基于Qt的简易多媒体播放器

项目描述：嵌入式C++软件编程项目，独立完成基于Qt的简易多媒体播放器；利用Phonon多媒体框架，实现本地多媒体的播放、暂停、停止、音量调节，宽度、色调、饱和度、对比度的调节，播放画面的缩放等功能；熟悉QT下用C++进行图形界面的开发、槽机制的使用。

项目代码地址：

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <phonon>

class QMenu;
class QAction;

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT
    
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    
private slots:
    void createContextMenu();
    void showContextMenu(const QPoint &);
    void aspectChanged(QAction *action);
    void scaleChanged(QAction *action);
    void on_horizontalSlider_valueChanged(int value);
    void on_horizontalSlider_3_valueChanged(int value);
    void on_horizontalSlider_2_valueChanged(int value);
    void on_horizontalSlider_4_valueChanged(int value);

private:
    Ui::Widget *ui;
    Phonon::VideoWidget *videoWidget;
    QMenu *mainMenu;
};

#endif // WIDGET_H

widget。cpp

#include <QMenu>
#include <QAction>
#include <QVBoxLayout>
#include <QToolBar>

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);

    //创建媒体库
    Phonon::MediaObject *mediaObject = new Phonon::MediaObject(this);
    videoWidget = new Phonon::VideoWidget(this);
    Phonon::createPath(mediaObject,videoWidget);

    Phonon::AudioOutput *audioOutput = new Phonon::AudioOutput(Phonon::VideoCategory,this);
    Phonon::createPath(mediaObject,audioOutput);

    mediaObject->setCurrentSource(Phonon::MediaSource("myVideo.mp4"));

    //创建播放进度滑块
    Phonon::SeekSlider *seekSlider = new Phonon::SeekSlider(mediaObject,this);

    //创建工具栏，包含类播放，暂停，停止动作，以及音量控制滑块
    QToolBar *toolBar = new QToolBar(this);
    QAction *playAction = new QAction(style()->standardIcon(QStyle::SP_MediaPlay),tr("播放"),this);
    connect(playAction,SIGNAL(triggered()),mediaObject,SLOT(play()));

    QAction *pauseAction = new QAction(style()->standardIcon(QStyle::SP_MediaPause),tr("暂停"),this);
    connect(pauseAction,SIGNAL(triggered()),mediaObject,SLOT(pause()));

    QAction *stopAction = new QAction(style()->standardIcon(QStyle::SP_MediaStop),tr("停止"),this);
    connect(stopAction,SIGNAL(triggered()),mediaObject,SLOT(stop()));

    Phonon::VolumeSlider *volumeSlider = new Phonon::VolumeSlider(audioOutput,this);
    volumeSlider->setSizePolicy(QSizePolicy::Maximum,QSizePolicy::Maximum);

    toolBar->addAction(playAction);
    toolBar->addAction(pauseAction);
    toolBar->addAction(stopAction);
    toolBar->addWidget(volumeSlider);

    //创建布局管理器，将各个部件都添加到布局管理器中
    QVBoxLayout *mainLayout = new QVBoxLayout;
    videoWidget->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
    mainLayout->addWidget(videoWidget);
    mainLayout->addWidget(seekSlider);
    mainLayout->addWidget(toolBar);
    mainLayout->addWidget(ui->frame);
    setLayout(mainLayout);

    //设置Widget和VideoWidget都使用自定义上下文菜单
    setContextMenuPolicy(Qt::CustomContextMenu);
    videoWidget->setContextMenuPolicy(Qt::CustomContextMenu);
    connect(videoWidget,SIGNAL(customContextMenuRequested(const QPoint &)),SLOT(showContextMenu(const QPoint &)));
    connect(this,SIGNAL(customContextMenuRequested(const QPoint &)),SLOT(showContextMenu(const QPoint &)));

    //创建上下文菜单
    createContextMenu();
}

Widget::~Widget()
{
    delete ui;
}

//更改亮度
void Widget::on_horizontalSlider_valueChanged(int value)
{
    videoWidget->setBrightness(value/10.0);
}

