QVideoWidget not showing on QVBoxLayout with QScrollArea

Pedro Vicente

I have a scrollable widget that hosts many widgets on a vertical layout

Trying to add a QVideoWidget, it is not displayed .
This sample reproduces the issue
Thanks for any help

#include <QApplication>
#include <QMainWindow>
#include <QObject>
#include <QImage>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QTextEdit>
#include <QLabel>
#include <QMediaPlayer>
#include <QVideoWidget>
#include <QAudioOutput>
#include <QMediaMetaData>
#include <QVBoxLayout>
#include <QScrollArea>

int main(int argc, char** argv)
{
  QApplication app(argc, argv);

  QWidget* central = new QWidget;
  QScrollArea* scroll = new QScrollArea;
  QVBoxLayout* layout = new QVBoxLayout(central);
  scroll->setWidget(central);
  scroll->setWidgetResizable(true);

  int i = 0;
  while (i < 2)
  {
    QString str = "\U0001F600";
    QTextEdit* text = new QTextEdit();
    text->setReadOnly(true);
    text->setGeometry(0, 0, 100, 100);
    text->setText(str);
    text->show();
    layout->addWidget(text);
    i++;
  }

  
  QMediaPlayer* player = new QMediaPlayer;
  QAudioOutput* audio = new QAudioOutput;
  player->setAudioOutput(audio);
  QUrl url_media("http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4");
  player->setSource(url_media);
  QVideoWidget* video = new QVideoWidget();
  player->metaData().value(QMediaMetaData::Resolution).toSize();
  video->setGeometry(0, 0, 300, 200);
  player->setVideoOutput(video);
  video->show();
  audio->setVolume(50);
  player->play();

  layout->addWidget(video);

  QMainWindow* w = new QMainWindow;
  w->setGeometry(50, 50, 480, 320);
  w->setCentralWidget(scroll);
  w->show();

  return app.exec();
}

The video starts playing, just now showing in any window

SGaist

Hi,

Which version of Qt ?
On which OS ?
Does the video show properly if the QVideoWidget is shown standalone ?

Pedro Vicente

@SGaist said in QVideoWidget not showing on QVBoxLayout with QScrollArea:

Does the video show properly if the QVideoWidget is shown standalone ?

Yes

In this sample, without any layout and scroll code , it does show

I don't think it's platform or QT version dependent
Tried on Windows, Mac, with 6.70 and 6.6.3

I

It seems just a basic error in my code (I have been away from QT coding for a while, this is a recent comeback)

As always, thanks for the quick feedback !

mainwindow.cpp

MainWindow::MainWindow()
{
  QString str = "\U0001F600";
  QTextEdit* text = new QTextEdit(this);
  text->setReadOnly(true);
  text->setGeometry(0, 0, 100, 100);
  text->setText(str);
  text->show();

  network = new QNetworkAccessManager(this);
  connect(network, &QNetworkAccessManager::finished, this, &MainWindow::on_finished);
  QUrl url("http://100.36.4.152/image/image.jpg");
  QNetworkRequest request(url);
  network->get(request);
  label = new QLabel(this);

  QMediaPlayer* player = new QMediaPlayer;
  QAudioOutput* audio = new QAudioOutput;
  player->setAudioOutput(audio);
 QUrl url_media("http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4");
  player->setSource(url_media);
  QVideoWidget* video = new QVideoWidget(this);
  player->metaData().value(QMediaMetaData::Resolution).toSize();
  video->setGeometry(700, 0, 300, 200);
  player->setVideoOutput(video);
  video->show();
  audio->setVolume(50);
  player->play();

}

///////////////////////////////////////////////////////////////////////////////////////
//MainWindow::on_finished
///////////////////////////////////////////////////////////////////////////////////////

void MainWindow::on_finished(QNetworkReply* reply)
{
  QByteArray data = reply->readAll();
  image.loadFromData(data);
  label->setPixmap(QPixmap::fromImage(image));
  label->setGeometry(0, 100, image.width(), image.height());
  emit loaded();
}

header file


class MainWindow : public QMainWindow
{
  Q_OBJECT
public:
  MainWindow();

protected:
  QImage image;
  QNetworkAccessManager* network;
  QLabel* label;

signals:
  void loaded();

protected slots:
  void on_finished(QNetworkReply* reply);

};

Pedro Vicente

@Pedro-Vicente said in QVideoWidget not showing on QVBoxLayout with QScrollArea:

QVideoWidget* video = new QVideoWidget(this);

To note that in the no layout version, the widgets are added as children of the main window ( "this" as argument)

QVideoWidget* video = new QVideoWidget(this);

without it , the video displays as an additional new window (that cannot be resized or moved)

QVideoWidget* video = new QVideoWidget();

JoeCFD

@Pedro-Vicente
if you put widgets into a layout, you do not set position for all widgets in the layout;
video->setFixedSize( 300, 200 );

Pedro Vicente

@JoeCFD said in QVideoWidget not showing on QVBoxLayout with QScrollArea:

video->setFixedSize( 300, 200 );

yes, that was it!
thanks

 //video->setGeometry(0, 0, 300, 200);
 video->setFixedSize(300, 200);

Pedro Vicente

@JoeCFD said in QVideoWidget not showing on QVBoxLayout with QScrollArea:

@Pedro-Vicente
if you put widgets into a layout, you do not set position for all widgets in the layout;
video->setFixedSize( 300, 200 );

There is still one issue, the scroll does now show in this sample

MainWindow::MainWindow()
{
  QWidget* central = new QWidget;
  QScrollArea* scroll = new QScrollArea;
  QVBoxLayout* layout = new QVBoxLayout(scroll);
  scroll->setWidget(central);
  scroll->setWidgetResizable(true);

  QString str = "\U0001F600";
  QTextEdit* text = new QTextEdit();
  text->setReadOnly(true);
  text->setGeometry(0, 0, 100, 100);
  text->setText(str);
  text->show();

  network = new QNetworkAccessManager(this);
  connect(network, &QNetworkAccessManager::finished, this, &MainWindow::on_finished);
  QUrl url("http://100.36.4.152/image/image.jpg");
  QNetworkRequest request(url);
  network->get(request);
  label = new QLabel();

  QMediaPlayer* player = new QMediaPlayer;
  QAudioOutput* audio = new QAudioOutput;
  player->setAudioOutput(audio);
  QUrl url_media("http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4");
  player->setSource(url_media);
  QVideoWidget* video = new QVideoWidget();
  player->metaData().value(QMediaMetaData::Resolution).toSize();
  video->setFixedSize(300, 200);
  player->setVideoOutput(video);
  video->show();
  audio->setVolume(50);
  player->play();

  layout->addWidget(text);
  layout->addWidget(label);
  layout->addWidget(video);

  setCentralWidget(scroll);
}

JoeCFD

@Pedro-Vicente the same thing for all widgets and better to set parents to widgets as well. Otherwise, you may have memory leak.
setGeometry( x, y, width, height ) call is wrong because it sets position and size.

jsulm

@JoeCFD said in QVideoWidget not showing on QVBoxLayout with QScrollArea:

Otherwise, you may have memory leak.

No, if a widget is added to a layout the layout takes the ownership.

JoeCFD

@jsulm True. Thanks.