audioinput.h Example File

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 #ifndef AUDIOINPUT_H
 #define AUDIOINPUT_H

 #include <QAudioInput>
 #include <QByteArray>
 #include <QComboBox>
 #include <QMainWindow>
 #include <QObject>
 #include <QPixmap>
 #include <QPushButton>
 #include <QSlider>
 #include <QWidget>
 #include <QScopedPointer>

 class AudioInfo : public QIODevice
 {
     Q_OBJECT

 public:
     AudioInfo(const QAudioFormat &format);

     void start();
     void stop();

     qreal level() const { return m_level; }

     qint64 readData(char *data, qint64 maxlen) override;
     qint64 writeData(const char *data, qint64 len) override;

 private:
     const QAudioFormat m_format;
     quint32 m_maxAmplitude = 0;
     qreal m_level = 0.0; // 0.0 <= m_level <= 1.0

 signals:
     void update();
 };

 class RenderArea : public QWidget
 {
     Q_OBJECT

 public:
     explicit RenderArea(QWidget *parent = nullptr);

     void setLevel(qreal value);

 protected:
     void paintEvent(QPaintEvent *event) override;

 private:
     qreal m_level = 0;
     QPixmap m_pixmap;
 };

 class InputTest : public QMainWindow
 {
     Q_OBJECT

 public:
     InputTest();

 private:
     void initializeWindow();
     void initializeAudio(const QAudioDeviceInfo &deviceInfo);

 private slots:
     void toggleMode();
     void toggleSuspend();
     void deviceChanged(int index);
     void sliderChanged(int value);

 private:
     // Owned by layout
     RenderArea *m_canvas = nullptr;
     QPushButton *m_modeButton = nullptr;
     QPushButton *m_suspendResumeButton = nullptr;
     QComboBox *m_deviceBox = nullptr;
     QSlider *m_volumeSlider = nullptr;

     QScopedPointer<AudioInfo> m_audioInfo;
     QScopedPointer<QAudioInput> m_audioInput;
     bool m_pullMode = true;
 };

 #endif // AUDIOINPUT_H