a.installEventFilter(&a);

setFocusPolicy(Qt::StrongFocus);

#ifndef MAIN_H_05555
#define MAIN_H_05555

/// Класс переопределения фильтра событий
class Application: public QApplication
{
    Q_OBJECT

protected:
    bool eventFilter(QObject* object, QEvent* events);

public:
    Application(int& argc, char** argv): QApplication(argc, argv) {}
    ~Application() {}
};

#endif //MAIN_H_05555

#include <QtGui/QApplication>
#include <QtGui>

#include "LibraryBuilder.h"
#include "main.h"

/// Фильтрация событий
bool Application::eventFilter(QObject* object, QEvent* events)
{
    bool p1 = true;
    if(events -> type() == QEvent::KeyPress)
    {
        QKeyEvent* key_events(static_cast<QKeyEvent*> (events));
        switch(key_events -> key())
        {
        case Qt::Key_Plus:
            p1 = false;
        break;
        case Qt::Key_Minus:
        break;
        }
        return QApplication::eventFilter(object, events);
    }

    return QApplication::eventFilter(object, events);
}

/// Главная функция запуска приложения
int main(int argc, char *argv[])
{
    Application a(argc, argv);
    LibraryBuilder w;
    w.show();
    a.connect(&a, SIGNAL(lastWindowClosed()), &a, SLOT(quit()));
    return a.exec();
}