Qt Charts_Audio实践

这里完全是照搬帮助文档中的代码生成的程序

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工程文件代码

#-------------------------------------------------

#

# Project created by QtCreator 2017-02-06T13:52:31

#

#-------------------------------------------------

QT       += core gui

QT       += charts multimedia

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = qchart_Audio_Project

TEMPLATE = app

DEFINES += QT_DEPRECATED_WARNINGS

SOURCES += main.cpp\

        widget.cpp \

    xyseriesiodevice.cpp

HEADERS  += widget.h \

    xyseriesiodevice.h

FORMS    += widget.ui

target.path = $$[QT_INSTALL_EXAMPLES]/charts/audio

INSTALLS += target

widget.h文件代码

#ifndef WIDGET_H

#define WIDGET_H

#include <QWidget>

#include <QtCharts/QChartGlobal>

namespace Ui {

class Widget;

}

QT_CHARTS_BEGIN_NAMESPACE

class QLineSeries;

class QChart;

QT_CHARTS_END_NAMESPACE

QT_CHARTS_USE_NAMESPACE

class XYSeriesIODevice;

class QAudioInput;

class Widget : public QWidget

{

    Q_OBJECT

public:

    explicit Widget(QWidget *parent = 0);

    ~Widget();

private:

    Ui::Widget *ui;

    XYSeriesIODevice *m_device;

    QChart *m_chart;

    QLineSeries *m_series;

    QAudioInput *m_audioInput;

};

#endif // WIDGET_H

widget.cpp代码

#include "widget.h"

#include <QtMultimedia/QAudioDeviceInfo>

#include <QtMultimedia/QAudioInput>

#include <QtMultimedia/QAudioFormat>

#include <QtCharts/QChartView>

#include <QtCharts/QLineSeries>

#include <QtCharts/QChart>

#include <QtWidgets/QVBoxLayout>

#include <QtCharts/QValueAxis>

#include "xyseriesiodevice.h"

#include "ui_widget.h"

QT_CHARTS_USE_NAMESPACE

Widget::Widget(QWidget *parent) :

    QWidget(parent),m_device(0),

    m_chart(0),

    m_series(0),

    m_audioInput(0),

    ui(new Ui::Widget)

{

    ui->setupUi(this);

    m_chart = new QChart;

    QChartView *chartView = new QChartView(m_chart);

    chartView->setMinimumSize(800, 600);

    m_series = new QLineSeries;

    m_chart->addSeries(m_series);

    QValueAxis *axisX = new QValueAxis;

    axisX->setRange(0, 2000);

    axisX->setLabelFormat("%g");

    axisX->setTitleText("Samples");

    QValueAxis *axisY = new QValueAxis;

    axisY->setRange(-1, 1);

    axisY->setTitleText("Audio level");

    m_chart->setAxisX(axisX, m_series);

    m_chart->setAxisY(axisY, m_series);

    m_chart->legend()->hide();

    m_chart->setTitle("Data from the microphone");

    QVBoxLayout *mainLayout = new QVBoxLayout;

    mainLayout->addWidget(chartView);

    setLayout(mainLayout);

    QAudioFormat formatAudio;

    formatAudio.setSampleRate(8000);

    formatAudio.setChannelCount(1);

    formatAudio.setSampleSize(8);

    formatAudio.setCodec("audio/pcm");

    formatAudio.setByteOrder(QAudioFormat::LittleEndian);

    formatAudio.setSampleType(QAudioFormat::UnSignedInt);

    QAudioDeviceInfo inputDevices = QAudioDeviceInfo::defaultInputDevice();

    m_audioInput = new QAudioInput(inputDevices,formatAudio, this);

    m_device = new XYSeriesIODevice(m_series, this);

    m_device->open(QIODevice::WriteOnly);

    m_audioInput->start(m_device);

}

Widget::~Widget()

{

    m_audioInput->stop();

    m_device->close();

    delete ui;

}

xyseriesiodevice.h代码

#ifndef XYSERIESIODEVICE_H

#define XYSERIESIODEVICE_H

#include <QtCore/QIODevice>

#include <QtCharts/QChartGlobal>

QT_CHARTS_BEGIN_NAMESPACE

class QXYSeries;

QT_CHARTS_END_NAMESPACE

QT_CHARTS_USE_NAMESPACE

class XYSeriesIODevice : public QIODevice

{

    Q_OBJECT

public:

    explicit XYSeriesIODevice(QXYSeries * series, QObject *parent = 0);

protected:

    qint64 readData(char * data, qint64 maxSize);

    qint64 writeData(const char * data, qint64 maxSize);

private:

    QXYSeries *m_series;

};

#endif // XYSERIESIODEVICE_H

xyseriesiodevice.cpp代码

#include "xyseriesiodevice.h"

#include <QtCharts/QXYSeries>

XYSeriesIODevice::XYSeriesIODevice(QXYSeries * series, QObject *parent) :

    QIODevice(parent),

    m_series(series)

{

}

qint64 XYSeriesIODevice::readData(char * data, qint64 maxSize)

{

    Q_UNUSED(data)

    Q_UNUSED(maxSize)

    return -1;

}

qint64 XYSeriesIODevice::writeData(const char * data, qint64 maxSize)

{

    qint64 range = 2000;

    QVector<QPointF> oldPoints = m_series->pointsVector();

    QVector<QPointF> points;

    int resolution = 4;

    if (oldPoints.count() < range) {

        points = m_series->pointsVector();

    } else {

        for (int i = maxSize/resolution; i < oldPoints.count(); i++)

            points.append(QPointF(i - maxSize/resolution, oldPoints.at(i).y()));

    }

    qint64 size = points.count();

    for (int k = 0; k < maxSize/resolution; k++)

        points.append(QPointF(k + size, ((quint8)data[resolution * k] - 128)/128.0));

    m_series->replace(points);

    return maxSize;

}