qt实现视频播放器

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qt实现视频播放器

#qt实现视频播放器| 来源: 网络整理| 查看: 265

本篇博客介绍如何利用qMediaPlayer和qvideowidget实现视频文件(avi,mp4….)的播放，并且提供进度显示，还可以通过拖动进度条来变换播放位置。相关代码可以在我的资源里下载”基于qt的视频播放器”

pro文件：

#------------------------------------------------- # # Project created by QtCreator 2018-11-02T20:03:58 # #------------------------------------------------- QT += core gui multimedia multimediawidgets greaterThan(QT_MAJOR_VERSION, 4): QT += widgets TARGET = VideoPlayer TEMPLATE = app SOURCES += main.cpp \ videoplayer.cpp \ playerslider.cpp HEADERS += \ videoplayer.h \ playerslider.h FORMS += \ videoplayer.ui

main.cpp

#include "videoplayer.h" #include 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：

#ifndef PLAYERSLIDER_H #define PLAYERSLIDER_H #include #include 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 #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：

#include "videoplayer.h" #include "ui_videoplayer.h" #include 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。

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qt实现视频播放器

qt实现视频播放器

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