c++ - Qt SplashScreen w/ Fading Logo Not Running Animation -

i creating loading screen app , want implement 2 qlabels (background , overlay) in overlay glowing outline of background. want overlay fade in opacity (0.0 - 1.0) use qpropertyanimation windowopacity property label, nothing works this. here full source code.

main.cpp:

#include "mainwindow.h" #include "imagefade.h"  #include <qapplication> #include <qsplashscreen> #include <qtimer> #include <qhboxlayout> #include <qlabel>  int main(int argc, char *argv[]) {     qapplication a(argc, argv);      qsplashscreen *splashscreen = new qsplashscreen();     splashscreen->resize(500, 500);      qpixmap bkgdimage(":/files/images/launch/launch.png");     qpixmap ovlyimage(":/files/images/launch/launch-glow.png");      imagefade *imagelabel= new imagefade(splashscreen);     imagelabel->setbackgroundimage(bkgdimage);     imagelabel->setoverlayimage(ovlyimage);      imagelabel->startanimation(5000);     splashscreen->show();      mainwindow w;      qtimer::singleshot(2500, splashscreen, slot(close()));     qtimer::singleshot(2500, &w, slot(show()));      //w.show();      return a.exec(); } 

imagefade.cpp:

#include "imagefade.h" #include <qdebug>  imagefade::imagefade(qwidget *parent) : qwidget(parent) {     bkgdlabel = new qlabel();     ovlylabel = new qlabel();      bkgdlabel->setgeometry(qrect(qpoint(0, 0), qsize(parent->size())));     ovlylabel->setgeometry(qrect(qpoint(0, 0), qsize(parent->size())));      fadeanimation = new qpropertyanimation(ovlylabel, "windowopacity");     fadeanimation->setloopcount(5);     fadeanimation->setstartvalue(1.0);     fadeanimation->setendvalue(0.0);     fadeanimation->seteasingcurve(qeasingcurve::outquad);     connect(fadeanimation, signal(statechanged(qabstractanimation::state,qabstractanimation::state)), this, slot(statechanged(qabstractanimation::state,qabstractanimation::state))); }  imagefade::~imagefade() {     //fadeanimation->stop(); }  void imagefade::setbackgroundimage(qpixmap bkgdimg) {     this->bkgdimg = bkgdimg;     bkgdlabel->setpixmap(bkgdimg.scaled(size(), qt::keepaspectratio, qt::smoothtransformation)); }  void imagefade::setoverlayimage(qpixmap ovlyimg) {     this->ovlyimg = ovlyimg;     ovlylabel->setpixmap(ovlyimg.scaled(size(), qt::keepaspectratio, qt::smoothtransformation)); }  void imagefade::startanimation(int fadedelay) {     fadeanimation->setduration(fadedelay);      fadeanimation->start(qabstractanimation::deletewhenstopped); }  void imagefade::stop() {     fadeanimation->stop(); }  void imagefade::statechanged(qabstractanimation::state state1, qabstractanimation::state state2) {     qdebug() << state1 << state2; } 

imagefade.h:

#ifndef imagefade_h #define imagefade_h  #include <qwidget> #include <qlabel> #include <qlabel> #include <qpropertyanimation>  class imagefade : public qwidget {     q_object public:     explicit imagefade(qwidget *parent = nullptr);     ~imagefade();      void setbackgroundimage(qpixmap bkgdimg);     void setoverlayimage(qpixmap ovlyimg);      void startanimation(int fadedelay);     void stop();  signals:  public slots:     void statechanged(qabstractanimation::state state1, qabstractanimation::state state2);  private:     qlabel *bkgdlabel;     qlabel *ovlylabel;      qpixmap bkgdimg;     qpixmap ovlyimg;      qpropertyanimation *fadeanimation; };  #endif // imagefade_h 

i had same problem few days ago. can share code how hide/show label using animation.

    qgraphicsopacityeffect *opacity;      opacity = new qgraphicsopacityeffect("label_name");     ui->"label_name"->setgraphicseffect(opacity);     qpropertyanimation *anim = new qpropertyanimation(opacity, "opacity");     anim->seteasingcurve(qeasingcurve::linear);     anim->setstartvalue(1.0);     anim->setendvalue(0.01);     anim->setduration(1000);     anim->start(qabstractanimation::deletewhenstopped); 

this small example how hide qlabel using qpropertyanimation. can vise versa (show label) if set start value 0.01 , end value 1.0