Qt 5.11 | Qt Multimedia | C++ Classes | QRadioTuner

Qt 5.11.3 Reference Documentation

# QRadioTuner Class

The QRadioTuner class provides an interface to the systems analog radio device. More...

Header: | #include <QRadioTuner>
qmake: | QT += multimedia
Inherits: | QMediaObject

- List of all members, including inherited members

## Public Types

enum | Band { AM, FM, SW, LW, FM2 }
enum | Error { NoError, ResourceError, OpenError, OutOfRangeError }
enum | SearchMode { SearchFast, SearchGetStationId }
enum | State { ActiveState, StoppedState }
enum | StereoMode { ForceStereo, ForceMono, Auto }

## Properties

antennaConnected : const bool band : Band frequency : int muted : bool radioData : QRadioData* const searching : const bool | signalStrength : const int state : const State stereo : const bool stereoMode : StereoMode volume : int

- 1 property inherited from QMediaObject

## Public Functions

| QRadioTuner(QObject *parent = nullptr)
virtual | ~QRadioTuner()
QRadioTuner::Band | band() const
QRadioTuner::Error | error() const
QString | errorString() const
int | frequency() const
QPair<int, int> | frequencyRange(QRadioTuner::Band band) const
int | frequencyStep(QRadioTuner::Band band) const
bool | isAntennaConnected() const
bool | isBandSupported(QRadioTuner::Band band) const
bool | isMuted() const
bool | isSearching() const
bool | isStereo() const
QRadioData * | radioData() const
void | setStereoMode(QRadioTuner::StereoMode mode)
int | signalStrength() const
QRadioTuner::State | state() const
QRadioTuner::StereoMode | stereoMode() const
int | volume() const

## Reimplemented Public Functions

virtual QMultimedia::AvailabilityStatus | availability() const override

- 10 public functions inherited from QMediaObject

## Public Slots

void | cancelSearch()
void | searchAllStations(QRadioTuner::SearchMode searchMode = QRadioTuner::SearchFast)
void | searchBackward()
void | searchForward()
void | setBand(QRadioTuner::Band band)
void | setFrequency(int frequency)
void | setMuted(bool muted)
void | setVolume(int volume)
void | start()
void | stop()

## Signals

void | antennaConnectedChanged(bool connectionStatus)
void | bandChanged(QRadioTuner::Band band)
void | error(QRadioTuner::Error error)
void | frequencyChanged(int frequency)
void | mutedChanged(bool muted)
void | searchingChanged(bool searching)
void | signalStrengthChanged(int strength)
void | stateChanged(QRadioTuner::State state)
void | stationFound(int frequency, QString stationId)
void | stereoStatusChanged(bool stereo)
void | volumeChanged(int volume)

- 6 signals inherited from QMediaObject

### Additional Inherited Members

- 2 protected functions inherited from QMediaObject

## Detailed Description

The QRadioTuner class provides an interface to the systems analog radio device.

You can control the systems analog radio device using this interface, for example:

      radio = new QRadioTuner;
      connect(radio, SIGNAL(frequencyChanged(int)), this, SLOT(freqChanged(int)));
      if (radio->isBandSupported(QRadioTuner::FM)) {
          radio->setBand(QRadioTuner::FM);
          radio->setFrequency(yourRadioStationFrequency);
          radio->setVolume(100);
          radio->start();
      }

The radio object will emit signals for any changes in state such as: bandChanged(), frequencyChanged(), stereoStatusChanged(), searchingChanged(), signalStrengthChanged(), volumeChanged(), mutedChanged().

You can change between the frequency bands using setBand() however it is recommended that you check to make sure the band is available first using isBandSupported().

See also QRadioData and Radio Overview.

## Member Type Documentation

### enum QRadioTuner::Band

Enumerates radio frequency bands.

Constant | Value | Description
--- | --- | ---
`QRadioTuner::AM` | `0` | 520 to 1610 kHz, 9 or 10kHz channel spacing, extended 1610 to 1710 kHz
`QRadioTuner::FM` | `1` | 87.5 to 108.0 MHz, except Japan 76-90 MHz
`QRadioTuner::SW` | `2` | 1.711 to 30.0 MHz, divided into 15 bands. 5kHz channel spacing
`QRadioTuner::LW` | `3` | 148.5 to 283.5 kHz, 9kHz channel spacing (Europe, Africa, Asia)
`QRadioTuner::FM2` | `4` | range not defined, used when area supports more than one FM range.

