Qt metaObject->indexOfMethod always return -1 - c++

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