title: Qt: No defined slots show up in Signal & Slot Editing
body: <p>I have declared three slots in my <code>mainwindow.h</code> and given their definitions in the implementation file. Here is the MainWindow class:</p>
  
  <pre><code>class MainWindow : public QMainWindow
  {
      Q_OBJECT
  
  public:
      explicit MainWindow(QWidget *parent = 0);
      ~MainWindow();
  
  signals:
      void nextImage(int direction);
  
  private slots:
      void updateImage(void);
      void cameraControl(void);
      void cameraStart(void);
  
  private:
      Ui::MainWindow *ui;
      CMUCamera *camera;
      ImageProcessing *process;
      RenderImage *renderImage;
      bool saveImgFlg;
      QString path;
  };
  </code></pre>
  
  <p>Going to mainwindow.ui, I have designed a menu bar for the user interface. There are three QActions, as shown in the figure below: 
  <a href="https://i.stack.imgur.com/NR0DG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NR0DG.png" alt="enter image description here"></a></p>
  
  <p>Then, I do the signal and slot editing. But the defined slots (<code>udpateImage</code>, <code>cameraStart</code> and <code>cameraControl</code>) in the header file do not appear in the slot list, as shown in the figure below:</p>
  
  <p><a href="https://i.stack.imgur.com/ZasAW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZasAW.png" alt="enter image description here"></a></p>
  
  <p>Are there any other steps I missed here or is there something I did wrong? It is also noted <code>QMainWindow</code>, in the framework of which these slots should show up, I guess, is also not displayed in the list.</p>