CMmfGlobalAudioEffect Class Reference
| class CMmfGlobalAudioEffect : public CBase |
Parent class for global audio effects All global effect class derive from this class. It should be seen as an abstract class providing common facilities, that they all share. Users of these classes should be aware that there could be multiple instances, at any one go - e.g. in separate processes. All instances should use event notification (see RequestNotificationL()) to observe changes in values, in case another instance has changed things. If there is more than one output device on a phone, then the behaviour is system dependent, but typical behaviour would be for the settings etc only to apply to the current device - switching output device would lead to a direct change in the settings reported.
Constructor & Destructor Documentation
CMmfGlobalAudioEffect()
| IMPORT_C | CMmfGlobalAudioEffect | ( | ) | [protected] |
~CMmfGlobalAudioEffect()
| IMPORT_C | ~CMmfGlobalAudioEffect | ( | ) | |
Member Functions Documentation
BaseConstructL(TUid, MMmfGlobalAudioEffectObserver *)
Should be called in the ConstructL() of any derived type
- leave
- KErrNotSupported Cannot find implementation for given derived class
Parameters
| TUid aImplementationUid | Fixed for a given derived class, it is used to find the correct plugin or similar that implements that class. |
| MMmfGlobalAudioEffectObserver * aObserver | Observer class. Could be NULL, in which case RequestNotificationL() would not be supported |
Capability(TBool)
Request capabilities of this object. Return the capabilities of the particular GlobalAudioEffect. If aCurrentOnly is false, then it will return all the possible features of the implementation, whereas if it is true only the features available at that moment are indicated. For example, an implementation may support returning the value by UID, but if it was set by UID. In such a circumstance, the bit will always be true if aCurrentOnly is false, but if aCurrentOnly is true and the value had been (say) set by descriptor, then that bit will be false.
Parameters
| TBool aCurrentOnly | If true, capabilities are for current situation only - see text |
CreateCustomInterface(TUid)
| IMPORT_C TInt | CreateCustomInterface | ( | TUid | aInterfaceUid | ) | [protected] |
Request extension feature. This is intended to provide additional features, should a particular global effect need it. In typical use, the global effect will make a call to this interface on construction. Repeatedly calling this interface will have no additional effect - if the interface has already been setup internally, then no further activity will take place.
Parameters
| TUid aInterfaceUid | Used to indicate which interface is required. |
CustomInterface(TUid)
| IMPORT_C TAny * | CustomInterface | ( | TUid | aInterfaceUid | ) | [protected] |
Return previously created extension. This returns a custom interface, used to provide additional features for a certain global effect. This should only be used if CreateCustomInterface() has already been called for the same UID value. This means that any construction for that interface has already been called, and thus this call cannot fail. Typically the returned class will be another Mixin.No transfer of ownership is implied.
CreateCustomInterface()
Parameters
| TUid aInterfaceUid | Used to indicate which interface is required. |
ExtractValuesL(TDes8 &)
| IMPORT_C void | ExtractValuesL | ( | TDes8 & | aPackageBuf | ) | |
Extract the settings into a struct This extracts the current settings, and other data such as min/max values supported. This is intended to support direct selecting of values via graphical controls. Unlike
SettingsByDesL(), the parameter is expected to be a package buffer wrapping a known class/struct, which will be defined by the particular derivation of this class.
- leave
- KErrNotSupported This will only be supported by some child classes, and even then will not be supported by all implementations.
Parameters
| TDes8 & aPackageBuf | This should be a package buffer wrapping the appropriate class/struct, and will be specific to a particular CMmfGlobalAudioEffect derivitive. |
IsActive()
| IMPORT_C TBool | IsActive | ( | ) | const |
The particular effect is active Active is defined as being that the effect is in use - that is audio data is being played through it
IsEnabled()
| IMPORT_C TBool | IsEnabled | ( | ) | const |
KnownPresetsL()
Return info about known presets by Uid This is used in connection with
SetSettingsByUidL(). It allows the user to select a preset by name but this to be fed back as a Uid. It should also allow a Uid to be translated back to a name, if required. Ownership of the list itself remains within the effect implementation. The list may be changed on each call to
KnownPresetsL() - users should be careful about caching the returned pointer.
SetSettingsByUidL() - leave
- KErrNotSupported This feature may not be supported in some circumstances
RequestNotificationL(TUid)
| IMPORT_C void | RequestNotificationL | ( | TUid | aEventUid | ) | |
Request to be told about particular events occuring This is a generic facility for providing callbacks as particular events occur. All callbacks are sent to the Observer that was passed on object creation, invoking GAEEventNotificationL(). The following Uids are defined:
KUidMmfGlblAudioEnableChanged - Indicates the value of IsEnabled() has changed. KUidMmfGlblAudioActiveChanged - Indicates the value of IsActive() has changed. KUidMmfGlblAudioPresetsChanged - Indicates the list of known presets etc has been modified. KUidMmfGlblAudioValueChanged - Indicates the settings have been changed
With all these settings, the value of aParam returned to GAEEventNotificationL() will be empty.
