Using QAction::setData , in order to pass my own defined object , can not get the object

stabber

In my project , we must pass our own defined object when menu clicked.

this is demo code:
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#include "customdefinedemo.h"
#include "qnewitem.h"

Q_DECLARE_METATYPE(QNewItem)

customDefineDemo::customDefineDemo(QWidget *parent, Qt::WFlags flags)
: QMainWindow(parent, flags)
{
ui.setupUi(this);
connect(ui.pushButton , SIGNAL(clicked()),this,SLOT(onBtnClick()));
}

customDefineDemo::~customDefineDemo()
{

}

void customDefineDemo::onBtnClick()
{
QMenu* pMenu = new QMenu();
QNewItem* pNewItem = new QNewItem();
qint16 nAge = 34;
QVariant qv;
do
{
QAction* pPortraitView = new QAction(tr("New"), this);
QAction* pAddGroup = new QAction(tr("Open"), this);
QAction* pDeleteGroup = new QAction(tr("Save"), this);

pNewItem->setUserInfo(tr("Eric"),nAge);

pPortraitView->setData( QVariant::fromValue((QObject*)pNewItem) ) ;

connect(pPortraitView,SIGNAL(triggered()),this,SLOT(triggeredMenuSendMsgContact()));

pMenu->addAction(pPortraitView);
pMenu->addAction(pAddGroup);
pMenu->addAction(pDeleteGroup);
pMenu->exec(QCursor::pos());
} while (false);
delete pMenu;
}

void customDefineDemo::triggeredMenuSendMsgContact()
{
QAction* pSendMsg= NULL;
QNewItem* pObj = NULL;
do
{
pSendMsg=qobject_cast<QAction*>(sender());

*pObj = pSendMsg->data().value<QNewItem>();
} while (false);
}
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QNewItem class is own defined , I wanna pass it when menu clicked,but I can not get it ! Where is error? thanx

dmcr

Please use the code tags for a better visibility....
Also is this really related with QML ?

lgeyer

Either <code>QNewItem</code> inherits <code>QObject</code> in which case <code>Q_DECLARE_METATYPE(QNewItem)</code> is wrong, because the type is non-copyable or <code>QNewItem</code> does not inherit <code>QObject</code> in which case the cast to <code>QObject*</code> is wrong (do not use C-style casts in C++).

Generally you set a <code>QVariant</code> containing a <code>QObject*</code>, expect to get a <code>QVariant</code> containing a <code>QNewItem</code> and try to copy-construct it in a <code>nullptr QNewItem</code> object; this isn't going to happen.

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class QNewItem : public QObject { ... };

Q_DECLARE_METATYPE(QNewItem*)

pPortraitView->setData(QVariant::fromValue(pNewItem));

pObj = pSendMsg->data().value<QNewItem*>();
delete pObj;
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