qtmultimedia/examples/slideshow/slideshow.cpp

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#include "slideshow.h"

#include <qmediaservice.h>
#include <qmediaplaylist.h>
#include <qvideowidget.h>

#include <QtWidgets>

SlideShow::SlideShow(QWidget *parent)
    : QMainWindow(parent)
    , imageViewer(0)
    , playlist(0)
    , statusLabel(0)
    , countdownLabel(0)
    , playAction(0)
    , stopAction(0)
{
    imageViewer = new QMediaImageViewer(this);

    connect(imageViewer, SIGNAL(stateChanged(QMediaImageViewer::State)),
            this, SLOT(stateChanged(QMediaImageViewer::State)));
    connect(imageViewer, SIGNAL(mediaStatusChanged(QMediaImageViewer::MediaStatus)),
            this, SLOT(statusChanged(QMediaImageViewer::MediaStatus)));
    connect(imageViewer, SIGNAL(elapsedTimeChanged(int)), this, SLOT(elapsedTimeChanged(int)));

    playlist = new QMediaPlaylist;
    imageViewer->bind(playlist);

    connect(playlist, SIGNAL(loaded()), this, SLOT(playlistLoaded()));
    connect(playlist, SIGNAL(loadFailed()), this, SLOT(playlistLoadFailed()));

    QVideoWidget *videoWidget = new QVideoWidget;
    imageViewer->setVideoOutput(videoWidget);

    menuBar()->addAction(tr("Open Directory..."), this, SLOT(openDirectory()));
    menuBar()->addAction(tr("Open Playlist..."), this, SLOT(openPlaylist()));

    toolBar = new QToolBar;
    toolBar->setMovable(false);
    toolBar->setFloatable(false);
    toolBar->setEnabled(false);

    toolBar->addAction(
            style()->standardIcon(QStyle::SP_MediaSkipBackward),
            tr("Previous"),
            playlist,
            SLOT(previous()));
    stopAction = toolBar->addAction(
            style()->standardIcon(QStyle::SP_MediaStop), tr("Stop"), imageViewer, SLOT(stop()));
    playAction = toolBar->addAction(
            style()->standardIcon(QStyle::SP_MediaPlay), tr("Play"), this, SLOT(play()));
    toolBar->addAction(
            style()->standardIcon(QStyle::SP_MediaSkipForward), tr("Next"), playlist, SLOT(next()));

    addToolBar(Qt::BottomToolBarArea, toolBar);

    statusLabel = new QLabel(tr("%1 Images").arg(0));
    statusLabel->setAlignment(Qt::AlignCenter);

    countdownLabel = new QLabel;
    countdownLabel->setAlignment(Qt::AlignRight);

    statusBar()->addPermanentWidget(statusLabel, 1);
    statusBar()->addPermanentWidget(countdownLabel);

    setCentralWidget(videoWidget);
}

void SlideShow::openPlaylist()
{
    QString path = QFileDialog::getOpenFileName(this);

    if (!path.isEmpty()) {
        playlist->clear();
        playlist->load(QUrl::fromLocalFile(path));
    }
}

void SlideShow::openDirectory()
{
    QString path = QFileDialog::getExistingDirectory(this);

    if (!path.isEmpty()) {
        playlist->clear();

        QDir dir(path);

        foreach (const QString &fileName, dir.entryList(QDir::Files))
            playlist->addMedia(QUrl::fromLocalFile(dir.absoluteFilePath(fileName)));

        statusChanged(imageViewer->mediaStatus());

        toolBar->setEnabled(playlist->mediaCount() > 0);
    }
}

void SlideShow::play()
{
    switch (imageViewer->state()) {
    case QMediaImageViewer::StoppedState:
    case QMediaImageViewer::PausedState:
        imageViewer->play();
        break;
    case QMediaImageViewer::PlayingState:
        imageViewer->pause();
        break;
    }
}

void SlideShow::stateChanged(QMediaImageViewer::State state)
{
    switch (state) {
    case QMediaImageViewer::StoppedState:
        stopAction->setEnabled(false);
        playAction->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
        break;
    case QMediaImageViewer::PlayingState:
        stopAction->setEnabled(true);
        playAction->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
        break;
    case QMediaImageViewer::PausedState:
        stopAction->setEnabled(true);
        playAction->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
        break;
    }
}

void SlideShow::statusChanged(QMediaImageViewer::MediaStatus status)
{
    switch (status) {
    case QMediaImageViewer::NoMedia:
        statusLabel->setText(tr("%1 Images").arg(playlist->mediaCount()));
        break;
    case QMediaImageViewer::LoadingMedia:
        statusLabel->setText(tr("Image %1 of %2\nLoading...")
                .arg(playlist->currentIndex())
                .arg(playlist->mediaCount()));
        break;
    case QMediaImageViewer::LoadedMedia:
        statusLabel->setText(tr("Image %1 of %2")
                .arg(playlist->currentIndex())
                .arg(playlist->mediaCount()));
        break;
    case QMediaImageViewer::InvalidMedia:
        statusLabel->setText(tr("Image %1 of %2\nInvalid")
                .arg(playlist->currentIndex())
                .arg(playlist->mediaCount()));
        break;
    default:
        break;
    }
}

void SlideShow::playlistLoaded()
{
    statusChanged(imageViewer->mediaStatus());

    toolBar->setEnabled(playlist->mediaCount() > 0);
}

void SlideShow::playlistLoadFailed()
{
    statusLabel->setText(playlist->errorString());

    toolBar->setEnabled(false);
}

void SlideShow::elapsedTimeChanged(int time)
{
    const int remaining = (imageViewer->timeout() - time) / 1000;

    countdownLabel->setText(tr("%1:%2")
            .arg(remaining / 60, 2, 10, QLatin1Char('0'))
            .arg(remaining % 60, 2, 10, QLatin1Char('0')));
}