@stable

@hbcore

\brief The HbVirtualKeyboard class is an abstract base class for virtual keyboards.

This class is an abstract base class for virtual keyboards. It is not responsible

for the visual appearance of the keyboard, but contains methods that the HbVkbHost

class needs when interacting with the keyboard. The concrete widget inheriting

from this class will fill and define the layout for the keyboard contents.

The virtual keyboard host calls aboutToOpen() when it is about to open the keyboard

and keyboardClosed() when the open and close operations have been completed.

after each frame so that that the keyboard widget has the possibility of running

local animation effects inside the widget if needed.

See \ref vkbHandling "virtual keyboard handling guide" for more information

/*!

\enum HbVirtualKeyboard::HbVkbAnimationType

Specifies known virtual keyboard animation types.

*/

/*!

\var HbVirtualKeyboard::HbVkbAnimOpen

Animation type for virtual keyboard opening.

*/

/*!

\var HbVirtualKeyboard::HbVkbAnimClose

Animation type for virtual keyboard closing.

*/

HbVkbHost calls this function right before the keyboard becomes visible.

The virtual keyboard widget can then do any last minute initializations

if needed.

HbVkbHost calls this function right before keyboard is closed.

The virtual keyboard widget can then do any cleaning operations it needs to do.

HbVkbHost calls this function when the keyboard opening operation is finished

and the keyboard is visible on the screen in its final position.

HbVkbHost calls this function when the keyboard closing operation is finished

and the keyboard is no longer visible on the screen.

\fn QSizeF HbVirtualKeyboard::preferredKeyboardSize()

Returns the size of the preferred keyboard.

*/

/*!

\fn void HbVirtualKeyboard::keyboardAnimationFrame(HbVkbAnimationType type, qreal x)

HbVkbHost calls this function when the keyboard animation frame is drawn.

The keyboard widget may then animate its contents if needed. Parameter \a type

specifies the animation type and value \a x is the animation phase (between 0.0 and 1.0).

\fn HbKeyboardType HbVirtualKeyboard::keyboardType() const

Returns the keyboard type. See file \c hbinputdef.h for the possible HbKeyboardType values. 

The default implementation returns HbKeyboardNone.

\fn QWidget * HbVirtualKeyboard::asWidget()

Returns a QWidget pointer to the virtual keyboard widget.

*/

/*!

\fn QGraphicsWidget * HbVirtualKeyboard::asGraphicsWidget()

Returns a QGraphicsWidget pointer to the virtual keyboard widget.