[C++知识库]QT——制作简易音频播放器

?? ?应用前提：只需要从阿里云数据库中读取选定的某一条实验数据的音频(.wav)，现在的测试版本只是播放本地音频，所以做的这个音频播放器只有6个功能：播放、暂停、音量条、静音、进度条、显示当前播放进度的时间，丑是丑了点但能满足需求。

?? ?接下来详细说一下是怎么实现的。

? ? 先创建新的项目，选择Qt Widget Application，名称我的是AudioDemo4，选择MSVC2017 32bit编译(实验室项目需求)，类名我的是Music，基类选择QWidget，界面创不创建都可以，我创建了。至于上图中的播放、暂停、滑块、静音图标都是从阿里巴巴矢量图标库(iconfont-阿里巴巴矢量图标库)下载的。右键AudioDemo4项目，添加新文件，选择Qt的Qt Resource File，起名为my，先添加前缀(我改为了/)，再添加图标，整个项目目录如下图所示。

在Qt中实现音频播放器需要用到QMediaPlayer，因此需要在AudioDemo4.cpp里加上这句代码：

?music.h：

#ifndef MUSIC_H
#define MUSIC_H

#include <QWidget>
#include <QDebug>
#include <QCursor>
#include <QPushButton>
#include <QSlider>
#include <QMediaPlayer>
#include <QTimer>
#include <QMessageBox>
#include <QSqlDatabase>
#include <QLabel>
#include <QTime>
#include <QMediaPlaylist>

#define HOSTNAME "自己云数据库的地址"
#define DATABASE_NAME "数据库名"
#define USERNAME "用户名"
#define PASSWORD "密码"

namespace Ui {
class Music;
}

class Music : public QWidget
{
    Q_OBJECT

public:
    explicit Music(QWidget *parent = 0);
    ~Music();

    QPushButton *playBtn;       //播放按钮
    QPushButton *volumeBtn;     //音量按钮
    QSlider *seekSlider;        //进度条
    QSlider *volumeSlider;      //音量条
    QMediaPlayer *player;       //播放器
    QLabel *showPro;       //展示进度
    QPalette pac;       //小部件的调色板
    int moved;

    void DatabaseConnection();
    void init_styleSheet();

private:
    Ui::Music *ui;

    QSqlDatabase db;

public slots:
    void playControl();     //播放控制
    void muteControl();     //静音控制
    void VolumeChange(int);    //音量控制
    void positionChange(qint64 position);   //滑块位置随音频进度改变
    void seekChange(int position);      //滑块位置控制音频进度
};

#endif // MUSIC_H

?music.cpp：

#include "music.h"
#include "ui_music.h"

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

    moved = 0;

    player = new QMediaPlayer(this);        //QMediaplayer用于解析音频文件和视频文件

    init_styleSheet();

    connect(playBtn, SIGNAL(clicked(bool)), this, SLOT(playControl()));
    connect(volumeBtn, SIGNAL(clicked(bool)), this, SLOT(muteControl()));
    connect(volumeSlider, SIGNAL(sliderMoved(int)), SLOT(VolumeChange(int)));
    connect(player,SIGNAL(positionChanged(qint64)),this,SLOT(positionChange(qint64)));
    connect(seekSlider,SIGNAL(sliderMoved(int)), this,SLOT(seekChange(int)));
}

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

//连接数据库
void Music::DatabaseConnection(){
    db = QSqlDatabase::addDatabase("QMYSQL");
    db.setHostName(HOSTNAME);
    db.setDatabaseName(DATABASE_NAME);
    db.setUserName(USERNAME);
    db.setPassword(PASSWORD);
    if(!db.open()){
        QMessageBox messageBox(QMessageBox::Information, QString::fromUtf8("数据库异常"), QString::fromUtf8("连接远程数据库失败"), QMessageBox::Yes, NULL);
        switch (messageBox.exec()) {
            case QMessageBox::Yes:
            messageBox.close();
            break;
        default:
            break;
        }
    }
    else
        qDebug()<<"database connection success!";
}

//设置基本样式
void Music::init_styleSheet(){
    //播放按钮
    playBtn = new QPushButton(this);        //创建对象
    playBtn->setObjectName(tr("playBtn"));  //对象名(要改变样式表必须先设置对象名)
    playBtn->setGeometry(30,34,32,32);        //坐标、宽高
    playBtn->setCursor(Qt::PointingHandCursor);     //鼠标悬浮时为手型
    playBtn->setStyleSheet(
                "QPushButton:hover{border-image: url(:/images/play.png)}"
                "QPushButton:!hover{border-image: url(:/images/play.png)}"
                           );

    //音量按钮
    volumeBtn = new QPushButton(this);
    volumeBtn->setObjectName(tr("volumeBtn"));
    volumeBtn->setGeometry(360,80,20,20);
    volumeBtn->setCursor(Qt::PointingHandCursor);
    volumeBtn->setStyleSheet(
                "QPushButton:hover{border-image: url(:/images/sound.png)}"
                "QPushButton:!hover{border-image: url(:/images/sound.png)}"
                           );

