CODEWITHSUNDEEP
c++qtenumssignals-slots
Niklas
Niklas

Reputation: 25413

Qt own enum in class

I want to declare my own enum in a class in Qt and use it for signals and slots, but I get this error.

QObject::connect: Cannot queue arguments of type 'ClassA::MyEnum'
(Make sure 'ClassA::MyEnum' is registered using qRegisterMetaType().)

This is my source code:

ClassA.h

public:
    enum MyEnum {
        READING = 0,
        STOPPED = 1,
        FINISHED = 2
    };

signals:
    void changed(QString text, int readTextInPercent, ClassA::MyEnum status);

ClassA.cpp

emit changed(QString("string"), 50, ClassA::READING);

ClassB.h

public slots:
    void changed(QString text, int readTextInPercent, ClassA::MyEnum status);

ClassB.cpp

this->connect(m_ClassA, SIGNAL(changed(QString, int, ClassA::MyEnum)), this, SLOT(changed(QString, int, ClassA::MyEnum)));

void ClassB::changed(QString text, int readTextInPercent, ClassA::MyEnum status) {

}

I don't know where and with which parameter I have to put the qRegisterMetaType.

Upvotes: 3

Views: 4051

Answers (3)

parsley72
parsley72

Reputation: 9087

You can avoid having to call Q_DECLARE_METATYPE and qRegisterMetaType() by using Q_ENUM, which was added in Qt 5.5:

public:
    enum MyEnum {
        READING = 0,
        STOPPED = 1,
        FINISHED = 2
    };
    Q_ENUM(MyEnum)

Upvotes: 2

piponazo
piponazo

Reputation: 488

The error thrown by Qt is very descriptive:

Make sure 'ClassA::MyEnum' is registered using qRegisterMetaType()

So you will need to include this line:

qRegisterMetaType<ClassA::MyEnum>("ClassA::MyEnum");

In any part of your code in which you know it will be called. I use to include the qRegisterMetaType in the main function of my applications. I recommend you to take a look to the Qt Documentation about the topics: qRegisterMetaType & Q_DECLARE_METATYPE.

Upvotes: 4

user1551592
user1551592

Reputation:

You have to do:

Q_DECLARE_METATYPE(ClassA::MyEnum)

in your classA.h header.

Then in ClassA constructor (or main() but remember to include classa.h there first):

qRegisterMetaType<ClassA::MyEnum>("ClassA::MyEnum");

Then use like:

connect(whatever, SIGNAL(whatever_uses_myenum(ClassA::MyEnum)), ..., ...)

Upvotes: 7

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