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Qt: GIF图片播放器（QMovie类）

　
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简介：

QMovie Class

The QMovie class is a convenience class for playing movies with QImageReader. 

Header:

#include <QMovie>

qmake:

QT += gui

Inherits:

QObject


QMovie类用来显示简单的并且没有声音的动画，比如GIF格式的图片等。

如果你想要显示视频或者多媒体，可以使用Qt Multimedia 多媒体框架。


显示一个简单的动画，常用的方式如下：

 QLabel label;
 QMovie *movie = new QMovie("animations/fire.gif");

 label.setMovie(movie);
 movie->start();

实例：

运行效果：

主要代码：

（基类为QWidget）


1. movieplayer.h

/*movieplayer.h*/

#ifndef MOVIEPLAYER_H
#define MOVIEPLAYER_H

#include <QCheckBox>
#include <QGridLayout>
#include <QHBoxLayout>
#include <QLabel>
#include <QMovie>
#include <QSlider>
#include <QSpinBox>
#include <QToolButton>
#include <QVBoxLayout>

#include <QWidget>

class QCheckBox;
class QGridLayout;
class QHBoxLayout;
class QLabel;
class QMovie;
class QSlider;
class QSpinBox;
class QToolButton;
class QVBoxLayout;

class MoviePlayer : public QWidget
{
    Q_OBJECT

public:
    MoviePlayer(QWidget *parent = 0);
    void openFile(const QString &fileName);

private slots:
    void open();
    void goToFrame(int frame);
    void fitToWindow();
    void updateButtons();
    void updateFrameSlider();

private:
    void createControls();
    void createButtons();

    QString currentMovieDirectory;
    QLabel *movieLabel;
    QMovie *movie;
    QToolButton *openButton;
    QToolButton *playButton;
    QToolButton *pauseButton;
    QToolButton *stopButton;
    QToolButton *quitButton;
    QCheckBox *fitCheckBox;
    QSlider *frameSlider;
    QSpinBox *speedSpinBox;
    QLabel *frameLabel;
    QLabel *speedLabel;

    QGridLayout *controlsLayout;
    QHBoxLayout *buttonsLayout;
    QVBoxLayout *mainLayout;
};

#endif

2. movieplayer.cpp

/*movieplayer.cpp*/

#include <QtGui>
#include <QString>
#include <QStyle>
#include <QFileDialog>


#include "movieplayer.h"

MoviePlayer::MoviePlayer(QWidget *parent)
    : QWidget(parent)
{
    movie = new QMovie(this);
    movie->setCacheMode(QMovie::CacheAll);

    movieLabel = new QLabel(tr("No movie loaded"));
    movieLabel->setAlignment(Qt::AlignCenter);
    movieLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    movieLabel->setBackgroundRole(QPalette::Shadow);
    movieLabel->setAutoFillBackground(true);

    currentMovieDirectory = ".gif";

    createControls();
    createButtons();

    connect(movie, SIGNAL(frameChanged(int)), this, SLOT(updateFrameSlider()));
    connect(movie, SIGNAL(stateChanged(QMovie::MovieState)),
            this, SLOT(updateButtons()));
    connect(fitCheckBox, SIGNAL(clicked()), this, SLOT(fitToWindow()));
    connect(frameSlider, SIGNAL(valueChanged(int)), this, SLOT(goToFrame(int)));
    connect(speedSpinBox, SIGNAL(valueChanged(int)),
            movie, SLOT(setSpeed(int)));

    mainLayout = new QVBoxLayout;
    mainLayout->addWidget(movieLabel);
    mainLayout->addLayout(controlsLayout);
    mainLayout->addLayout(buttonsLayout);
    setLayout(mainLayout);

    updateFrameSlider();
    updateButtons();

    setWindowTitle(tr("Movie Player"));
    resize(400, 400);
}

void MoviePlayer::open()
{
    QString fileName = QFileDialog::getOpenFileName(this, tr("Open a Movie"),
                                                    currentMovieDirectory);
    if (!fileName.isEmpty())
        openFile(fileName);
}

void MoviePlayer::openFile(const QString &fileName)
{
    currentMovieDirectory = QFileInfo(fileName).path();

    movie->stop();
    movieLabel->setMovie(movie);
    movie->setFileName(fileName);
    movie->start();

