dialog.cpp

#include "dialog.h"
#include "ui_dialog.h"
#include <QKeyEvent>
#include <QSignalMapper>
#include <QInputMethod>

Dialog::Dialog(QWidget *parent, Qt::WindowFlags flags) :
    QDialog(parent,flags),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
    signalMapper = new QSignalMapper(this);
    digitButtons = this->findChildren<QPushButton *>();
    for (int i=0;i<digitButtons.count();i++)
    {
    connect(digitButtons.at(i), SIGNAL(clicked()), signalMapper, SLOT(map()));
    signalMapper->setMapping(digitButtons.at(i), i);
    }
    connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(btn_clicked(int)));
    QLineEdit::setFocusPolicy(Qt::ClickFocus);
}

void Dialog::btn_clicked(int btn)
{
QKeyEvent keyEvent(QEvent::KeyPress, 0, Qt::NoModifier, digitButtons.at(btn)->text(), false, 0);
QApplication::sendEvent(this->focusWidget(), &keyEvent);
}

Dialog::~Dialog()
{
    delete ui;
}