org.havi.ui

Interface HNavigationInputPreferred

All Known Subinterfaces:

HActionable, HAdjustmentValue, HItemValue, HNavigable, HSwitchable, HTextValue

All Known Implementing Classes:

HAnimation, HGraphicButton, HIcon, HListGroup, HMultilineEntry, HRange, HRangeValue, HSinglelineEntry, HText, HTextButton, HTMLInnerApplicationContainer, HToggleButton, InnerApplicationContainer

public interface HNavigationInputPreferred

A component which implements HNavigationInputPreferred indicates that this component expects to receive HFocusEvent events. The focus event system in HAVi is designed to be compatible with standard AWT focus mechanisms while supporting key event-based focus traversal for HAVi UI components.

All interoperable implementations of the HNavigationInputPreferred interface must extend HComponent.

Components which implement HNavigationInputPreferred to handle HFocusEvent events can optionally manage focus traversal based on keyboard input events, in addition to the normal semantics of the FocusEvent.FOCUS_GAINED and FocusEvent.FOCUS_LOST event types. The focus traversal mechanism specified by the HAVI UI HNavigable interface is one such system.

In the case where such an implementation requires specific keys to manage focus traversal the getNavigationKeys() method is provided to allow the HAVi platform to query the set of keys for which a navigation target has been set. When such a component has the input focus, platforms without a physical means of generating the desired keystrokes shall provide another means for navigation e.g. by offering an on-screen "virtual" keyboard. Applications can query the system about the support of specific keyCodes through the HKeyCapabilities.isSupported(int) method.

The keyCodes for navigation keystrokes generated on the HNavigationInputPreferred will be passed to the HNavigationInputPreferred as an HFocusEvent transferId through the processHFocusEvent(org.havi.ui.event.HFocusEvent) method. No HKeyEvent will be generated on the HNavigationInputPreferred as a result of these keystrokes.

Note that the java.awt.Component method isFocusTraversable should always return true for a java.awt.Component implementing this interface.

Method Summary

Methods

Modifier and Type	Method and Description
int[]	getNavigationKeys() Retrieve the set of key codes which this component maps to navigation targets.
void	processHFocusEvent(HFocusEvent evt) Process an HFocusEvent sent to this HNavigationInputPreferred.

Method Detail

getNavigationKeys

int[] getNavigationKeys()

Retrieve the set of key codes which this component maps to navigation targets.

Returns:

an array of key codes, or null if no navigation targets are set on this component.

processHFocusEvent

void processHFocusEvent(HFocusEvent evt)

Process an HFocusEvent sent to this HNavigationInputPreferred.

Parameters:

evt - the HFocusEvent to process.