    updateFrameSlider();
    updateButtons();
}

void MoviePlayer::goToFrame(int frame)
{
    movie->jumpToFrame(frame);
}

void MoviePlayer::fitToWindow()
{
    movieLabel->setScaledContents(fitCheckBox->isChecked());
}

void MoviePlayer::updateFrameSlider()
{
    bool hasFrames = (movie->currentFrameNumber() >= 0);

    if (hasFrames)
    {
        if (movie->frameCount() > 0)
        {
            frameSlider->setMaximum(movie->frameCount() - 1);
        }
        else
        {
            if (movie->currentFrameNumber() > frameSlider->maximum())
                frameSlider->setMaximum(movie->currentFrameNumber());
        }
        frameSlider->setValue(movie->currentFrameNumber());
    }
    else
    {
        frameSlider->setMaximum(0);
    }
    frameLabel->setEnabled(hasFrames);
    frameSlider->setEnabled(hasFrames);
}

void MoviePlayer::updateButtons()
{
    playButton->setEnabled(movie->isValid() && movie->frameCount() != 1
            && movie->state() == QMovie::NotRunning);
    pauseButton->setEnabled(movie->state() != QMovie::NotRunning);
    pauseButton->setChecked(movie->state() == QMovie::Paused);
    stopButton->setEnabled(movie->state() != QMovie::NotRunning);
}

void MoviePlayer::createControls()
{
    fitCheckBox = new QCheckBox(tr("Fit to Window"));

    frameLabel = new QLabel(tr("Current frame:"));

    frameSlider = new QSlider(Qt::Horizontal);
    frameSlider->setTickPosition(QSlider::TicksBelow);
    frameSlider->setTickInterval(10);

    speedLabel = new QLabel(tr("Speed:"));

    speedSpinBox = new QSpinBox;
    speedSpinBox->setRange(1, 9999);
    speedSpinBox->setValue(100);
    speedSpinBox->setSuffix(tr("%"));

    controlsLayout = new QGridLayout;   //格子布局
    controlsLayout->addWidget(fitCheckBox, 0, 0, 1, 2);
    controlsLayout->addWidget(frameLabel, 1, 0);
    controlsLayout->addWidget(frameSlider, 1, 1, 1, 2);
    controlsLayout->addWidget(speedLabel, 2, 0);
    controlsLayout->addWidget(speedSpinBox, 2, 1);
}

void MoviePlayer::createButtons()   //按钮水平布局
{
    QSize iconSize(36, 36);

    openButton = new QToolButton;
    openButton->setIcon(style()->standardIcon(QStyle::SP_DialogOpenButton));
    openButton->setIconSize(iconSize);
    openButton->setToolTip(tr("Open File"));
    connect(openButton, SIGNAL(clicked()), this, SLOT(open()));

    playButton = new QToolButton;
    playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
    playButton->setIconSize(iconSize);
    playButton->setToolTip(tr("Play"));
    connect(playButton, SIGNAL(clicked()), movie, SLOT(start()));

    pauseButton = new QToolButton;
    pauseButton->setCheckable(true);
    pauseButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
    pauseButton->setIconSize(iconSize);
    pauseButton->setToolTip(tr("Pause"));
    connect(pauseButton, SIGNAL(clicked(bool)), movie, SLOT(setPaused(bool)));

    stopButton = new QToolButton;
    stopButton->setIcon(style()->standardIcon(QStyle::SP_MediaStop));
    stopButton->setIconSize(iconSize);
    stopButton->setToolTip(tr("Stop"));
    connect(stopButton, SIGNAL(clicked()), movie, SLOT(stop()));

    quitButton = new QToolButton;
    quitButton->setIcon(style()->standardIcon(QStyle::SP_DialogCloseButton));
    quitButton->setIconSize(iconSize);
    quitButton->setToolTip(tr("Quit"));
    connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));

    buttonsLayout = new QHBoxLayout;
    buttonsLayout->addStretch();
    buttonsLayout->addWidget(openButton);
    buttonsLayout->addWidget(playButton);
    buttonsLayout->addWidget(pauseButton);
    buttonsLayout->addWidget(stopButton);
    buttonsLayout->addWidget(quitButton);
    buttonsLayout->addStretch();
}

3. main.cpp

/*main.cpp*/

#include <QApplication>
#include "movieplayer.h"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    MoviePlayer player;
    player.show();

    return app.exec();
}


动态效果图：

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原文链接：Qt: GIF图片播放器（QMovie类），转载请注明来源！

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