#QT（本地音乐播放器）

1.IDE：QTCreator

2.实验：之前做的音乐播放器只做了一个界面，是因为跟的课程发现到后面需要付费，并且WINGW6.2.0运行QMediaPlayer时无法运行，会崩溃，现在退一步用WINGW5.12.2做一个本地音乐播放器

3.记录：

（1）鼠标悬停，背景颜色改变

（2）listwidget以及水平滑块

（3）双击播放音乐的实现

void Widget::on_listWidget_doubleClicked(const QModelIndex &index)    //双击播放指定音乐
{mediaplayer->setMedia(playlist[index.row()]);mediaplayer->play();
}

（4）打开文件夹的实现

void Widget::on_openfile_pb_clicked()   //打开文件按钮按下
{//QMessageBox::information(this,"文件","打开文件");//打开对话框，让用户选择音乐的存放路径auto path=QFileDialog::getExistingDirectory(this,"选择音乐所在的路径","c:/Users/***/Desktop/music_path");   //打开指定文件夹***涉及个人信息
//    qInfo()<<path;   //打印刚才打开文件夹QDir dir(path);    //auto musiclist=dir.entryList(QStringList()<<"*.mp3"<<"*.wav");  //筛出mp3和wav文件
//  qInfo()<<musiclist;  //打印帅选后的音乐//把筛选出的文件在listwidget显示出来ui->listWidget->addItems(musiclist);//默认选择第一首音乐ui->listWidget->setCurrentRow(0);//把音乐完整路径保存起来for(auto file : musiclist)playlist.append(QUrl::fromLocalFile(path+"/"+file));  //append附加
//    qInfo()<<playlist;   //将附加的音乐列表打印出来
}

（5）播放的实现

void Widget::on_playorpause_pb_clicked()    //播放或者暂停按下
{if(mediaplayer->state()!=QMediaPlayer::PlayingState)  //不处于播放状态{//得到音乐索引int index=ui->listWidget->currentRow();//设置音乐路径mediaplayer->setMedia(playlist[index]);}//判断当前状态switch(mediaplayer->state()){case QMediaPlayer::StoppedState:mediaplayer->play();break;case QMediaPlayer::PausedState:mediaplayer->play();break;  //停止则播放case QMediaPlayer::PlayingState:mediaplayer->pause();break;  //正在播放则暂停//    default:mediaplayer->play();break;}
}

（6）上一首，下一首的实现

void Widget::on_lastsong_pb_clicked()      //上一首
{int index=ui->listWidget->currentRow();if(index==0)    //如果在第一行ui->listWidget->setCurrentRow(ui->listWidget->count()-1);elseui->listWidget->setCurrentRow(index-1);mediaplayer->setMedia(playlist[ui->listWidget->currentRow()]);mediaplayer->play();
}void Widget::on_next_song_pb_clicked()    //下一首
{int index=ui->listWidget->currentRow();if(index == (ui->listWidget->count()-1))  //如果在最后一首歌ui->listWidget->setCurrentRow(0);elseui->listWidget->setCurrentRow(index+1);mediaplayer->setMedia(playlist[ui->listWidget->currentRow()]);mediaplayer->play();
}

（7）获取音乐总时长，当前播放进度，改变当前播放进度，改变音量的实现

    //获取当前文件总播放时间connect(mediaplayer,&QMediaPlayer::durationChanged,this,[=](qint64 duration){ui->total_playtime->setText(QString("%1:%2").arg(duration/1000/60,2,10,QChar('0')).arg(duration/1000%60,2,10,QChar('0')));//2为位宽,10为进制,QChar('0')为填充0ui->play_slider->setRange(0,duration);});//根据进度改变当前播放时间connect(mediaplayer,&QMediaPlayer::positionChanged,this,[=](qint64 position){ui->now_playtime->setText(QString("%1:%2").arg(position/1000/60,2,10,QChar('0')).arg(position/1000%60,2,10,QChar('0')));//2为位宽,10为进制,QChar('0')为填充0ui->play_slider->setValue(position);});//拖动滑块，让音乐进度随滑块改变而改变connect(ui->play_slider,&QSlider::sliderMoved,mediaplayer,&QMediaPlayer::setPosition);//拖动滑块，改变音量connect(ui->volume_slider,&QSlider::sliderMoved,mediaplayer,&QMediaPlayer::setVolume);

