SoundPlayer.cpp

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// ======================================================================
//  SoundPlayer.cpp
// ======================================================================
//                   This file is a part of the book 
//             "Qt 5.10 Professional programming with C++"
//                       http://qt-book.com
// ======================================================================
//  Copyright (c) 2017 by Max Schlee
// ======================================================================

#include <QtWidgets>
#include "SoundPlayer.h"

// ----------------------------------------------------------------------
SoundPlayer::SoundPlayer(QWidget* pwgt/*=0*/) : QWidget(pwgt)
{
    QPushButton* pcmdOpen   = new QPushButton("&Open");
    QDial*       pdiaVolume = new QDial;

    m_pcmdPlay     = new QPushButton;
    m_pcmdStop     = new QPushButton;
    m_psldPosition = new QSlider;
    m_plblCurrent  = new QLabel(msecsToString(0));
    m_plblRemain   = new QLabel(msecsToString(0));
    m_pmp          = new QMediaPlayer;    

    m_pcmdPlay->setEnabled(false);
    m_pcmdPlay->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

    m_pcmdStop->setEnabled(false);
    m_pcmdStop->setIcon(style()->standardIcon(QStyle::SP_MediaStop));

    m_psldPosition->setRange(0, 0);
    m_psldPosition->setOrientation(Qt::Horizontal);

    pdiaVolume->setRange(0, 100);
    int nDefaultVolume = 50;
    m_pmp->setVolume(nDefaultVolume);
    pdiaVolume->setValue(nDefaultVolume);

    connect(pcmdOpen, SIGNAL(clicked()), SLOT(slotOpen()));
    connect(m_pcmdPlay, SIGNAL(clicked()), SLOT(slotPlay()));
    connect(m_pcmdStop, SIGNAL(clicked()), m_pmp, SLOT(stop()));
    connect(pdiaVolume, SIGNAL(valueChanged(int)), 
            m_pmp,      SLOT(setVolume(int))
           );

    connect(m_psldPosition, SIGNAL(sliderMoved(int)), 
            SLOT(slotSetMediaPosition(int))
           );

    connect(m_pmp, SIGNAL(positionChanged(qint64)), 
            SLOT(slotSetSliderPosition(qint64))
           );
    connect(m_pmp, SIGNAL(durationChanged(qint64)), 
            SLOT(slotSetDuration(qint64))
           );
    connect(m_pmp, SIGNAL(stateChanged(QMediaPlayer::State)),
           SLOT(slotStatusChanged(QMediaPlayer::State))
           );

    //Layout setup
    QHBoxLayout* phbxPlayControls = new QHBoxLayout;    
    phbxPlayControls->addWidget(pcmdOpen);
    phbxPlayControls->addWidget(m_pcmdPlay);
    phbxPlayControls->addWidget(m_pcmdStop);
    phbxPlayControls->addWidget(pdiaVolume);

    QHBoxLayout* phbxTimeControls = new QHBoxLayout;    
    phbxTimeControls->addWidget(m_plblCurrent);
    phbxTimeControls->addWidget(m_psldPosition);
    phbxTimeControls->addWidget(m_plblRemain);
    
    m_pvbxMainLayout = new QVBoxLayout;    
    m_pvbxMainLayout->addLayout(phbxPlayControls);
    m_pvbxMainLayout->addLayout(phbxTimeControls);

    setLayout(m_pvbxMainLayout);    
}

// ----------------------------------------------------------------------
void SoundPlayer::slotOpen()
{
    QString strFile = QFileDialog::getOpenFileName(this, 
                                                   "Open File"
                                                  );
    if (!strFile.isEmpty()) {
        m_pmp->setMedia(QUrl::fromLocalFile(strFile));
        m_pcmdPlay->setEnabled(true);
        m_pcmdStop->setEnabled(true);
    }
}

// ----------------------------------------------------------------------
void SoundPlayer::slotPlay()
{
    switch(m_pmp->state()) {
    case QMediaPlayer::PlayingState:
        m_pmp->pause();
        break;
    default:
        m_pmp->play();
        break;
    }
}

// ----------------------------------------------------------------------
void SoundPlayer::slotSetMediaPosition(int n)
{
    m_pmp->setPosition(n);
}

// ----------------------------------------------------------------------
void SoundPlayer::slotSetDuration(qint64 n)
{
    m_psldPosition->setRange(0, n);
    m_plblCurrent->setText(msecsToString(0));
    m_plblRemain->setText(msecsToString(n));
}

// ----------------------------------------------------------------------
void SoundPlayer::slotStatusChanged(QMediaPlayer::State state)
{
    switch(state) {
    case QMediaPlayer::PlayingState:
        m_pcmdPlay->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
        break;
    default:
        m_pcmdPlay->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
        break;
    }
}

// ----------------------------------------------------------------------
void SoundPlayer::slotSetSliderPosition(qint64 n)
{
    m_psldPosition->setValue(n);

    int nDuration = m_psldPosition->maximum();
    m_plblCurrent->setText(msecsToString(n));
    m_plblRemain->setText(msecsToString(nDuration - n));
}

// ----------------------------------------------------------------------
QString SoundPlayer::msecsToString(qint64 n)
{
    int nHours   = (n / (60 * 60 * 1000));
    int nMinutes = ((n  % (60 * 60 * 1000)) / (60 * 1000));
    int nSeconds = ((n % (60 * 1000)) / 1000);

    return QTime(nHours, nMinutes, nSeconds).toString("hh:mm:ss");
}