Qt5: could not connect signal to slot

Question

I'm trying to upgrade my old Application.. (add it one more function). So, I added one more item in 'File' menu.

<addaction name="actionDownload_Firmware_Image"/>

<action name="actionDownload_Firmware_Image">


<property name="text">
    <string>&amp;Download Firmware Image</string>
   </property>
   <property name="menuRole">
    <enum>QAction::ApplicationSpecificRole</enum>
   </property>
  </action>

Defined my Slot here:

void MainWindow::on_actionDownload_Firmware_Image_triggered()

MainWindow.h>

private slots:
    void on_actionDownload_Firmware_Image_triggered();

So, I clean my project, run qmake, build project... Play it, and I get exactly the same GUI as before, no new Menu item.

When App is run, I get the following message>

QMetaObject::connectSlotsByName: No matching signal for on_actionDownload_Firmware_Image_triggered()

I noticed on other questions on stackoverflow that connectSlotsByName is not recommended for use, but all of my functions and slots are called exactly the same, so it should work like this.

I'm not sure why this is happening, any help is welcome.

Thanks!

Did you add your action by using the designer or did you just edit the .ui file with a text editor? — thuga
Now I tried just changing the text of About item in one of the menus and that didn't change after build. — Rorschach
It is a typical error. Try to add Q_OBJECT macro in your MainWindow declaration. And next time provide an SSCCE with your problem (not only several lines from class defination). — Dmitry Sazonov
I already have 'class MainWindow : public QMainWindow' '{' 'Q_OBJECT' Also, what could be SSCCE in this case, I can't post a few thousand lines of code, and this is the way to post the important ones. — Rorschach

Rorschach Rorschach · Accepted Answer · 2015-04-02T12:58:15

The problem is solved!

No coding was needed...

While compiling, Qt puts the ui_mainwindow.h in its newly created build folder, and not in the project folder.. So the app doesn't see the updated .h

After copying new .h to the project folder, doing qmake and building again, everything looks ok.

Qt5: could not connect signal to slot

2 Answers