    //进度条
    seekSlider = new QSlider(Qt::Horizontal,this);      //水平进度条
    seekSlider->setObjectName(tr("seekSlider"));
    seekSlider->setGeometry(80,36,250,30);
    seekSlider->setCursor(Qt::PointingHandCursor);
    seekSlider->setStyleSheet(
                "QSlider::groove:horizontal{border: 1px solid #999999; height: 2px;}"       //进度条
                "QSlider::handle:horizontal{border: 0px; border-image: url(:/images/circle.png); width: 15px; margin: -7px -7px -7px -1px;}"    //进度条上的滑动轮
                "QSlider::add-page:horizontal{background: qlineargradient(spread:pad, x1:0, y1:1, x2:0, y2:0, stop:0 #bcbcbc, stop:0.25 #bcbcbc, stop:0.5 #bcbcbc, stop:1 #bcbcbc);}"   //还没划过的地方
                "QSlider::sub-page:horizontal{background: qlineargradient(spread:pad, x1:0, y1:1, x2:0, y2:0, stop:0 #439cf3, stop:0.25 #439cf3, stop:0.5 #439cf3, stop:1 #439cf3);}"   //已经划过的地方
                );

    //音量条
    volumeSlider = new QSlider(Qt::Vertical,this);      //垂直进度条
    volumeSlider->setObjectName(tr("seekSlider"));
    volumeSlider->setGeometry(360,10,20,70);
    volumeSlider->setCursor(Qt::PointingHandCursor);
    volumeSlider->setRange(0,100);  //上下限
    volumeSlider->setValue(50);     //初始值

    //进度时间展示
    showPro = new QLabel(this);
    showPro->setGeometry(0,0,50,20);
    showPro->setFont(QFont("Times",10,QFont::Bold));
    pac.setColor(QPalette::WindowText,QColor(70,80,70));
    showPro -> setPalette(pac);
    QTime mov(0,0,0);
    showPro ->setText(mov.toString("mm:ss"));
}

//播放控制
void Music::playControl(){
    if(player->state() == QMediaPlayer::PlayingState){      //当前为播放模式
        player->pause();    //设置播放模式为暂停
        playBtn->setStyleSheet("QPushButton:!hover{border-image: url(:/images/play.png)}"      //改变播放按钮背景图
                                 "QPushButton:hover{border-image: url(:/images/play.png)}"
                                 "QPushButton:pressed{border-image: url(:/images/play.png)}"
                                 );
    }else{      //当前为暂停模式
        player->setMedia(QUrl::fromLocalFile("C:/Users/admin/Desktop/test/01.wav"));
        player->setVolume(50);
        player->play();     //播放
        playBtn->setStyleSheet("QPushButton:!hover{border-image: url(:/images/pause.png)}"
                                 "QPushButton:hover{border-image: url(:/images/pause.png)}"
                                 "QPushButton:pressed{border-image: url(:/images/pause.png)}"
                                 );
    }
}

//静音控制
void Music::muteControl(){
    static bool flag = true;    //判断是否已点击
    if(flag){
        volumeBtn->setStyleSheet("QPushButton:!hover{border-image: url(:/images/sound_close.png)}"
                                 "QPushButton:hover{border-image: url(:/images/sound_close.png)}"
                                 "QPushButton:pressed{border-image: url(:/images/sound_close.png)}"
                                 );
        player -> setMuted(true);
    }else{
        volumeBtn->setStyleSheet("QPushButton:!hover{border-image: url(:/images/sound.png)}"
                                 "QPushButton:hover{border-image: url(:/images/sound.png)}"
                                 "QPushButton:pressed{border-image: url(:/images/sound.png)}"
                                 );
        player -> setMuted(false);
    }
    flag=!flag;
}

//音量控制
void Music::VolumeChange(int vol){
    player -> setVolume(vol);       //将滑块移动值设置为音量
}

//滑块位置随音频进度改变
void Music::positionChange(qint64 position){
    seekSlider->setMaximum(player->duration());      //设置滑块长度
    seekSlider->setValue(position);      //滑块位置随音频进度改变
    moved = position;
    QTime moveTime(0,(moved/60000) % 60,(moved / 1000) % 60);
    showPro ->setText(moveTime.toString("mm:ss"));
    if(seekSlider->value() == player->duration()){      //当滑块的当前值等于音频总时长时改变播放按钮图标
        playBtn->setStyleSheet("QPushButton:!hover{border-image: url(:/images/play.png)}"      //改变播放按钮背景图
                                 "QPushButton:hover{border-image: url(:/images/play.png)}"
                                 "QPushButton:pressed{border-image: url(:/images/play.png)}"
                                 );
        seekSlider->setValue(0);        //播完后滑块回位0
    }
}

//滑块位置控制音频进度
void Music::seekChange(int position){
    player -> setPosition(position);
    moved = position;
    QTime moveTime(0,(moved/60000) % 60,(moved / 1000) % 60);
    showPro ->setText(moveTime.toString("mm:ss"));
}