Question

How would one extend the standard icons provided by the QStyle class with support for Windows and Linux in mind?

namespace Ui {
  class TVLoader;
}

class TVLoader : public QMainWindow
{
  Q_OBJECT

public:
  explicit TVLoader(QWidget *parent = 0) :
  QMainWindow(parent),
  ui(new Ui::TVLoader)
{
  ui->setupUi(this);
  ui->actionAdd_TV_Show->setIcon(style()->standardIcon(?)); // this is where I would need some kind of "Add" icon which unfortunately doesn't exist
}

Answer 1

You man want to subclass QStyle if you want to provide your own icons, reimplement the standardIconImplementation() slot in your subclass and return a new icon from there. Below is an example:

class MyProxyStyle : public QProxyStyle
{
    Q_OBJECT

public:
    MyProxyStyle(QStyle *style = 0) : QProxyStyle(style) { }

public slots:
    QIcon standardIconImplementation(StandardPixmap standardIcon,
                                     const QStyleOption *option = 0,
                                     const QWidget *widget = 0) const
    {
        // check the standardIcon parameter for the icon type 
        if (standardIcon==QStyle::SP_DesktopIcon)
        {
            // return your new icon here
            standardIcon = QStyle::SP_DirIcon;
        }
        return QProxyStyle::standardIconImplementation(standardIcon, option, widget);
    }
};

here’s how can you use it:

// set new style for your widget
setStyle(new MyProxyStyle(style()));
// return different icon for QStyle::SP_DesktopIcon
action0->setIcon(style()->standardIcon(QStyle::SP_DesktopIcon));

hope this helps, regards