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