### enum QRadioTuner::Error

Enumerates radio tuner error conditions.

Constant | Value | Description
--- | --- | ---
`QRadioTuner::NoError` | `0` | No errors have occurred.
`QRadioTuner::ResourceError` | `1` | There is no radio service available.
`QRadioTuner::OpenError` | `2` | Unable to open radio device.
`QRadioTuner::OutOfRangeError` | `3` | An attempt to set a frequency or band that is not supported by radio device.

### enum QRadioTuner::SearchMode

Enumerates how the radio tuner should search for stations.

Constant | Value | Description
--- | --- | ---
`QRadioTuner::SearchFast` | `0` | Use only signal strength when searching.
`QRadioTuner::SearchGetStationId` | `1` | After finding a strong signal, wait for the RDS station id (PI) before continuing.

### enum QRadioTuner::State

Enumerates radio tuner states.

Constant | Value | Description
--- | --- | ---
`QRadioTuner::ActiveState` | `0` | The tuner is started and active.
`QRadioTuner::StoppedState` | `1` | The tuner device is stopped.

### enum QRadioTuner::StereoMode

Enumerates radio tuner policy for receiving stereo signals.

Constant | Value | Description
--- | --- | ---
`QRadioTuner::ForceStereo` | `0` | Provide stereo mode, converting if required.
`QRadioTuner::ForceMono` | `1` | Provide mono mode, converting if required.
`QRadioTuner::Auto` | `2` | Uses the stereo mode matching the station.

## Property Documentation

### antennaConnected : const bool

This property holds whether there is an antenna connected

Access functions:

bool | isAntennaConnected() const

Notifier signal:

void | antennaConnectedChanged(bool connectionStatus)

### band : Band

This property holds the frequency band a radio tuner is tuned to.

Access functions:

QRadioTuner::Band | band() const
void | setBand(QRadioTuner::Band band)

Notifier signal:

void | bandChanged(QRadioTuner::Band band)

See also QRadioTuner::Band.

### frequency : int

This property holds the frequency in Hertz a radio tuner is tuned to.

Access functions:

int | frequency() const
void | setFrequency(int frequency)

Notifier signal:

void | frequencyChanged(int frequency)

### muted : bool

This property holds whether a radio tuner's audio output is muted.

Access functions:

bool | isMuted() const
void | setMuted(bool muted)

Notifier signal:

void | mutedChanged(bool muted)

### radioData : QRadioData* const

holds an instance of QRadioData

The instance of QRadioData is already bound to this instance of QRadioTuner.

Access functions:

QRadioData * | radioData() const

### searching : const bool

This property holds whether a radio tuner is currently scanning for a signal.

Access functions:

bool | isSearching() const

Notifier signal:

void | searchingChanged(bool searching)

See also searchForward(), searchBackward(), and cancelSearch().

### signalStrength : const int

This property holds the strength of the current radio signal as a percentage.

Access functions:

int | signalStrength() const

Notifier signal:

void | signalStrengthChanged(int strength)

### state : const State

Return the current radio tuner state.

Access functions:

QRadioTuner::State | state() const

Notifier signal:

void | stateChanged(QRadioTuner::State state)

See also QRadioTuner::State.

### stereo : const bool

This property holds whether a radio tuner is receiving a stereo signal.

Access functions:

bool | isStereo() const

Notifier signal:

void | stereoStatusChanged(bool stereo)

### stereoMode : StereoMode

This property holds the stereo mode of a radio tuner.

Access functions:

QRadioTuner::StereoMode | stereoMode() const
void | setStereoMode(QRadioTuner::StereoMode mode)

### volume : int

This property holds the volume of a radio tuner's audio output as a percentage.

Access functions:

int | volume() const
void | setVolume(int volume)

Notifier signal:

void | volumeChanged(int volume)

## Member Function Documentation

### QRadioTuner::QRadioTuner(QObject *parent = nullptr)

Constructs a radio tuner based on a media service allocated by the default media service provider.

The parent is passed to QMediaObject.

### `[virtual]` QRadioTuner::~QRadioTuner()

Destroys a radio tuner.

