Debug output when calling QToolBar::addAction()

Perdrix

I'm getting a debug output message:

QObject::connect: Use the SLOT or SIGNAL macro to connect DEditStars::dragButtonPressed

when I do:

    QToolBar t(&w);
    QIcon dragRect("C:/Users/amonra/Documents/GitHub/DSS/DeepSkyStacker/Buttons/ButtonSelect_Up.bmp");
    t.setOrientation(Qt::Vertical);
    t.addAction(dragRect, "", &editor, "dragButtonPressed");

clearly Qt doesn't love me a lot, but why?

JonB

@Perdrix said in Debug output when calling QToolBar::addAction():
Just to be 100% clear, and get you on the right track of new syntax so you will like it(!), as @Pl45m4 has said the whole line needs to be:

t.addAction(dragRect, "", &editor, &DEditStars::dragButtonPressed);

Page https://wiki.qt.io/New_Signal_Slot_Syntax gives you comparative examples.

Bonnie

because you didn't give it a slot, but a normal string...

Pl45m4

@Perdrix

Is DEditStars a QObject? Do you have Q_OBJECT macro in this class? Is your function dragButtonPressed a slot?

And dont put the function name in double quotes, like @Bonnie already said

https://doc.qt.io/qt-5/qtoolbar.html#addAction-3

Perdrix

Yes, yes and yes!

#include <QObject>
class DEditStars :
    public QObject
{
    Q_OBJECT

typedef QObject
        Inherited;

public:
    DEditStars() :
        QObject()
    {
    };

    virtual ~DEditStars() {};

public slots:
    void mousePressEvent(QMouseEvent* e);
    void mouseMoveEvent(QMouseEvent* e);
    void mouseReleaseEvent(QMouseEvent* e);

    void dragButtonPressed();

};

Don't put function name in "" ??? The function sig:

QAction *QToolBar::addAction(const QIcon &icon, const QString &text, const QObject *receiver, const char *member)

requires it to be in ""

David

JonB

@Perdrix

What type is your editor?
Do a delete of all files in your debug/release directory, and rebuild. Qt can get in a mess over its Q_OBJECT macros and other things, sometimes this happens and this fixes.
typedef QObject Inherited;: probably irrelevant, just wondering whether this could have any detrimental effect on moc etc.
dragButtonPressed is a slot of your own you have created?

Oh, you didn't make clear:

I'm getting a debug output message:

QObject::connect: Use the SLOT or SIGNAL macro to connect DEditStars::dragButtonPressed

At first I thought you meant at compile-time, now I'm thinking you mean at runtime when the addAction() is hit?

In any case please do the complete rebuild before going any further....

Perdrix

Editor is of type DEditStars as you might hope.

Never had a problem using that sort of typedef before.

Yes this is at RUNTIME when addAction is invoked (after a full cleanup and rebuild):

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QPixmap p("C:\\Users\\amonra\\Documents\\Astrophotography\\NGC 7789 Caroline's Rose or Herschel's Spiral Cluster\\NGC7789 Edited large.png");
    DSSImageWidget w(p);
    DEditStars editor;
    QObject::connect(&w, &DSSImageWidget::Image_mousePressEvent, &editor, &DEditStars::mousePressEvent);
    QToolBar t(&w);
    QIcon dragRect("C:/Users/amonra/Documents/GitHub/DSS/DeepSkyStacker/Buttons/ButtonSelect_Up.bmp");
    t.setOrientation(Qt::Vertical);
    t.addAction(dragRect, "", &editor, "dragButtonPressed()");
    //t.setFixedSize(50, 50);
    t.setIconSize(QSize(48, 48));
    w.setToolBar(&t);
    w.show();
    return a.exec();
}

Debug log snippet:

'DSSImageWidget.exe' (Win32): Loaded 'C:\Qt\5.15.0\msvc2019_64\plugins\imageformats\qwebpd.dll'. Symbols loaded.
QObject::connect: Use the SLOT or SIGNAL macro to connect DEditStars::dragButtonPressed()
'DSSImageWidget.exe' (Win32): Loaded 'C:\Windows\System32\d3d9.dll'.

