Connecting a children widget with main widget

blixs

Can I have define those slots in the prototype of mainwindow and access them from the children widget?

andre

Children widget? What widget would that be?

What do you mean by "access"? Call them? Sure, if your "Children widget" has a reference to the mainwindow and the slots are active, you can call them. But I doubt that is what you are after.

If your "children widget" is the widget responsible for the drawing, you probably want to define the slot(s) on that widget directly. Then, you can connect the signal from your buttons (or button group) to that slot or those slots from the mainwidget's constructor.

blixs

Yeah, children widget is the canvas widget.

So I should define the slots directly there. Will not be a problem even the actions come from the MainWindow_ui?

goetz

You define the slots in the class that will do the drawing.

You only can define slots in UI components that have a C++ class on its own, not on widgets that are just child widgets of some other UI.

tekblom

Hi,
I am colloborating with blixs. Thanks for your answers, wanted to make it a bit clearer...

This is in our ui_mainwindow.h
@ void setupUi(QMainWindow *MainWindow)
{...
actionLinea = new QAction(MainWindow);
...
centralWidget = new PanelDibujo(MainWindow);
...
QObject::connect(actionLinea, SIGNAL(hovered()), centralWidget, SLOT(linea()));
}@

And should trigger in our childwidget paneldibujo.cpp
@void PanelDibujo::linea()
{
lineaMarked = true;
}@

But nothing happens...
It works with SLOT-methods like hide() etc...

giesbert

is linea() declared as slot?
Did you check debugging output if there are errors / warnings?

tekblom

No, it is not declared as a slot. You need to do that somewhere?

goetz

What does the console output show? Any errors about connections?

It should work too, if you declare linea() with the "public/protected/private slots" pseudo keyword.

goetz

[quote author="tekblom" date="1295269403"]No, it is not declared as a slot. You need to do that somewhere?[/quote]

Yes, you must add that in the class definition (usually in a .h file). See the "Signals & Slots":http://doc.qt.nokia.com/stable/signalsandslots.html docs for some examples. Unfortunately the docs say it not clear enough, that you must add the "public/protected/private slots" keywords.

tekblom

Oh, yeah I found it now.

Object::connect: No such slot PanelDibujo::linea() in ./ui_mainwindow.h:109
Object::connect: (sender name: 'actionLinea')
Object::connect: (receiver name: 'centralWidget')

I added in paneldibujo.h
@ public slots:
void linea();@

and the error disappeared but still nothings happens. Use the same code as before...

But now...Wow it works ;)
Had to rebuild it some times!

Thanks for the help!

goetz

You should at least call qmake after you add the first signal or slot to your class to catch up the changes.