After adding the QAction
to the menu, you only have to connect QMenu
to the slot. You don't connect each action individually to the slot:
for(int j=0; j<channelTypes[i].getNumChannels() ; j++){
ch_name = <name from the database for the channel j>;
QAction *subMenuAct = subMenu->addAction(tr(ch_name));
subMenuAct->setData(ch_name);
}
connect(subMenu, SIGNAL(triggered(QAction *)),
this, SLOT(playChannel(QAction *)), Qt::UniqueConnection);
As I don't know how you if you delete subMenu
each time the dynamic menu is filled, the Qt::UniqueConnection
ensure that the slot won't be reconnected multiple times.
For the signal mapper version, you should only connect the actions to the mapper in the loop. The connection from the mapper to the slot should only be done once.
for(int j=0; j<channelTypes[i].getNumChannels() ; j++){
ch_name = <name from the database for the channel j>;
QAction *subMenuAct = subMenu->addAction(tr(ch_name));
connect(subMenuAct, SIGNAL(triggered()), signalMapper, SLOT(map()));
signalMapper->setMapping(subMenuAct, ch_name);
}
connect(signalMapper, SIGNAL(mapped(QString)), this, SLOT(playChannel(QString)));
And for that case, the slot playChannel
should accept a QString
instead of a QAction*
.