How to do auto show/hide a widget in Qt

[rawfool]

I tried QGraphicsView & QGraphicsSCene, but I not working as I expected. I'm calling the widget to show after 3 seconds using a singleshot timer. But I see the widget is flashing and disappearing.
Below is the way how I implemented see how it comes out.

#include "ccentralwidget.h"
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QTimer>
 
CMainWidget::CMainWidget(QWidget *parent) :
    QWidget(parent)
{
    this->setStyleSheet("background-color: lightGray;");
    this->setFixedSize(650, 450);
    m_widget = new CMenuWidget();
 
    QTimer::singleShot(3000, this, SLOT(showMenuWidget()));
}
 
CMainWidget::~CMainWidget()
{
    delete m_widget;
}
 
void CMainWidget::showMenuWidget()
{
    QGraphicsScene scene;
    scene.addWidget(m_widget);
    scene.setSceneRect(0, 30, 60, 250);
 
    QGraphicsView view(&scene);
    view.show();
 
}

#include "ccentralwidget.h"
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QTimer>

CMainWidget::CMainWidget(QWidget *parent) :
    QWidget(parent)
{
    this->setStyleSheet("background-color: lightGray;");
    this->setFixedSize(650, 450);
    m_widget = new CMenuWidget();

    QTimer::singleShot(3000, this, SLOT(showMenuWidget()));
}

CMainWidget::~CMainWidget()
{
    delete m_widget;
}

void CMainWidget::showMenuWidget()
{
    QGraphicsScene scene;
    scene.addWidget(m_widget);
    scene.setSceneRect(0, 30, 60, 250);

    QGraphicsView view(&scene);
    view.show();

}

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And I tried it using QPropertyAnimation also, but it's giving some error/warning messages output.
I'm calling the below slot in singleshot timer the same way as shown in the above code.

void CCentralWidget::showMenuWidget()
{
    QPropertyAnimation *animation = new QPropertyAnimation(m_widget, "MyMenu");
    animation->setDuration(2000);
    animation->setStartValue(QRect(0, 0, 100, 30));
    animation->setEndValue(QRect(250, 250, 100, 30));
 
    animation->start();
}

void CCentralWidget::showMenuWidget()
{
    QPropertyAnimation *animation = new QPropertyAnimation(m_widget, "MyMenu");
    animation->setDuration(2000);
    animation->setStartValue(QRect(0, 0, 100, 30));
    animation->setEndValue(QRect(250, 250, 100, 30));

    animation->start();
}

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//Output Message:
QPropertyAnimation: you're trying to animate a non-existing property MyMenu of your QObject

//Output Message:
QPropertyAnimation: you're trying to animate a non-existing property MyMenu of your QObject

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I need to show/hide the widget the same way how the left app menu widget is shown/hidden on mouse move to the left area in Ubuntu unity and this kind of graphics can be seen a text editor called Scribes.
So for now I'm trying to achieve the same transition on singleshot timer, later I call it in movemove event.
Kindly help me. Thank you.