signal is not working

[frnklu20]

Hi,

DiagramScene.h

class DiagramScene : public QGraphicsScene
{
    Q_OBJECT
...
signals:
    void itemInserted(DiagramItem *item);
    void textInserted(QGraphicsTextItem *item);
    void clicked();
    void addtreeitem(DiagramItem *item);//here is the signal
....
};

that's it

How can i write it with the new sintax?
When i execute the program it says "QObject::connect: No such signal DiagramScene::addtreeitem(DiagramItem*);"

PS: i changed the input of the signal and the slot to only DiagramItem*

[Christian Ehrlicher]

@frnklu20 said in signal is not working:

SIGNAL(addtreeitem(QIcon, DiagramItem*);

I don't see such a signal in your header (apart from the fact that the semicolon is absolutely wrong there). As already wrote above: Use the new signal/slot syntax or properly check the return value of QObject::connect() / take a look at the console output during runtime and you will notice that there is no such a signal at all.

/edit: did not saw you last comment about the change of the signal, but the rest of my comments is still valid.

[frnklu20]

but how can i write it in the new sintax?

[Christian Ehrlicher]

@frnklu20 said in signal is not working:

but how can i write it in the new sintax?

By looking into the documentation

[frnklu20]

connect(scene, &DiagramScene::addtreeitem),
            this, &MainWindow::handleaddtreeitem);

it gives me an error in addtreeitem, it says" error: no matching member function for call to 'connect'"

[SGaist]

You are missing the & for the function parameters.

[frnklu20]

yeah i fixed it! but it gives me an error in the connect

if i put the &parameter in the objects it says cannot take the adress of an rvalue of type MainWindow and no matching member function for call to 'connect'

[SGaist]

And what error exactly ?

[frnklu20]

in the no matching member it says:
mainwindow.cpp:25:5: error: no matching member function for call to 'connect'
qobject.h:228:43: note: candidate function template not viable: requires at least 4 arguments, but 2 were provided
qobject.h:260:13: note: candidate function template not viable: requires 3 arguments, but 2 were provided
qobject.h:269:13: note: candidate function template not viable: requires at least 4 arguments, but 2 were provided
qobject.h:300:13: note: candidate function template not viable: requires 3 arguments, but 2 were provided
qobject.h:308:13: note: candidate function template not viable: requires at least 4 arguments, but 2 were provided
qobject.h:463:41: note: candidate function not viable: requires at least 3 arguments, but 2 were provided
qobject.h:208:36: note: candidate function not viable: requires at least 4 arguments, but 2 were provided
qobject.h:211:36: note: candidate function not viable: requires at least 4 arguments, but 2 were provided

don't know what that means

[Christian Ehrlicher]

Since you're doing the connect in a class which is not derived from QObject or in main() you have forgot 'QObject::' before connect since it's a static function of QObject

And you've a syntax error in your code - '&DiagramScene::addtreeitem),'

[jsulm]

@frnklu20 Don't put & in front of "this" - "this" is already a pointer. Currently you're passing pointer to pointer which is wrong here.

[Pl45m4]

This post is deleted!