VS+Qt实现视频播放（载入视频，播放视频，停止，进度条）

PlayerSlider中的代码：

#ifndef PLAYERSLIDER_H
#define PLAYERSLIDER_H

#include <QSlider>
#include <QMouseEvent>
class PlayerSlider : public QSlider
{
	Q_OBJECT
public:
	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

PlayerSlider.cpp中的代码：

#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);
}

VedioPlayer.h中的代码：

#pragma once

#include <QtWidgets/QWidget>
#include "ui_VideoPlayer.h"
#include <QtMultimedia>
#include <QVideoWidget>

class VideoPlayer : public QWidget
{
	Q_OBJECT

public:
	VideoPlayer(QWidget *parent = Q_NULLPTR);
	bool            m_bReLoad;
	public slots:
	void            OnSetMediaFile(void);
	void            OnSlider(qint64);
	void            OnDurationChanged(qint64);
	void            OnStateChanged(QMediaPlayer::State);

private:
	Ui::VideoPlayerClass ui;
	QVideoWidget    *       m_pPlayerWidget;
	QMediaPlayer    *       m_pPlayer;
};

VedioPlayer.cpp中的代码：

#include "VideoPlayer.h"
#include <QFileDialog>
#include "ui_VideoPlayer.h"

VideoPlayer::VideoPlayer(QWidget *parent)
	: QWidget(parent)
{
	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);
	//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)));
}

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);
	//ui.horizontalSlider->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);
	}
}

main.cpp中的代码：

#include "VideoPlayer.h"
#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	VideoPlayer w;
	w.show();
	return a.exec();
}

运行结果：