（8）总体运行效果

MyMusic 2024-03-08 10-02-19

4.代码

pro

QT       += core gui multimedia widgetsgreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsCONFIG += c++17# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0SOURCES += \main.cpp \widget.cppHEADERS += \widget.hFORMS += \widget.ui# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += targetRESOURCES += \resource.qrc

widget.h

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QPaintEvent>
#include <QMediaPlayer>
QT_BEGIN_NAMESPACE
namespace Ui {
class Widget;
}
QT_END_NAMESPACEclass Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();void paintEvent(QPaintEvent *);
private slots:void on_openfile_pb_clicked();void on_playorpause_pb_clicked();void on_lastsong_pb_clicked();void on_next_song_pb_clicked();void on_listWidget_doubleClicked(const QModelIndex &index);void on_close_pb_clicked();void on_about_pb_clicked();private:Ui::Widget *ui;QMediaPlayer *mediaplayer;QList<QUrl> playlist;     //播放列表
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QPainter>
#include <QMessageBox>   //消息提示
#include <QFileDialog>  //操作文件
#include <QDir>         //操作路径
#include <QDebug>
//#include <QString>
#include <QMediaPlayer>
#include <QAudioOutput>  //音乐输出Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);this->setFixedSize(this->geometry().size());       //设置固定大小this->setWindowFlag(Qt::FramelessWindowHint);      //关闭窗口标题//定义一个媒体播放对象mediaplayer = new QMediaPlayer(this);//设置音量mediaplayer->setVolume(50);//获取当前文件总播放时间connect(mediaplayer,&QMediaPlayer::durationChanged,this,[=](qint64 duration){ui->total_playtime->setText(QString("%1:%2").arg(duration/1000/60,2,10,QChar('0')).arg(duration/1000%60,2,10,QChar('0')));//2为位宽,10为进制,QChar('0')为填充0ui->play_slider->setRange(0,duration);});//根据进度改变当前播放时间connect(mediaplayer,&QMediaPlayer::positionChanged,this,[=](qint64 position){ui->now_playtime->setText(QString("%1:%2").arg(position/1000/60,2,10,QChar('0')).arg(position/1000%60,2,10,QChar('0')));//2为位宽,10为进制,QChar('0')为填充0ui->play_slider->setValue(position);});//拖动滑块，让音乐进度随滑块改变而改变connect(ui->play_slider,&QSlider::sliderMoved,mediaplayer,&QMediaPlayer::setPosition);//拖动滑块，改变音量connect(ui->volume_slider,&QSlider::sliderMoved,mediaplayer,&QMediaPlayer::setVolume);
}Widget::~Widget()
{delete ui;
}void Widget::paintEvent(QPaintEvent*)    //重新定义画布
{QPainter paint(this);paint.drawPixmap(0,0,width(),height(),QPixmap(":image/picture/background.jpg"));
}void Widget::on_openfile_pb_clicked()   //打开文件按钮按下
{//QMessageBox::information(this,"文件","打开文件");//打开对话框，让用户选择音乐的存放路径auto path=QFileDialog::getExistingDirectory(this,"选择音乐所在的路径","c:/Users/***/Desktop/music_path");   //打开指定文件夹
//    qInfo()<<path;   //打印刚才打开文件夹QDir dir(path);    //auto musiclist=dir.entryList(QStringList()<<"*.mp3"<<"*.wav");  //筛出mp3和wav文件
//  qInfo()<<musiclist;  //打印帅选后的音乐//把筛选出的文件在listwidget显示出来ui->listWidget->addItems(musiclist);//默认选择第一首音乐ui->listWidget->setCurrentRow(0);//把音乐完整路径保存起来for(auto file : musiclist)playlist.append(QUrl::fromLocalFile(path+"/"+file));  //append附加
//    qInfo()<<playlist;   //将附加的音乐列表打印出来
}void Widget::on_playorpause_pb_clicked()    //播放或者暂停按下
{if(mediaplayer->state()!=QMediaPlayer::PlayingState)  //不处于播放状态{//得到音乐索引int index=ui->listWidget->currentRow();//设置音乐路径mediaplayer->setMedia(playlist[index]);}//判断当前状态switch(mediaplayer->state()){case QMediaPlayer::StoppedState:mediaplayer->play();break;case QMediaPlayer::PausedState:mediaplayer->play();break;  //停止则播放case QMediaPlayer::PlayingState:mediaplayer->pause();break;  //正在播放则暂停//    default:mediaplayer->play();break;}
}void Widget::on_lastsong_pb_clicked()      //上一首
{int index=ui->listWidget->currentRow();if(index==0)    //如果在第一行ui->listWidget->setCurrentRow(ui->listWidget->count()-1);elseui->listWidget->setCurrentRow(index-1);mediaplayer->setMedia(playlist[ui->listWidget->currentRow()]);mediaplayer->play();
}void Widget::on_next_song_pb_clicked()    //下一首
{int index=ui->listWidget->currentRow();if(index == (ui->listWidget->count()-1))  //如果在最后一首歌ui->listWidget->setCurrentRow(0);elseui->listWidget->setCurrentRow(index+1);mediaplayer->setMedia(playlist[ui->listWidget->currentRow()]);mediaplayer->play();
}void Widget::on_listWidget_doubleClicked(const QModelIndex &index)    //双击播放指定音乐
{mediaplayer->setMedia(playlist[index.row()]);mediaplayer->play();
}void Widget::on_close_pb_clicked()     //离开按钮按下
{close();
}void Widget::on_about_pb_clicked()     //关于按钮按下
{QMessageBox::about(this,"关于","应用：本地音乐播放器\r\n版本：1.0.0.0\r\n制作人：GrassFishStudio\r\n时间：2024年3月7日");
}