Qt 5.9 | Qt Multimedia | Media Player Example | playercontrols.cpp Example File

Qt 5.9.4 Reference Documentation

# playercontrols.cpp Example File

multimediawidgets/player/playercontrols.cpp

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      #include "playercontrols.h"

      #include <QBoxLayout>
      #include <QSlider>
      #include <QStyle>
      #include <QToolButton>
      #include <QComboBox>
      #include <QAudio>

      PlayerControls::PlayerControls(QWidget *parent)
          : QWidget(parent)
          , playerState(QMediaPlayer::StoppedState)
          , playerMuted(false)
          , playButton(0)
          , stopButton(0)
          , nextButton(0)
          , previousButton(0)
          , muteButton(0)
          , volumeSlider(0)
          , rateBox(0)
      {
          playButton = new QToolButton(this);
          playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

          connect(playButton, SIGNAL(clicked()), this, SLOT(playClicked()));

          stopButton = new QToolButton(this);
          stopButton->setIcon(style()->standardIcon(QStyle::SP_MediaStop));
          stopButton->setEnabled(false);

          connect(stopButton, SIGNAL(clicked()), this, SIGNAL(stop()));

          nextButton = new QToolButton(this);
          nextButton->setIcon(style()->standardIcon(QStyle::SP_MediaSkipForward));

          connect(nextButton, SIGNAL(clicked()), this, SIGNAL(next()));

          previousButton = new QToolButton(this);
          previousButton->setIcon(style()->standardIcon(QStyle::SP_MediaSkipBackward));

          connect(previousButton, SIGNAL(clicked()), this, SIGNAL(previous()));

          muteButton = new QToolButton(this);
          muteButton->setIcon(style()->standardIcon(QStyle::SP_MediaVolume));

          connect(muteButton, SIGNAL(clicked()), this, SLOT(muteClicked()));

          volumeSlider = new QSlider(Qt::Horizontal, this);
          volumeSlider->setRange(0, 100);

          connect(volumeSlider, SIGNAL(valueChanged(int)), this, SLOT(onVolumeSliderValueChanged()));

          rateBox = new QComboBox(this);
          rateBox->addItem("0.5x", QVariant(0.5));
          rateBox->addItem("1.0x", QVariant(1.0));
          rateBox->addItem("2.0x", QVariant(2.0));
          rateBox->setCurrentIndex(1);

          connect(rateBox, SIGNAL(activated(int)), SLOT(updateRate()));

          QBoxLayout *layout = new QHBoxLayout;
          layout->setMargin(0);
          layout->addWidget(stopButton);
          layout->addWidget(previousButton);
          layout->addWidget(playButton);
          layout->addWidget(nextButton);
          layout->addWidget(muteButton);
          layout->addWidget(volumeSlider);
          layout->addWidget(rateBox);
          setLayout(layout);
      }

      QMediaPlayer::State PlayerControls::state() const
      {
          return playerState;
      }

      void PlayerControls::setState(QMediaPlayer::State state)
      {
          if (state != playerState) {
              playerState = state;

              switch (state) {
              case QMediaPlayer::StoppedState:
                  stopButton->setEnabled(false);
                  playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
                  break;
              case QMediaPlayer::PlayingState:
                  stopButton->setEnabled(true);
                  playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
                  break;
              case QMediaPlayer::PausedState:
                  stopButton->setEnabled(true);
                  playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
                  break;
              }
          }
      }

      int PlayerControls::volume() const
      {
          qreal linearVolume =  QAudio::convertVolume(volumeSlider->value() / qreal(100),
                                                      QAudio::LogarithmicVolumeScale,
                                                      QAudio::LinearVolumeScale);

          return qRound(linearVolume * 100);
      }

      void PlayerControls::setVolume(int volume)
      {
          qreal logarithmicVolume = QAudio::convertVolume(volume / qreal(100),
                                                          QAudio::LinearVolumeScale,
                                                          QAudio::LogarithmicVolumeScale);

          volumeSlider->setValue(qRound(logarithmicVolume * 100));
      }

      bool PlayerControls::isMuted() const
      {
          return playerMuted;
      }

      void PlayerControls::setMuted(bool muted)
      {
          if (muted != playerMuted) {
              playerMuted = muted;

              muteButton->setIcon(style()->standardIcon(muted
                      ? QStyle::SP_MediaVolumeMuted
                      : QStyle::SP_MediaVolume));
          }
      }

      void PlayerControls::playClicked()
      {
          switch (playerState) {
          case QMediaPlayer::StoppedState:
          case QMediaPlayer::PausedState:
              emit play();
              break;
          case QMediaPlayer::PlayingState:
              emit pause();
              break;
          }
      }

      void PlayerControls::muteClicked()
      {
          emit changeMuting(!playerMuted);
      }

      qreal PlayerControls::playbackRate() const
      {
          return rateBox->itemData(rateBox->currentIndex()).toDouble();
      }

      void PlayerControls::setPlaybackRate(float rate)
      {
          for (int i = 0; i < rateBox->count(); ++i) {
              if (qFuzzyCompare(rate, float(rateBox->itemData(i).toDouble()))) {
                  rateBox->setCurrentIndex(i);
                  return;
              }
          }

          rateBox->addItem(QString("%1x").arg(rate), QVariant(rate));
          rateBox->setCurrentIndex(rateBox->count() - 1);
      }

      void PlayerControls::updateRate()
      {
          emit changeRate(playbackRate());
      }

      void PlayerControls::onVolumeSliderValueChanged()
      {
          emit changeVolume(volume());
      }