How to launch the QMainWindow with a fade in animation?

[Roberrt]

I tried launching my window this way:

#include "stdafx.h"
#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    setWindowOpacity(0);

    QGraphicsOpacityEffect* eff = new QGraphicsOpacityEffect(this);

    QPropertyAnimation* ani = new QPropertyAnimation(eff, "windowOpacity");
    ani->setDuration(3000);
    ani->setStartValue(0);
    ani->setEndValue(1);
    ani->setEasingCurve(QEasingCurve::OutBack);
    ani->start(QPropertyAnimation::DeleteWhenStopped);
}

---

#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    MainWindow w;
    w.show();
    return a.exec();
}

But the window never became visible, I would like to it be initialized with a fade in effect.

What's the proper way to achieve it?

[JoeCFD]

@Roberrt said in How to launch the QMainWindow with a fade in animation?:

QPropertyAnimation

Can you try?
ani->setTargetObject( this );
before start call.