I would subclass QAction and add some logic for the states in which it can be. It is never a good idea to hardcode the color of something into the name of a method. By subclassing QAction, the look and feel of it is encapsulated.
This could be something like this:
Header file:
class StateAction : public QAction
{
Q_OBJECT
public:
explicit StateAction(QObject *parent = 0);
public slots:
void start();
void stop();
void pause();
};
Implementation file:
StateAction::StateAction(QObject *parent) :
QAction(parent)
{
this->stop();
}
void StateAction::start()
{
this->setIcon(QIcon(":/states/start.png"));
}
void StateAction::stop()
{
this->setIcon(QIcon(":/states/stop.png"));
}
void StateAction::pause()
{
this->setIcon(QIcon(":/states/pause.png"));
}
Now, in your MainWindow you can use that custom QAction simply by connecting its slots to the right signals:
Header file:
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
signals:
void startedComputing();
void finishedComputing();
void pausedComputing();
private:
void createActions();
void createToolbars();
void createConnections();
StateAction *m_stateAction;
};
Implementation file:
...
void MainWindow::createConnections()
{
connect(this, SIGNAL(startedComputing()), m_stateAction, SLOT(start()));
connect(this, SIGNAL(finishedComputing()), m_stateAction, SLOT(stop()));
connect(this, SIGNAL(pausedComputing()), m_stateAction, SLOT(pause()));
}