qt-everywhere-src-5.14.1/qtmultimedia/examples/multimedia/radio/radio.cpp

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#include "radio.h"

Radio::Radio()
{
    radio = new QRadioTuner;
    connect(radio, QOverload<QRadioTuner::Error>::of(&QRadioTuner::error),
            this, QOverload<QRadioTuner::Error>::of(&Radio::error));

    if (radio->isBandSupported(QRadioTuner::FM))
        radio->setBand(QRadioTuner::FM);

    QWidget *window = new QWidget;
    QVBoxLayout *layout = new QVBoxLayout;
    QHBoxLayout *buttonBar = new QHBoxLayout;
    QHBoxLayout *topBar = new QHBoxLayout;

    layout->addLayout(topBar);

    freq = new QLabel;
    freq->setText(QString("%1 kHz").arg(radio->frequency()/1000));
    topBar->addWidget(freq);
    connect(radio, &QRadioTuner::frequencyChanged,
            this, &Radio::freqChanged);

    signal = new QLabel;
    if (radio->isAvailable())
        signal->setText(tr("No Signal"));
    else
        signal->setText(tr("No radio found"));
    topBar->addWidget(signal);
    connect(radio, &QRadioTuner::signalStrengthChanged,
            this, &Radio::signalChanged);

    volumeSlider = new QSlider(Qt::Vertical,this);
    volumeSlider->setRange(0, 100);
    volumeSlider->setValue(50);
    connect(volumeSlider, &QSlider::valueChanged,
            this, &Radio::updateVolume);
    topBar->addWidget(volumeSlider);

    layout->addLayout(buttonBar);

    searchLeft = new QPushButton;
    searchLeft->setText(tr("scan Down"));
    connect(searchLeft, &QPushButton::clicked,
            this, &Radio::searchDown);
    buttonBar->addWidget(searchLeft);

    left = new QPushButton;
    left->setText(tr("Freq Down"));
    connect(left, &QPushButton::clicked,
            this, &Radio::freqDown);
    buttonBar->addWidget(left);

    right = new QPushButton;
    connect(right, &QPushButton::clicked,
            this, &Radio::freqUp);
    right->setText(tr("Freq Up"));
    buttonBar->addWidget(right);

    searchRight = new QPushButton;
    searchRight->setText(tr("scan Up"));
    connect(searchRight, &QPushButton::clicked,
            this, &Radio::searchUp);
    buttonBar->addWidget(searchRight);

    window->setLayout(layout);
    setCentralWidget(window);
    window->show();

    radio->start();
}

Radio::~Radio()
{
}

void Radio::freqUp()
{
    int f = radio->frequency();
    f += radio->frequencyStep(QRadioTuner::FM);
    radio->setFrequency(f);
}

void Radio::freqDown()
{
    int f = radio->frequency();
    f -= radio->frequencyStep(QRadioTuner::FM);
    radio->setFrequency(f);
}

void Radio::searchUp()
{
    radio->searchForward();
}

void Radio::searchDown()
{
    radio->searchBackward();
}

void Radio::freqChanged(int)
{
    freq->setText(QString("%1 kHz").arg(radio->frequency()/1000));
}

void Radio::signalChanged(int)
{
    if(radio->signalStrength() > 25)
        signal->setText(tr("Got Signal"));
    else
        signal->setText(tr("No Signal"));
}

void Radio::updateVolume(int v)
{
    radio->setVolume(v);
}

void Radio::error(QRadioTuner::Error error)
{
    const QMetaObject *metaObj = radio->metaObject();
    QMetaEnum errorEnum = metaObj->enumerator(metaObj->indexOfEnumerator("Error"));
    qWarning().nospace() << "Warning: Example application received error QRadioTuner::" << errorEnum.valueToKey(error);
}