Parameters
| TUid aEventUid | Uid specifying event for which notification is requested |
SetByValuesL(const TDesC8 &)
| IMPORT_C void | SetByValuesL | ( | const TDesC8 & | aPackageBuf | ) | |
Sets current settings from appropriate struct. This takes the same struct as used for
ExtractValuesL() and changes the current settings. Typically it will be used at the end of a dialog to update the data.
- leave
- KErrNotSupported This will only be supported by some child classes, and even then will not be supported by all implementations.
- leave
- KErrArgument Passed package buffer is not the expected size, or individual values are out of range
Parameters
| const TDesC8 & aPackageBuf | This should be a package buffer wrapping the appropriate class/struct, and will be specific to a particular CMmfGlobalAudioEffect derivitive. |
SetEnabledL(TBool)
| IMPORT_C void | SetEnabledL | ( | TBool | aValue | ) | |
Enable (or disable) this effect If not enabled, the Effect will not change the data being passed through. However, the values associated with the effect. Where audio data is being played, the effect will take place immediately.
Parameters
| TBool aValue | If true, enables this specific effect. If false, disables it. |
SetSettingsByDesL(const TDesC8 &)
| IMPORT_C void | SetSettingsByDesL | ( | const TDesC8 & | aParam | ) | |
Change settings by descriptor Update the current settings from values stored in a descriptor. The value in the descriptor will typically have been created using
SettingsByDesL().
- leave
- KErrNotSupported This implementation does not support expressing settings in descriptor form
- leave
- KErrCorrupt Value in descriptor does not correspond to known format
Parameters
| const TDesC8 & aParam | Descriptor value to use |
SetSettingsByUidL(TUid)
| IMPORT_C void | SetSettingsByUidL | ( | TUid | aPresetUid | ) | |
Change settings by passing Uid Change the settings using a uid, that represents a preset. The uid could be known, but should preferably be obtained by using RequestPresets()
- leave
- KErrNotSupported This implementation does not support presets for this effect
- leave
- KErrUnknown The value of aUid does not correspond to a known preset
RequestPresets()
Parameters
| TUid aPresetUid | Uid representing the preset in question |
SettingsByDesL()
| IMPORT_C HBufC8 * | SettingsByDesL | ( | ) | const |
Obtain current settings by descriptor Return an HBufC8* representing the current settings. The format of this descriptor is not specified, but in any given implementation it must be usable by
SetSettingsByDesL(). Ownership of the descriptor is passed back to the calling code.
- leave
- KErrNotSupported This implementation does not support expressing settings in descriptor form
SetSettingsByDesL()
SettingsByUidL()
| IMPORT_C TUid | SettingsByUidL | ( | ) | const |
Obtain uid-based current settings If the value was set using
SetSettingsByUidL() then this returns that setting. Note: can use Capability(ETrue) to avoid unnecessarily leave.
- leave
- KErrNotSupported The settings cannot be expressed as a Uid (usually means SetSettingsByUidL() was not the last thing to change them).
Member Enumerations Documentation
Enum TCapabilityFlags
Flags denoting capability of specific global effect. These flags allow the client app to equire about the capabilities of the given effect. It should be noted that these refer to the specific implementation, and not necessarily the effect class
Enumerators
| ECapabilitySupportsInvidividualValues = 0x0001 | |
| ECapabilitySupportsSettingByUid = 0x0002 | |
| ECapabilitySupportsSetSettingByUid = 0x0004 | |
| ECapabilitySupportsSettingByDes = 0x0008 | |
| ECapabilitySupportsSetSettingByDes = 0x0010 | |
| ECapabilitySupportsActiveChangedCallback = 0x0020 | |
| ECapabilitySupportsEnableChangedCallback = 0x0040 | |
| ECapabilitySupportsPresetChangedCallback = 0x0080 | |
Enum TVolumeValue
Indication of how to interpret volume settings.
Enumerators
| EVolValueAbsolute | |
| EVolValuedB | |
Member Data Documentation
MMmfGlobalAudioImpl * iBaseImplementation
Copyright ©2010 Nokia Corporation and/or its subsidiary(-ies).
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reserved. Unless otherwise stated, these materials are provided under the terms of the Eclipse Public License
v1.0.