Qt 5.7 | Qt Multimedia | Video Widget Example | videoplayer.cpp Example File

Qt 5.7.1 Reference Documentation

# videoplayer.cpp Example File

multimediawidgets/videowidget/videoplayer.cpp

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      ** This file is part of the examples of the Qt Toolkit.
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      #include "videoplayer.h"

      #include <QtWidgets>
      #include <qvideowidget.h>
      #include <qvideosurfaceformat.h>

      VideoPlayer::VideoPlayer(QWidget *parent)
          : QWidget(parent)
          , mediaPlayer(0, QMediaPlayer::VideoSurface)
          , playButton(0)
          , positionSlider(0)
          , errorLabel(0)
      {
          QVideoWidget *videoWidget = new QVideoWidget;

          QAbstractButton *openButton = new QPushButton(tr("Open..."));
          connect(openButton, &QAbstractButton::clicked, this, &VideoPlayer::openFile);

          playButton = new QPushButton;
          playButton->setEnabled(false);
          playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

          connect(playButton, &QAbstractButton::clicked,
                  this, &VideoPlayer::play);

          positionSlider = new QSlider(Qt::Horizontal);
          positionSlider->setRange(0, 0);

          connect(positionSlider, &QAbstractSlider::sliderMoved,
                  this, &VideoPlayer::setPosition);

          errorLabel = new QLabel;
          errorLabel->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Maximum);

          QBoxLayout *controlLayout = new QHBoxLayout;
          controlLayout->setMargin(0);
          controlLayout->addWidget(openButton);
          controlLayout->addWidget(playButton);
          controlLayout->addWidget(positionSlider);

          QBoxLayout *layout = new QVBoxLayout;
          layout->addWidget(videoWidget);
          layout->addLayout(controlLayout);
          layout->addWidget(errorLabel);

          setLayout(layout);

          mediaPlayer.setVideoOutput(videoWidget);
          connect(&mediaPlayer, &QMediaPlayer::stateChanged,
                  this, &VideoPlayer::mediaStateChanged);
          connect(&mediaPlayer, &QMediaPlayer::positionChanged, this, &VideoPlayer::positionChanged);
          connect(&mediaPlayer, &QMediaPlayer::durationChanged, this, &VideoPlayer::durationChanged);
          typedef void (QMediaPlayer::*ErrorSignal)(QMediaPlayer::Error);
          connect(&mediaPlayer, static_cast<ErrorSignal>(&QMediaPlayer::error),
                  this, &VideoPlayer::handleError);
      }

      VideoPlayer::~VideoPlayer()
      {
      }

      void VideoPlayer::openFile()
      {
          QFileDialog fileDialog(this);
          fileDialog.setAcceptMode(QFileDialog::AcceptOpen);
          fileDialog.setWindowTitle(tr("Open Movie"));
          QStringList supportedMimeTypes = mediaPlayer.supportedMimeTypes();
          if (!supportedMimeTypes.isEmpty())
              fileDialog.setMimeTypeFilters(supportedMimeTypes);
          fileDialog.setDirectory(QStandardPaths::standardLocations(QStandardPaths::MoviesLocation).value(0, QDir::homePath()));
          if (fileDialog.exec() == QDialog::Accepted)
              setUrl(fileDialog.selectedUrls().constFirst());
      }

      void VideoPlayer::setUrl(const QUrl &url)
      {
          errorLabel->setText(QString());
          setWindowFilePath(url.isLocalFile() ? url.toLocalFile() : QString());
          mediaPlayer.setMedia(url);
          playButton->setEnabled(true);
      }

      void VideoPlayer::play()
      {
          switch(mediaPlayer.state()) {
          case QMediaPlayer::PlayingState:
              mediaPlayer.pause();
              break;
          default:
              mediaPlayer.play();
              break;
          }
      }

      void VideoPlayer::mediaStateChanged(QMediaPlayer::State state)
      {
          switch(state) {
          case QMediaPlayer::PlayingState:
              playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
              break;
          default:
              playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
              break;
          }
      }

      void VideoPlayer::positionChanged(qint64 position)
      {
          positionSlider->setValue(position);
      }

      void VideoPlayer::durationChanged(qint64 duration)
      {
          positionSlider->setRange(0, duration);
      }

      void VideoPlayer::setPosition(int position)
      {
          mediaPlayer.setPosition(position);
      }

      void VideoPlayer::handleError()
      {
          playButton->setEnabled(false);
          const QString errorString = mediaPlayer.errorString();
          QString message = "Error: ";
          if (errorString.isEmpty())
              message += " #" + QString::number(int(mediaPlayer.error()));
          else
              message += errorString;
          errorLabel->setText(message);
      }