Load new view (.ui) from the previous view

[d_stranz]

I think in lines 6 and 7 you want "windowOpacity", not "windowOpacity()". And it probably should be:

QString( "windowOpacity" ).toLatin1();
// or
QString( "windowOpacity" ).toUtf8();

QString( "windowOpacity" ).toLatin1();
// or
QString( "windowOpacity" ).toUtf8();

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since the property name is a QByteArray type. I don't know which version is appropriate; you'll have to check.

Each time you create the new "second" window, that's a memory leak. "second" should be a member variable of MainWindow, and you should create it once in the MainWindow constructor. You haven't given it a size. You should also set its opacity to 0 so that when it is first shown, it is invisible because it is totally transparent. You do not want to hide "parent" in line 15, because that makes it disappear immediately instead of fading out.

As I said in my original post, connect parent's hide() slot to the "animation" finished() signal. This will cause it to actually be hidden when its opacity animation ends (at which point it is totally transparent).

You will find the 5 seconds is much too long for this. 2 - 3 seconds will probably look better and lead to less impatience.

You might also want to disable both widget when you start the dissolve so the user can't click on anything inside them. In the slot connected to the "animation2" finished() signal, you should enable "second".

[d_stranz]

I am sure you understand that .ui files are compiled into your program and are not used at runtime, right?

I was a bit wrong with this statement. See QUiLoader.

[anda_skoa]

I was a bit wrong with this statement. See QUiLoader.

Sure, but you were still quite right as that is almost never used.
Basically only if the application supports some form of user scripting and needs a way for scripts to load UI.

Cheers,
_

[d_stranz]

Agreed. I think it is a quite dangerous thing to put in the hands of a user who could make changes that destroy an app's GUI.

[das.joyita]

Hi, Thanks for the replies both of you. Sorry, but I am still confused. Not sure how to use QAbstractAnimation:: finished () linking to the hiding of parent view.

QPropertyAnimation *animation = new QPropertyAnimation(parent, QString("windowOpacity").toLatin1());//windowOpacity");
    QPropertyAnimation *animation2 = new QPropertyAnimation(second, QString("windowOpacity").toLatin1());//"windowOpacity");
    animation->setDuration(3000);
    animation2->setDuration(3000);
    animation2->setStartValue(0.0);
    ui->centralWidget->setEnabled(true);
    second->show();
    animation->setStartValue(1.0);
 
    animation->setEndValue(0.0);
    animation2->setEndValue(1.0);

QPropertyAnimation *animation = new QPropertyAnimation(parent, QString("windowOpacity").toLatin1());//windowOpacity");
    QPropertyAnimation *animation2 = new QPropertyAnimation(second, QString("windowOpacity").toLatin1());//"windowOpacity");
    animation->setDuration(3000);
    animation2->setDuration(3000);
    animation2->setStartValue(0.0);
    ui->centralWidget->setEnabled(true);
    second->show();
    animation->setStartValue(1.0);

    animation->setEndValue(0.0);
    animation2->setEndValue(1.0);

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I am doing the above code, but now things are running very quickly and I cant see any animation, only the second view. The first parent view is visible but behind the second view.

[d_stranz]

void MainWindow::dissolve( QWidget * pFadeOut, QWidget * pFadeIn )
{
	QByteArray	opacityProp( QString( "windowOpacity" ).toLatin1() );
	QPropertyAnimation *  pFadeOutAnimation = new QPropertyAnimation( pFadeOut, opacityProp );
	QPropertyAnimation *  pFadeInAnimation  = new QPropertyAnimation( pFadeIn,  opacityProp );
 
	int duration = 3000;
	pFadeOutAnimation->setDuration( duration );
	pDafeOutAnimation->setStartValue( 1.0 );
	pFadeOutAnimation->setEndValue( 0.0 );
 
        // Hide the fade out widget when the animation has stopped
	connect( pFadeOutAnimation, &QPropertyAnimation::finished, pFadeOut, &QWidget::hide );
 
        pFadeInAnimation->setDuration( duration );
	pFadeInAnimation->setStartValue( 0.0 );
	pFadeInAnimation->setEndValue( 1.0 );
 
        // Ensure the fade in widget is showing, but make it invisible by setting opacity to 0
	if ( !pFadeIn->isVisible() )
	{
		pFadeIn->setWindowOpacity( 0.0 );
		pFadeIn->show();
	}
 
	pFadeOutAnimation->start( QAbstractAnimation::DeleteWhenStopped );
	pFadeInAnimation->start( QAbstractAnimation::DeleteWhenStopped );
}

void MainWindow::dissolve( QWidget * pFadeOut, QWidget * pFadeIn )
{
	QByteArray	opacityProp( QString( "windowOpacity" ).toLatin1() );
	QPropertyAnimation *  pFadeOutAnimation = new QPropertyAnimation( pFadeOut, opacityProp );
	QPropertyAnimation *  pFadeInAnimation  = new QPropertyAnimation( pFadeIn,  opacityProp );
	
	int duration = 3000;
	pFadeOutAnimation->setDuration( duration );
	pDafeOutAnimation->setStartValue( 1.0 );
	pFadeOutAnimation->setEndValue( 0.0 );

        // Hide the fade out widget when the animation has stopped
	connect( pFadeOutAnimation, &QPropertyAnimation::finished, pFadeOut, &QWidget::hide );
	
        pFadeInAnimation->setDuration( duration );
	pFadeInAnimation->setStartValue( 0.0 );
	pFadeInAnimation->setEndValue( 1.0 );
	
        // Ensure the fade in widget is showing, but make it invisible by setting opacity to 0
	if ( !pFadeIn->isVisible() )
	{
		pFadeIn->setWindowOpacity( 0.0 );
		pFadeIn->show();
	}
	
	pFadeOutAnimation->start( QAbstractAnimation::DeleteWhenStopped );
	pFadeInAnimation->start( QAbstractAnimation::DeleteWhenStopped );
}

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Not tested, so may require some edits.

[das.joyita]

Thanks so much. Its works beautifully. You are a savior