Error "use of undeclared identifier 'qmlRegisterType'"

[stereomatching]

The compiler always complain "use of undeclared identifier 'qmlRegisterType'"
Weird, but I can't find out why

.pro

@
QT += qml quick

SOURCES +=
main.cpp
fileReader.cpp

HEADERS +=
fileReader.hpp

@

fileReader.hpp

@
#ifndef FILEREADER_HPP
#define FILEREADER_HPP

#include <QObject>

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

Q_INVOKABLE QString read_file(QString const &fileName);

};

#endif // FILEREADER_HPP
@

fileReader.cpp

@
#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QTextStream>

#include "fileReader.hpp"

FileReader::FileReader(QObject *parent) :
QObject(parent)
{
}

QString FileReader::read_file(QString const &fileName)
{
QString content;
QFile file(fileName);
if (file.open(QIODevice::ReadOnly)) {
QTextStream stream(&file);
content = stream.readAll();
}
return content;
}
@

main.cpp

@
#include <QtQuick/QQuickView>
#include <QGuiApplication>

#include "fileReader.hpp"

int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);

qmlRegisterType<FileReader>("File", 1, 0, "FileReader");

return app.exec(&#41;;

}

@

Almost same as the example of PieChart, the weird thing is
the codes work under the PieChart example but can't work under
the new project I open

compiler : clang 3.2
os : mac osx 10.8.3
Qt: 5.1Beta

[Guigui]

qmlRegisterType() is defined in the QQmlEngine class.

Try adding @#include <QQmlEngine>@

[stereomatching]

added in main.cpp

@
#include <QtQuick/QQuickView>
#include <QGuiApplication>
#include <QQmlEngine>

#include "fileReader.hpp"

int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);

qmlRegisterType<FileReader>("File", 1, 0, "FileReader");

return app.exec(&#41;;

}

@

pop out same error message(exactly, I tried it before)

[SGaist]

Hi,

Isn't qmlRegisterType declared in QDeclarativeEngine ?

[Guigui]

It depends on the Qt version you're using.

According to "this":http://qt-project.org/doc/qt-5.0/qtquick/qtquick-porting-qt5.html#c-code document:

• QDeclarativeEngine for Qt 4.7/4.8
• QQmlEngine for Qt 5

Should be QQmlEngine in this case.

[stereomatching]

After adding "#include <QtDeclarative/QDeclarativeEngine>" into the main.cpp, can't work either.

Edit:
I found the problem, I should include
"#include <QtQuick/QQuickPaintedItem>"
Else the codes can not compile, I didn't expect this is needed
for qmlRegisterType, is this a correct solution?Is this a bug?
Qt team forget to include some headers?

[stefan0x53]

This is still valid in 5.2
However, I found that implementation lies in "qqml.h" header.
I added both to be on the safe side:
@#include <QtQml/QQmlEngine>
#include <qqml.h>@

[soleyla]

...and also valid in 5.3

I couldn't solve the problem by including QDeclarativeEngine or QQmlEngine, although I added declarative and qml to my .pro-file. Including QQuickPaintedItem or QQuickItem solved the problem. In the end I decided to add

@#include <QtQml>@

[beanhead]

as soleyla suggested, I tried:
@#include <QtQml>@

For me, this worked without having to make any of the other changes listed above in the previous posts...

[jeremy_k]

[quote author="beanhead" date="1411234589"]as soleyla suggested, I tried:
@#include <QtQml>@

For me, this worked without having to make any of the other changes listed above in the previous posts...[/quote]

That's the intended route.

The documentation is confusing. The various incarnations of qmlRegisterType are documented as related non-members of QQmlEngine (For Qt 5.3 anyway). Searching and then scrolling to the top of the page leads to the impression that <QQmlEngine> in the correct header file.

Some of the qmlRegister* function documentation snippets do mention including <QtQml>. It is easy to overlook, and violates the usual pattern.