Help with sender() analysis

Anonymous_Banned275

I am trying to use sender() to find the actual "index" which triggered the connect.
I looked at the "RX_object" and see lot of info there but cannot find "index"..
The parameters pased to SLOT are max values , not actual "index".
Many thanks for help.

connect(subMenu_checkableActionInMenu[index] ,
        &QAction::triggered, this ,[=]() { this->processAction(index_sub,index) ;});

QObject  *RX_object = sender();

Axel Spoerl

@AnneRanch
You won't find the index there.
sender()is a QObject, which in your case is either a QMenuor a QAction.
If the sender of a signal needs to know certain properties, you can use setProperty, to store information and read it in the slot, see here.

Anonymous_Banned275

@Axel-Spoerl per doc

Advanced Signals and Slots Usage

For cases where you may require information on the sender of the signal, Qt provides the QObject::sender() function, which returns a pointer to the object that sent the signal.

so
how do I get that pointer ?
QObject *RX_object = sender(); ?

and when I get it should it contain the "index" ?

Pl45m4

@AnneRanch said in Help with sender() analysis:

and when I get it should it contain the "index" ?

No, it will never contain your index, because you added the structure of QMenu- and QAction-items. The single QActions don't know about any index or what you've built around, so does their base class QObject not know.
The index of the signal emitting widget in your container is neither transmitted nor can be somehow extracted from the sender() QObject.

If you need the container index of your sender item in your slot, there is, for sure, a better solution to do what you want to do.

JonB

@AnneRanch
sender() will in no way help you, and should be avoided.

There are just two ways to pass values (like index_sub or index) from where you do the connect() to a slot connected to the signal:

Write the slot as a lambda, as we have discussed, just as your

connect(subMenu_checkableActionInMenu[index] ,
        &QAction::triggered, this ,[=]() { this->processAction(index_sub,index) ;});

This, for example, passes the index as a parameter which is used in subMenu_checkableActionInMenu[index] that is the sender. So it is just what you are attemtping to get out of sender(). If you do not think that has the right value then there is something mixed up.

Add the value as a property to the sending object, as @Axel-Spoerl wrote earlier, and then use sender() to get that object and read the stored property in it. Which is a long and complicated way round compared to using a lambda.

Anonymous_Banned275

@JonB I do not think I said this - but the "index
passed is the index to LAST item in menu, NOT the current index which trigged the connect.
Yes , I must have something in code which is wrong , obviously ... I'll work on that.

JonB

@AnneRanch
All I can say is if you try something like:

// assume array has >= 3 elements
for (int index = 0; index < 3; index++)
    connect(subMenu_checkableActionInMenu[index], &QAction::triggered,
            this, [=]() { qDebug() << index; } );

I would expect you to see 0/1/2 according as which one you click on. You might like to test that.