How to check pushButtons with draging the mouse QT ? MouseMoveEvent

I have 5 pushButtons ( pushButton_i ) i = 1, 2, 3, 4, 5. What I want to do is to drag the mouse ( button pressed ) and then setText of checked buttons on "Yes", otherwise on "NO". I tried the following code but the result is : When I press the mouse Button and then move it a little bit, all buttons' texts are set on "NO". This is my code :

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QString>
#include<QEvent>
#include <QMouseEvent>
#include <QDebug>
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

}

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

void MainWindow::mouseMoveEvent(QMouseEvent *event)
{
    QString key;
    for (int i=1;i<=5;i++){
        key = QString("pushButton_%1").arg(i);
        QPushButton *button = ui->centralwidget->findChild<QPushButton*>(key);
        QRect widgetRect = button->geometry();
        widgetRect.moveTopLeft(button->parentWidget()->mapToGlobal(widgetRect.topLeft()));
        if (button->rect().contains(event->pos())) button->setText("Yes");
        else button->setText("No");
}

}

Can someone please explain to me what is going on ?