpenSource55/5.5/gcc_64/include/QtQml/qqml.h:144:51：错误：＆＃39; staticMetaObject＆＃39;不是会员＆＃39; UeDatabaseConnectionStatus :: UeTypeDatabaseConnectionStatus＆＃39; uri，versionMajor，versionMinor，qmlName，＆amp; T :: staticMetaObject， ^ Makefile：1319：目标＆＃39; main.o＆＃39;的配方失败了：*** [main.o]错误1 08:04:15：过程＆＃34; / usr / bin / make＆＃34;退出代码2.错误时构建/部署项目ueBlagajnaClient（套件：Desktop Qt 5.5.0 GCC 64位）执行步骤＆＃34;制作＆＃34;

为什么以及如何摆脱这个错误？我如何滥用方法qmlRegisterUncreatableType？

Answer 1

如果您要使用qmlRegisterType，则使用的类必须是继承QObject且具有Q_OBJECT宏的类：

class UeTypeDatabaseConnectionStatus: public QObject
{
    Q_OBJECT

public:
    enum StatusEnum
    {
        NOT_CONNECTED=false,
        CONNECTED=true
    }
    Q_ENUM(StatusEnum)
    ...
}

在QML中，您可以创建它的实例，就像使用任何其他QML类一样。

编辑：但是，由于您只想使用枚举值，因此请使用qmlRegisterUncreatableType。这样就可以注册类型，但是你无法创建它的实例。

要访问枚举值，请导入类型并像使用任何其他枚举一样使用它：

connectionProperty: UeTypeDatabaseConnectionStatus.CONNECTED;

将c ++自定义类型暴露给QML

1 个答案: