I want to animate error messages inside the status bar of my application.
I use a QLabel for the statusbar.

On status bar change i do the following:

Qt Code: 
  1. void sectiona::statusBarChanged(const QString& text, bool message)
  2. {
  3.   QLabel* b=m_gui->m_textOut;
  4.   QString newtext;
  5.   oldStatusBarText=b->text();
  6.   if(message==false)
  7.   {
  8.     b->setText(text);
  9.     return;
  10.   }else //animated message
  11.   {
  12.     newtext=text;
  13.     newtext=newtext.prepend("<font color=\"red\"><b>").append("</b></font>");
  14.     b->setText(newtext);
  15.     QGraphicsOpacityEffect* effect=new QGraphicsOpacityEffect(b);
  16.     b->setGraphicsEffect(effect);
  17.     QPropertyAnimation* animation=new QPropertyAnimation(effect,"opacity");
  18.     effect->setOpacity(0.0);
  19.     animation->setDuration(3000);
  20.     animation->setKeyValueAt(0.0,1.0);
  21.     animation->setKeyValueAt(0.9,1.0);
  22.     animation->setKeyValueAt(1.0,0.0);
  23.     animation->setEasingCurve(QEasingCurve::InOutCubic);
  24.     connect(animation,SIGNAL(finished()),this,SLOT(statusBarAnimationFinished()));
  25.     animation->start(QAbstractAnimation::DeleteWhenStopped);  
  26.   };
  27. }
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if the new status bar is a temporary message I animate the fadeout for 3seconds and then on the finish of the animation I restore the permanent status bar text:

Qt Code: 
  1. void sectiona::statusBarAnimationFinished()
  2. {
  3.   QLabel* b=m_gui->m_textOut;
  4.   QGraphicsOpacityEffect* effect=new QGraphicsOpacityEffect(b);
  5.   effect->setOpacity(0.0);
  6.   qDebug()<<effect->opacity();
  7.   b->setText(oldStatusBarText);
  8.   qDebug()<<effect->opacity();
  9.   b->setGraphicsEffect(effect);
  10.   qDebug()<<effect->opacity();
  11.   b->setText(oldStatusBarText);
  12.   qDebug()<<effect->opacity();
  13.   effect->setOpacity(1.0);
  14.  qDebug()<<effect->opacity();
  15. }
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It works fine except a minor detail. The qDebug statements return:
Qt Code: 
  1. 0
  2. 0
  3. 0
  4. 0
  5. 1
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, so the opacity changes only on the final statement, <b>BUT</b> the previous text blinks for a frame before setting the oldStatusBarText
I want to smoothly disappear the message, and the just update the QLabel with the previous text.
Any ideas?