JonB

@Perdrix

So editor is of type DEditStars and not DEditStars *, right?
I certainly would not expect it to work with "dragButtonPressed()", it would need to be "dragButtonPressed" as you showed originally.
(Temporarily) give up on this constructor. Create the action with an overload which does not take that, and set the signal/slot on the QAction's triggered after it is created. Can you get that to work?

P.S.
[signal]void QAction::triggered(bool checked = false)

Your problem may (well?) be that you need your dragButtonPressed() slot to be declared with that (optional) parameter, in order to match correctly?

jsulm

@Perdrix said in Debug output when calling QToolBar::addAction():

QObject::connect: Use the SLOT or SIGNAL macro to connect DEditStars::dragButtonPressed()

This tells you exactly what the problem is.
It should be:

t.addAction(dragRect, "", &editor, SLOT(dragButtonPressed()));

JonB

@jsulm
The OP is trying to use the following overload:

QAction *QToolBar::addAction(const QIcon &icon, const QString &text, const QObject *receiver, const char *member)

https://doc.qt.io/qt-5/qtoolbar.html#addAction-3

The action's triggered() signal is connected to member in receiver.

Note how the last argument is of type const char *, for the name of a member function.

jsulm

@JonB He still has to use SLOT, see https://doc.qt.io/qt-5/qobject.html#connect - it has char* also, but you have to use SLOT/SIGNAL macros, not just plain string containing slot/signal name.

JonB

@jsulm

but you have to use SLOT/SIGNAL macros, not just plain string containing slot name.

Ohhh, well that's not very clear from the docs: "the name of a member function" :) I took the docs as indicating as he did in his original post!

@Perdrix
So follow @jsulm's answer! Though TBH you would be far better getting rid of all SIGNAL/SLOT() macros/methods, and doing it new-style, as I say over & over in this forum :) Then the issue would not arise....

P.S.
That would be template <typename Functor> QAction *QToolBar::addAction(const QIcon &icon, const QString &text, const QObject *context, Functor functor), overload https://doc.qt.io/qt-5/qtoolbar.html#addAction-7.

jsulm

@JonB said in Debug output when calling QToolBar::addAction():

getting rid of all SIGNAL/SLOT()

this!

Perdrix

In the context of that code I tried:

t.addAction(dragRect, "", &editor, &DEditStars::dragButtonPressed());

and was awarded this nastygram:

1>C:\Users\amonra\Documents\source\repos\QImageView\QImageView\main.cpp(17,53): error C2352: 'DEditStars::dragButtonPressed': illegal call of non-static member function
1>C:\Users\amonra\Documents\source\repos\QImageView\QImageView\deditstars.h(61): message : see declaration of 'DEditStars::dragButtonPressed'

trying with:

t.addAction(dragRect, "", &editor, &editor.dragButtonPressed());

got me:

1>C:\Users\amonra\Documents\source\repos\QImageView\QImageView\main.cpp(17): error C2102: '&' requires l-value

This:

    t.addAction(dragRect, "", &editor, SLOT(dragButtonPressed()));

Does work, but it definitely is NOT clear that what you need to code from the docs. If you want me to use the other formats - how do they go?
So hows it supposed to go?

Bonnie

@Perdrix
Do you know how to call connect?
It is exactly the same...

Pl45m4

@Perdrix

&DEditStars::dragButtonPressed

New syntax without ( )

JonB

@Perdrix said in Debug output when calling QToolBar::addAction():
Just to be 100% clear, and get you on the right track of new syntax so you will like it(!), as @Pl45m4 has said the whole line needs to be:

t.addAction(dragRect, "", &editor, &DEditStars::dragButtonPressed);

Page https://wiki.qt.io/New_Signal_Slot_Syntax gives you comparative examples.