### `[override virtual]` QMultimedia::AvailabilityStatus QRadioTuner::availability() const

Reimplemented from QMediaObject::availability().

Returns the availability of the radio tuner.

### `[signal]` void QRadioTuner::bandChanged(QRadioTuner::Band band)

Signals a radio tuner's band has changed.

Note: Notifier signal for property band.

### `[slot]` void QRadioTuner::cancelSearch()

Stops scanning for a signal.

See also searchForward(), searchBackward(), and searching.

### QRadioTuner::Error QRadioTuner::error() const

Returns the error state of a radio tuner.

See also errorString().

### `[signal]` void QRadioTuner::error(QRadioTuner::Error error)

Signals that an error occurred.

Note: Signal error is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:

      connect(radioTuner, QOverload<QRadioTuner::Error>::of(&QRadioTuner::error),
          [=](QRadioTuner::Error error){ /* ... */ });

### QString QRadioTuner::errorString() const

Returns a description of a radio tuner's error state.

See also error().

### `[signal]` void QRadioTuner::frequencyChanged(int frequency)

Signals that the frequency a radio tuner is tuned to has changed.

Note: Notifier signal for property frequency.

### QPair<int, int> QRadioTuner::frequencyRange(QRadioTuner::Band band) const

Returns a frequency band's minimum and maximum frequency.

### int QRadioTuner::frequencyStep(QRadioTuner::Band band) const

Returns the number of Hertz to increment the frequency by when stepping through frequencies within a given band.

### bool QRadioTuner::isBandSupported(QRadioTuner::Band band) const

Identifies if a frequency band is supported by a radio tuner.

Returns true if the band is supported, and false if it is not.

### `[signal]` void QRadioTuner::mutedChanged(bool muted)

Signals that the muted state of a radio tuner's audio output has changed.

Note: Notifier signal for property muted.

### `[slot]` void QRadioTuner::searchAllStations(QRadioTuner::SearchMode searchMode = QRadioTuner::SearchFast)

Search all stations in current band

Emits QRadioTuner::stationFound(int, QString) for every found station. After searching is completed, QRadioTuner::searchingChanged(bool) is emitted (false). If searchMode is set to SearchGetStationId, searching waits for station id (PI) on each frequency.

See also searchForward(), searchBackward(), and searching.

### `[slot]` void QRadioTuner::searchBackward()

Starts a backwards scan for a signal, starting from the current frequency.

See also searchForward(), cancelSearch(), and searching.

### `[slot]` void QRadioTuner::searchForward()

Starts a forward scan for a signal, starting from the current frequency.

See also searchBackward(), cancelSearch(), and searching.

### `[signal]` void QRadioTuner::searchingChanged(bool searching)

Signals that the searching state of a radio tuner has changed.

Note: Notifier signal for property searching.

### `[slot]` void QRadioTuner::setBand(QRadioTuner::Band band)

Sets a radio tuner's frequency band.

Changing the band will reset the frequency to the new band's minimum frequency.

Note: Setter function for property band.

See also band().

### `[slot]` void QRadioTuner::setFrequency(int frequency)

Sets a radio tuner's frequency.

If the tuner is set to a frequency outside the current band, the band will be changed to one occupied by the new frequency.

Note: Setter function for property frequency.

See also frequency().

### `[signal]` void QRadioTuner::signalStrengthChanged(int strength)

Signals that the strength of the signal received by a radio tuner has changed.

Note: Notifier signal for property signalStrength.

### `[slot]` void QRadioTuner::start()

Activate the radio device.

### `[signal]` void QRadioTuner::stateChanged(QRadioTuner::State state)

This signal is emitted when the state changes to state.

Note: Notifier signal for property state.

### `[signal]` void QRadioTuner::stationFound(int frequency, QString stationId)

Signals that a station was found in frequency with stationId Program Identification code.

### `[signal]` void QRadioTuner::stereoStatusChanged(bool stereo)

Signals that the stereo state of a radio tuner has changed.

Note: Notifier signal for property stereo.

### `[slot]` void QRadioTuner::stop()

Deactivate the radio device.

### `[signal]` void QRadioTuner::volumeChanged(int volume)

Signals that the volume of a radio tuner's audio output has changed.

Note: Notifier signal for property volume.