How to play a fixed tone sequence

A fixed tone sequence is one that is predefined in DevSound and referenced by a number. To play a fixed tone sequence do the following:

• Constructing and initializing

• Configuring

• Playing

Use the CMMFDevSound::NewL() method to construct a new instance of DevSound.

After construction, use an CMMFDevSound::InitializeL() method to initialize DevSound to play tones. This method requires that you specify the DevSound observer class to handle callbacks.

Once initialization has completed, successfully or otherwise, DevSound calls the MDevSoundObserver::InitializeComplete() function.

The following settings can be configured before or during tone play:

• To return the number of available predefined tone sequences, use the CMMFDevSound::FixedSequenceCount() method:

  IMPORT_C TInt FixedSequenceCount();

  This is the number of fixed sequences supported by DevSound by default.

• To return the name assigned to a specific predefined tone sequence, use the CMMFDevSound::FixedSequenceName() method:

  IMPORT_C const TDesC &FixedSequenceName(TInt aSequenceNumber);

  This method has one parameter, aSequenceNumber, the index identifying the specific predefined tone sequence and returns a reference to a descriptor containing the fixed sequence name indexed by aSequenceNumber.

• To change the volume of the audio device to a specific value, use the CMMFDevSound::SetVolume() function. The volume can be set to any value from 0 to CMMFDevSound::MaxVolume().

  To define a period over which the volume rises from 0 to the normal volume level, use the CMMFDevSound::SetVolumeRamp() function.

  Note: The CMMFDevSound::SetVolumeRamp() function is only available during tone play.

• To set the speaker balance, use the CMMFDevSound::SetPlayBalanceL() function. This function has two parameters:

  • aLeftPercentage - the left speaker volume percentage.

  • aRightPercentage - the right speaker volume percentage.

• To set the priority setting for this instance of DevSound to access the audio device, use the CMMFDevSound::SetPrioritySettings() method. Priority settings are used by the Audio Policy component to resolve multiple requests to access the audio hardware.

To start playing a fixed tone sequence, use the CMMFDevSound::PlayFixedSequenceL() method:

IMPORT_C void PlayFixedSequenceL(TInt aSequenceNumber);

This method has one parameter, aSequenceNumber, the index identifying the specific predefined tone sequence to be played.

When an attempt to play a fixed tone sequence has completed, successfully or otherwise, DevSound calls the MDevSoundObserver::ToneFinished() function.

Note: Further calls to CMMFDevSound::PlayFixedSequenceL() can be made both before and after the MDevSoundObserver::ToneFinished() callback is received.