pro文件：
#-------------------------------------------------###-------------------------------------------------QT += core gui multimedia multimediawidgetsgreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsTARGET = VideoPlayerTEMPLATE = appSOURCES += main.cpp \ videoplayer.cpp \ playerslider.cppHEADERS += \ videoplayer.h \ playerslider.hFORMS += \ videoplayer.ui
main.cpp
#include "videoplayer.h"#include <QApplication>int main(int argc, char argv[]){ QApplication a(argc, argv); VideoPlayer w; w.show(); return a.exec();}
VideoPlayer是我定义的播放器窗体类。它包括一个QMediaplayer,一个QVideoWidget，一个播放按钮，一个停止按钮，一个载入按钮，和进度条PlayerSlider。VideoPlayer的ui文件外观如图：
这里面的PlayerSlider继承自QSlider，行为定义如下：
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#ifndef PLAYERSLIDER_H#define PLAYERSLIDER_H#include <QSlider>#include <QMouseEvent>class PlayerSlider : public QSlider{ Q_OBJECTpublic: PlayerSlider(QWidget parent = 0); void setProgress(qint64);signals: void sigProgress(qint64);private: bool m_bPressed;protected: void mousePressEvent(QMouseEvent ); void mouseMoveEvent(QMouseEvent ); void mouseReleaseEvent(QMouseEvent );};#endif // PLAYERSLIDER_H
#include "playerslider.h"PlayerSlider::PlayerSlider(QWidget parent) : QSlider(parent){ m_bPressed = false;}void PlayerSlider::mousePressEvent(QMouseEvent e){ m_bPressed = true; QSlider::mousePressEvent(e);//必须有这句，否则手动不能移动滑块}void PlayerSlider::mouseMoveEvent(QMouseEvent e){ QSlider::mouseMoveEvent(e);//必须有这句，否则手动不能移动滑块}void PlayerSlider::mouseReleaseEvent(QMouseEvent e){ m_bPressed = false; qint64 i64Pos = value(); emit sigProgress(i64Pos); QSlider::mouseReleaseEvent(e);//必须有这句，否则手动不能移动滑块}void PlayerSlider::setProgress(qint64 i64Progress){ if(!m_bPressed) setValue(i64Progress);}
这个类的作用有3个：1）接收QMediaPlaer发来的进度信息，更新进度条；2）当用户操作进度条时，不再让进度条响应QMediaPlaer发来的进度信息；3）当用户完成对进度条的拖动后，向QMediaPlaer发送播放位置更新信息。
另一个类是VideoPlayer，行为定义如下：
#ifndef VIDEOPLAYER_H#define VIDEOPLAYER_H#include <QWidget>#include <QtMultimedia>#include <QVideoWidget>namespace Ui {class VideoPlayer;}class VideoPlayer : public QWidget{ Q_OBJECTpublic: explicit VideoPlayer(QWidget parent = 0); ~VideoPlayer(); bool m_bReLoad;public slots: void OnSetMediaFile(void); void OnSlider(qint64); void OnDurationChanged(qint64); void OnStateChanged(QMediaPlayer::State);private: QVideoWidget m_pPlayerWidget; QMediaPlayer m_pPlayer; Ui::VideoPlayer ui;};#endif // VIDEOPLAYER_H
#include "videoplayer.h"#include "ui_videoplayer.h"#include <QFileDialog>VideoPlayer::VideoPlayer(QWidget parent) : QWidget(parent), ui(new Ui::VideoPlayer){ ui->setupUi(this); m_pPlayer = new QMediaPlayer; m_pPlayerWidget = new QVideoWidget; m_pPlayer->setVideoOutput(m_pPlayerWidget); ui->verticalLayout->addWidget(m_pPlayerWidget); m_pPlayerWidget->setAutoFillBackground(true); QPalette qplte; qplte.setColor(QPalette::Window, QColor(0,0,0)); m_pPlayerWidget->setPalette(qplte); //载入 connect(ui->BtnLoad, SIGNAL(clicked()), this, SLOT(OnSetMediaFile())); //播放 connect(ui->BtnPlay, SIGNAL(clicked()), m_pPlayer, SLOT(play())); //停止 connect(ui->BtnStop, SIGNAL(clicked()), m_pPlayer, SLOT(stop())); connect(m_pPlayer, SIGNAL(stateChanged(QMediaPlayer::State)), this, SLOT(OnStateChanged(QMediaPlayer::State))); ui->BtnStop->setEnabled(false); //设置滑块行为 m_bReLoad = true; ui->slider->setEnabled(false); connect(m_pPlayer, SIGNAL(positionChanged(qint64)), this, SLOT(OnSlider(qint64))); connect(m_pPlayer, SIGNAL(durationChanged(qint64)), this, SLOT(OnDurationChanged(qint64))); connect(ui->slider, SIGNAL(sigProgress(qint64)), m_pPlayer, SLOT(setPosition(qint64)));}VideoPlayer::~VideoPlayer(){ delete m_pPlayer; delete m_pPlayerWidget; delete ui;}void VideoPlayer::OnSetMediaFile(void){ QFileDialog dialog(this); dialog.setFileMode(QFileDialog::AnyFile); QStringList fileNames; if (dialog.exec()) fileNames = dialog.selectedFiles(); if(!fileNames.empty()) { m_pPlayer->setMedia(QUrl::fromLocalFile(fileNames[0])); m_bReLoad = true; ui->slider->setValue(0); }}void VideoPlayer::OnSlider(qint64 i64Pos){ ui->slider->setProgress(i64Pos);}void VideoPlayer::OnDurationChanged(qint64 i64Duration){ if(i64Duration > 0 && m_bReLoad) { ui->slider->setRange(0, i64Duration); m_bReLoad = false; }}void VideoPlayer::OnStateChanged(QMediaPlayer::State enumState){ if(QMediaPlayer::StoppedState == enumState) { ui->BtnPlay->setEnabled(true); ui->BtnStop->setEnabled(false); ui->slider->setEnabled(false); } else if(QMediaPlayer::PlayingState == enumState) { ui->BtnPlay->setEnabled(false); ui->BtnStop->setEnabled(true); ui->slider->setEnabled(true); }}
之所以在他的构造函数里设置QPalette，是因为假如不这样，在程序启动时，m_pPlayer不是黑色，而是与背景同样的颜色，显得不好看。
显示效果：
