The Famous 'QMetaProperty::read: Unable to handle unregistered datatype' error

LonniB

Hello everyone,

For starters, I'm fairly new to Qt and QML and still just an intern in my firm, so please accept my apologies if I am asking dumb questions.

Ok so here I go with my problem. I'm having the QMetaProperty::read: Unable to handle unregistered datatype error with my example. I am basically just re-coding myself the mine hunt program example. And here's the thing, whether I launch my own code or the one provided online for that I get @QMetaProperty::read: Unable to handle unregistered datatype 'QDeclarativeListProperty<Tile>' for property 'MineSweeperGame::tiles'@

Here's my code:

main.cpp :
@#include <QtGui/QGuiApplication>
#include <QApplication>
#include <QtDeclarative/QDeclarativeView>
#include <QtDeclarative/QDeclarativeContext>
#include <QtDeclarative/QDeclarativeEngine>
#include <QtQuick/QQuickPaintedItem>

#include "qtquick2applicationviewer.h"
#include "minesweepergame.h"

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

QApplication app(argc, argv);
QDeclarativeView canvas;

qRegisterMetaType<Tile>("Tile");

MineSweeperGame* g = new MineSweeperGame();

#ifdef Q_OS_SYMBIAN
canvas.setResizeMode(QDeclarativeView::SizeRootObjectToView);
#endif
canvas.engine()->rootContext()->setContextObject(g);
canvas.setSource(QString("../Resources/qml/MyMineSweeper/main.qml"));
QObject::connect(canvas.engine(), SIGNAL(quit()), &app, SLOT(quit()));

#ifdef Q_OS_SYMBIAN
canvas.showFullScreen();
#else
canvas.setGeometry(QRect(100, 100, 450, 450));
canvas.show();
#endif

return app.exec();

}
@

tile.h :
@#ifndef TILE_H
#define TILE_H
#include <QObject>
#include <QMetaType>

class Tile : public QObject
{
Q_OBJECT
private:

bool _flipped ;
bool _hasMine ;
bool _hasFlag ;
int _nbMines ;

public:
Tile():_flipped(false), _hasMine(false), _hasFlag(false), _nbMines(-1) {}

Tile(const Tile &other):_flipped(other._flipped), _hasMine(other._hasMine), _hasFlag(other._hasFlag), _nbMines(other._nbMines){}

~Tile(){}

Q_PROPERTY(bool flipped READ flipped WRITE setFlipped NOTIFY flippedChanged)
bool flipped();
void setFlipped(bool b);

Q_PROPERTY(bool hasMine READ hasMine WRITE setHasMine NOTIFY hasMineChanged)
bool hasMine();
void setHasMine(bool b);

Q_PROPERTY(bool hasFlag READ hasFlag WRITE setHasFlag NOTIFY hasFlagChanged)
bool hasFlag();
void setHasFlag(bool b);

Q_PROPERTY(int nbMines READ nbMines WRITE setNbMines NOTIFY nbMinesChanged)
int nbMines();
void setNbMines(int nb);

signals:
void flippedChanged();
void hasMineChanged();
void hasFlagChanged();
void nbMinesChanged();

};
Q_DECLARE_METATYPE(Tile)
#endif // TILE_H
@

MineSweeper.h :
@#ifndef MINESWEEPERGAME_H
#define MINESWEEPERGAME_H

#include <tile.h>

#include <QObject>
#include <QList>
#include <QDeclarativeListProperty>

class MineSweeperGame : public QObject{

Q_OBJECT

private:
bool onBoard(int row, int col) const;

Tile* tile(int row, int col);

int getHint(int row, int col);

void setPlaying(bool b);

QList<Tile *> _tiles ;
int numCols ;
int numRows ;
bool playing ;
bool won ;
int remaining ;
int nMines ;
int nFlags ;

public:
MineSweeperGame();

Q_PROPERTY(QDeclarativeListProperty<Tile> tiles READ tiles CONSTANT)
QDeclarativeListProperty<Tile> tiles();

Q_PROPERTY(bool isPlaying READ isPlaying NOTIFY hasPlayingChanged)
bool isPlaying()  {return playing;}

Q_PROPERTY(bool hasWon READ hasWon NOTIFY hasWonChanged)
bool hasWon()  {return won;}

Q_PROPERTY(int numMines READ numMines NOTIFY numMinesChanged)
int numMines() const {return nMines;}

Q_PROPERTY(int numFlags READ numFlags NOTIFY numFlagsChanged)
int numFlags() const {return nFlags;}

public slots:
Q_INVOKABLE bool flip(int row, int col);
Q_INVOKABLE bool flag(int row, int col);
void setBoard();
void reset();

signals:
void hasPlayingChanged();
void hasWonChanged();
void numMinesChanged();
void numFlagsChanged();
};

#endif // MINESWEEPERGAME_H
@

tile.cpp :
@#include "tile.h"

bool Tile::flipped(){
return _flipped ;
}

void Tile::setFlipped(bool b){
if (_flipped == b){
return ;
}
_flipped = b ;
emit flippedChanged();
}

bool Tile::hasMine(){
return _hasMine ;
}

void Tile::setHasMine(bool b){
if(_hasMine==b){
return ;
}
_hasMine = b ;
emit hasMineChanged();
}

bool Tile::hasFlag(){
return _hasFlag ;
}

void Tile::setHasFlag(bool b){
if(_hasFlag==b){
return ;
}
_hasFlag = b ;
emit hasFlagChanged();
}

int Tile::nbMines(){
return _nbMines ;
}

void Tile::setNbMines(int nb){
if(_nbMines == nb){
return ;
}
_nbMines = nb ;
emit nbMinesChanged();
}

@

Since the QML code is not complete there is no point in giving them to ya now.
Thanks in advance.

Cheers,

LB

stevenceuppens

Hi,

Do you register "Tile" with the QML type system via qmlRegisterType()?

LonniB

Yes I did. I tried with qRegisterType<Tile>() and qRegisterType<Tile>("Tile") in my main.cpp. Does not work :(

stevenceuppens

And also with:

qmlRegisterType<Tile>("Tile");

instead of

qRegisterMetaType<Tile>("Tile");

:)

LonniB

Well it seems that qmlRegisterType<Tile>("Tile") is not a valid function call.
However I tried qmlRegisterType<Tile>() and I do get the exact same error ><

LonniB

In case you find it easier to have my whole code here it goes : "https://dl.dropboxusercontent.com/u/30965278/MyMineSweeper.zip":https://dl.dropboxusercontent.com/u/30965278/MyMineSweeper.zip

LonniB

Up :)

chrisadams

Please see the documentation for the qmlRegisterType function at http://qt-project.org/doc/qt-5/qqmlengine.html#qmlRegisterType

You need to call it like:

@
qmlRegisterType<Tile>("com.your.namespace", 1, 0, "Tile");
@

Then, the code which uses that Tile type within QML needs to ensure that it does

@
import com.your.namespace 1.0
@

in order to have access to that type information.

Cheers,
Chris.

LonniB

Alright i will try to do that !
However, I am not using a namespace therefore I don't know if that is really relevent is it?