//更改色调
void Widget::on_horizontalSlider_3_valueChanged(int value)
{
    videoWidget->setHue(value/10.0);
}

//更改饱和度
void Widget::on_horizontalSlider_2_valueChanged(int value)
{
    videoWidget->setSaturation(value/10.0);
}

//更改对比度
void Widget::on_horizontalSlider_4_valueChanged(int value)
{
    videoWidget->setContrast(value/10.0);
}

void Widget::createContextMenu()
{
    mainMenu = new QMenu(this);

    //创建"宽高比"子菜单
    QMenu *aspectMenu = mainMenu->addMenu(tr("宽高比"));
    QActionGroup *aspectGroup = new QActionGroup(aspectMenu);
    connect(aspectGroup,SIGNAL(triggered(QAction *)),this,SLOT(aspectChanged(QAction *)));
    aspectGroup->setExclusive(true);

    QAction *aspectActionAuto = aspectMenu->addAction(tr("自动"));
    aspectActionAuto->setCheckable(true);
    aspectActionAuto->setChecked(true);
    aspectGroup->addAction(aspectActionAuto);

    QAction *aspectActionScale = aspectMenu->addAction(tr("缩放"));
    aspectActionScale->setCheckable(true);
    aspectGroup->addAction(aspectActionScale);

    QAction *aspectAction16_9 = aspectMenu->addAction(tr("16:9"));
    aspectAction16_9->setCheckable(true);
    aspectGroup->addAction(aspectAction16_9);

    QAction *aspectAction4_3 = aspectMenu->addAction(tr("4:3"));
    aspectAction4_3->setCheckable(true);
    aspectGroup->addAction(aspectAction4_3);

    //创建"缩放模式"子菜单
    QMenu *scaleMenu = mainMenu->addMenu(tr("缩放模式"));
    QActionGroup *scaleGroup = new QActionGroup(scaleMenu);
    connect(scaleGroup,SIGNAL(triggered(QAction *)),this,SLOT(scaleChanged(QAction *)));
    scaleGroup->setExclusive(true);

    QAction *scaleActionFit = scaleMenu->addAction(tr("保持宽高比"));
    scaleActionFit->setCheckable(true);
    scaleActionFit->setChecked(true);
    scaleGroup->addAction(scaleActionFit);

    QAction *scaleActionCrop = scaleMenu->addAction(tr("缩放和裁剪"));
    scaleActionCrop->setCheckable(true);
    scaleGroup->addAction(scaleActionCrop);

    //创建"全屏"子菜单
    QAction *fullScreenAction = mainMenu->addAction(tr("全屏"));
    fullScreenAction->setCheckable(true);
    connect(fullScreenAction,SIGNAL(triggered(bool)),videoWidget,SLOT(setFullScreen(bool)));

}

//显示上下文菜单
void Widget::showContextMenu(const QPoint &pos)
{
    mainMenu->popup(videoWidget->isFullScreen() ? pos : mapToGlobal(pos));
}

//设置宽高比
void Widget::aspectChanged(QAction *action)
{
    if (action->text() == tr("16:9"))
        videoWidget->setAspectRatio(Phonon::VideoWidget::AspectRatio16_9);
    else if (action->text() == tr("缩放"))
        videoWidget->setAspectRatio(Phonon::VideoWidget::AspectRatioWidget);
    else if (action->text() == tr("4:3"))
        videoWidget->setAspectRatio(Phonon::VideoWidget::AspectRatio4_3);
    else
        videoWidget->setAspectRatio(Phonon::VideoWidget::AspectRatioAuto);
}

//设置缩放模式
void Widget::scaleChanged(QAction *action)
{
    if (action->text() == tr("缩放和裁剪"))
        videoWidget->setScaleMode(Phonon::VideoWidget::ScaleAndCrop);
    else
        videoWidget->setScaleMode(Phonon::VideoWidget::FitInView);
}

man.cpp

#include <QApplication>
#include <QTextCodec>
#include "widget.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    a.setApplicationName("Player");
    QTextCodec::setCodecForTr(QTextCodec::codecForLocale());
    Widget w;
    w.show();
    
    return a.exec();
}