Qt metaObject->indexOfMethod always return -1

Question

I have one function declared in Foo class:

Q_INVOKABLE void setImageUrl(const QString &imageUrl);

However I cannot get the function index of that method:

Foo* foo = new Foo();
const QMetaObject* metaObject = foo->metaObject();
QString functionNameWithparameter("setImageUrl(QString)");
int functionIndex = metaObject->indexOfMethod(functionNameWithParameter.toStdString().c_str());

if (functionIndex >= 0) {
 // never the case
}

What am I missing?

Answer 1

Apart from the two compiler errors, your approach seems to be correct. I assume that you had some changes that required to rerun moc, but you have not actually done so. This is the working code for me.

main.cpp

#include <QMetaObject>
#include <QDebug>
#include <QString>

class Foo : public QObject
{
    Q_OBJECT
    public:
        explicit Foo(QObject *parent = Q_NULLPTR) : QObject(parent) {}
    Q_INVOKABLE void setImageUrl(const QString &) {}
};

#include "main.moc"

int main()
{
    Foo* foo = new Foo();
    const QMetaObject* metaObject = foo->metaObject();
    QString functionNameWithParameter("setImageUrl(QString)");
    qDebug() << metaObject->indexOfMethod(functionNameWithParameter.toStdString().c_str());
    return 0;
}

main.pro

TEMPLATE = app
TARGET = main
QT = core
CONFIG += c++11
SOURCES += main.cpp

Build and Run

qmake && make && ./main

Output

5