Program crash when it loads videos from multiple directories continuously

[Kinesis]

I have code that loads videos from directories which are chosen by user.There will be many subdirs in listwidget , and the user can choose continuously.But when the user change the subdirectories quickly, the program crashed . Video player include play/pause button and postion slider(can skip,change position according to video playing time) . Here is the code .

connect (button , &QAbstractButton::clicked,[label,listWidget_main,listWidget_dirList,this]{

        QDir directory = QFileDialog::getExistingDirectory(this, tr("Open Directory"),"/home",

                                                           QFileDialog::ShowDirsOnly| QFileDialog::DontResolveSymlinks);

        label->setText(directory.absolutePath());
        QStringList dirs = directory.entryList(QDir::Dirs|QDir::NoDotAndDotDot);
        listWidget_dirList->addItems(dirs);

        connect(listWidget_dirList, & QListWidget::currentRowChanged,[listWidget_dirList,directory,listWidget_main,this](int currentRow)

        {
            //listWidget_dirList->setEnabled(false);
            listWidget_main->show();
            listWidget_main->clear();

            QListWidgetItem *item = listWidget_dirList->item(currentRow);
            QDir dir = directory.absolutePath() + '/'+item->text()  ;
            dir.setNameFilters({"*.mp4" , "*.avi" , "*.flv" , "*.mwv"});

            for(const QFileInfo & finfo: dir.entryInfoList()){
                QMediaPlayer *mediaPlayer = new QMediaPlayer();
                mediaPlayer->setMedia(QUrl::fromLocalFile(finfo.absoluteFilePath()));
                videoItem = new QGraphicsVideoItem;
                videoItem->setSize(QSize(320,240));
                QGraphicsScene *scene = new QGraphicsScene(this);
                QGraphicsView *graphicsView = new QGraphicsView(scene);
                mediaPlayer->setVideoOutput(videoItem);

                QPushButton *m_playButton = new QPushButton();
                m_playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

                connect(m_playButton, &QAbstractButton::clicked, [mediaPlayer]() {
                    switch (mediaPlayer->state()) {
                    case QMediaPlayer::PlayingState:
                        mediaPlayer->pause();
                        break;
                    default:
                        mediaPlayer->play();
                        break;
                    }
                });


                connect(mediaPlayer, &QMediaPlayer::stateChanged, [m_playButton, this](QMediaPlayer::State state) {
                    switch(state) {
                    case QMediaPlayer::PlayingState:
                        m_playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
                        break;
                    default:
                        m_playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
                        break;
                    }
                });



                QSlider *m_positionSlider = new QSlider(Qt::Horizontal,this);
                m_positionSlider->setRange(0,mediaPlayer->duration() / 1000);


                connect(mediaPlayer, &QMediaPlayer::positionChanged ,[m_positionSlider, this](qint64 position){

                    m_positionSlider->setValue(position);
                });

                connect(mediaPlayer, &QMediaPlayer::durationChanged ,[m_positionSlider, this](qint64 duration){

                    m_positionSlider->setRange(0,duration);
                });


                connect(m_positionSlider ,&QAbstractSlider::sliderMoved, [mediaPlayer ,this] (int position){

                    mediaPlayer->setPosition(position);
                });




                auto    item = new QListWidgetItem("", listWidget_main);
                auto    widget = new QWidget;
                auto    label = new QLabel(finfo.fileName());
                auto    vb = new QVBoxLayout;

                QBoxLayout *controlLayout = new QHBoxLayout;
                controlLayout->setMargin(0);
                controlLayout->addWidget(m_playButton);
                controlLayout->addWidget(m_positionSlider);

                vb->addWidget(label);
                vb->addWidget(graphicsView);
                vb->addLayout(controlLayout);
                widget->setLayout(vb);
                widget->setMinimumSize(340, 340);
                listWidget_main->setItemWidget(item,widget);
                player.append(mediaPlayer);
                scene->addItem(videoItem);



            }
});
    });

The debugger shows that this part is where it stopped.

connect(mediaPlayer, &QMediaPlayer::positionChanged ,[m_positionSlider, this](qint64 position){

                    m_positionSlider->setValue(position);
                });

                connect(mediaPlayer, &QMediaPlayer::durationChanged ,[m_positionSlider, this](qint64 duration){

                   m_positionSlider->setRange(0,duration);
                });

So I disabled position slider and it works completely fine . But I need to use position slider . I don't know how can I fix it.

[jsulm]

@Kinesis said in Program crash when it loads videos from multiple directories continuously:

connect(listWidget_dirList, & QListWidget::currentRowChanged,

Are you aware that you do this connect everytime your "button" is clicked?

I guess your "m_positionSlider" was deleted and new one created in the meantime? Where do you actually delete them? I only see where you create new m_positionSlider. Where do you delete "mediaPlayer"? The code you posted looks like you have many memory leaks.

[Kinesis]

@jsulm
Yes I am aware that I do this connect everytime the "button" is clicked.

"I guess your "m_positionSlider" was deleted and new one created in the meantime? Where do you actually delete them?"
Ans:: This is all the code that I am doing now. I think I haven't delected mediaPlayer.
I also think that my code has memory leak . That's why I am stuck here.

[SGaist]

Hi,

You are continuously creating new objects (QMediaPlayer, QGraphicsView, etc.) without ever deleting them or re-using them. Start by fixing that and your leaks should stop.

[Kinesis]

@jsulm
As @SGaist said I am continuously creating new objects (QMediaPlayer, QGraphicsView, etc.) without ever deleting them or re-using them .
OK, how can I delect or reuse them . Ref please

[jsulm]

@Kinesis said in Program crash when it loads videos from multiple directories continuously:

OK, how can I delect or reuse them

Like any other object in C++

delete object;

You need to keep the pointers somewhere to be able to do so.

[Kinesis]

@jsulm
Ok , in my case where should I delete or reuse?

[jsulm]

@Kinesis You should delete them when they are not needed anymore