Qt Labs Forum » General discussions

1. 
   mbejerano
   Member

   Is there a way to differentiate between which QAction's triggered() signal called a given slot? I have an application that creates its menus dynamically and I don't know at compile time how many there are going to be (hence the dynamic nature of the problem). I know that in Java I can determine the actionCommand or menu item identifier that called a given handler. Is there a mechanism in place to do this in Qt? ... and if so, where in the online help will it tell me?

   Posted: 1 month #

2. 
   mbejerano
   Member

   Figured it out. Turned out to be much simpler than I expected. You simply need to subclass QAction and provide a more detailed signal/slot message than you would normally have (with connecting to triggered() in QAction):

   class QA2 : public QAction {
    Q_OBJECT
   
   private:
    QString command;
   
   public:
    // implement all of QAction's ctors...
    QA2(QObject* parent) : QAction() { connectMe(); }
    .
    .
    .
    void connectMe() { connect(this, SIGNAL(triggered()), this, SLOT(triggered())); }
    QString getCommand() { return this->command; }
   
   signals:
    void triggered(QA2* qa2);
   
   private slots:
    void triggered() { emit(triggered(this)); }
   };
   

   You then can connect the menu action to whatever signal/slot you like:

   
   QMenu* menu = new QMenu("&Menu");
   QA2* barfu = new QA2(tr("&Barfu"), menu);
   barfu->setCommand(tr("print 'goodbye'"));
   barfu->setShortcut(tr("Ctrl+B"));
   connect(barfu, SIGNAL(triggered(QA2*)), this, SLOT(handleMenuAction(QA2*)));
   menu->addAction(edit_Barfu);
   

   Your class simply implements some form of handleMenuAction(QA2*) that then can have more information about which menu item was called.

   Simple!

   P.S. This forum SERIOUSLY needs a "Preview before post" button

   Posted: 1 month #

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