Tactile +feedback client API

The Tactile feedback client API is a library API that has been implemented +with a client-server technique. A major part of the processing is done on +the client side, and thus API calls don't necessarily generate a client-server +transaction immediately. Instead for e.g. changes to area registry are buffered, +and then transferred to server-side at once.

The concept of logical feedback type is very important from this API's +point of view.

In practice it means that, for example, you should not try to use this +API for producing vibrator feedback only. Instead, logical feedback types +such as "basic" or "sensitive" are used on this level, and the actual physical +effect then depends on the settings and device configuration. This way the +feedback works in a unified way from the end user point of view in the whole +device.

For user experience guidelines on tactile feedback, see Tactile feedback.

For +information on using the API, see Providing +tactile feedback for touch events.

For the Tactile feedback client +API classes and header files, see Classes +and Definitions.

Error handling

The leave mechanism of Symbian environment is used to handle memory exhaustion. The panic mechanism is not +used.

The table below presents possible error conditions and responses +to them.

Possible +error situations when using Tactile Feedback Client API + + + +Error situation +Response + + + + +SetFeedbackArea returns KErrNoMemory in +case of an OOM situation. +This error can usually be ignored by the application. + + +SetFeedbackArea returns KErrArgument +The given CCoeControl pointer is a NULL pointer +or the control does not have any window associated with it (i.e., the feedback +area setting is attempted before SetContainerWindow has been +called on the control). + + +SetFeedbackArea returns KErrNotSupported. +The given logical feedback type or triggering event type is out of +range. + + +A tactile feedback enabled control is moved with CCoeControl::SetPosition, +but the feedback area is not moved. +The control must override the CCoeControl::PositionChanged function, +and update the feedback area there the same way as in the SizeChanged function. + + +Area registry updates not are effective fast enough. This might happen +in some applications which use very many frequently running active objects, +so that the CIdle object used by the implementation of this +API gets no change to run. +Use the FlushRegistryUpdates function for forcing +an update to the server side after doing all updates on the client side. + + +A control's feedback areas are not automatically disabled when the +control is dimmed. +CCoeControl::SetMopParent has not been called on the +control, and thus the object provider hierarchy is broken. + + + +