org.havi.ui

Interface HNavigable

All Superinterfaces:

HNavigationInputPreferred

All Known Subinterfaces:

HActionable, HAdjustmentValue, HItemValue, HSwitchable, HTextValue

All Known Implementing Classes:

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

public interface HNavigable
extends HNavigationInputPreferred

This interface is implemented by all HAVi UI components that can be navigated to by the user (i.e. components which can gain focus).

Event Behavior

Subclasses of HComponent which implement HNavigable must respond to HFocusEvent events.

Applications should assume that classes which implement HNavigable can generate events of the type HFocusEvent in response to other types of input event.

An application may add one or more HFocusListener listeners to the component. The focusGained and focusLost methods of the HFocusListener are invoked whenever the HNavigable gains or loses focus.

An HNavigable has an arbitrary focus traversal table associated with it (see setMove and getMove). This mechanism allows the four-way focus behavior of a set of components to be set (see setFocusTraversal, setMove and getMove).

HAVi focus events are discussed in detail in the HNavigationInputPreferred interface description.

Interaction States

The following interaction states are valid for this HNavigable component:

• NORMAL_STATE
• FOCUSED_STATE
• DISABLED_STATE
• DISABLED_FOCUSED_STATE

The state machine diagram below shows the valid state transitions for an HNavigable component.

Platform Classes

The following HAVi platform classes implement or inherit the HNavigable interface. These classes shall all generate HFocusEvent events in addition to any other events specified in the respective class descriptions.

• HAnimation
• HIcon
• HText
• HRange
• HGraphicButton
• HTextButton
• HToggleButton
• HListGroup
• HSinglelineEntry
• HMultilineEntry
• HRangeValue

See Also:

HNavigationInputPreferred, HFocusEvent, HFocusListener

Method Summary

Methods

Modifier and Type	Method and Description
void	addHFocusListener(HFocusListener l) Adds the specified HFocusListener to receive HFocusEvent events sent from this HNavigable: If the listener has already been added further calls will add further references to the listener, which will then receive multiple copies of a single event.
HSound	getGainFocusSound() Get the sound associated with the gain focus event.
HSound	getLoseFocusSound() Get the sound associated with the lost focus event.
HNavigable	getMove(int keyCode) Provides the HNavigable object that is navigated to when a particular key is pressed.
boolean	isSelected() Indicates if this component has focus.
void	removeHFocusListener(HFocusListener l) Removes the specified HFocusListener so that it no longer receives HFocusEvent events from this HNavigable.
void	setFocusTraversal(HNavigable up, HNavigable down, HNavigable left, HNavigable right) Set the focus control for an HNavigable component.
void	setGainFocusSound(HSound sound) Associate a sound with gaining focus, i.e.
void	setLoseFocusSound(HSound sound) Associate a sound with losing focus, i.e.
void	setMove(int keyCode, HNavigable target) Defines the navigation path from the current HNavigable to another HNavigable when a particular key is pressed.

Methods inherited from interface org.havi.ui.HNavigationInputPreferred

getNavigationKeys, processHFocusEvent

Method Detail

setMove

void setMove(int keyCode,
           HNavigable target)

Defines the navigation path from the current HNavigable to another HNavigable when a particular key is pressed.

Note that setFocusTraversal is equivalent to multiple calls to setMove, where the key codes VK_UP, VK_DOWN, VK_LEFT, VK_RIGHT are used.

Parameters:

keyCode - The key code of the pressed key. Any numerical keycode is allowed, but the platform may not be able to generate all keycodes. Application authors should only use keys for which HRcCapabilities.isSupported() or HKeyCapabilities.isSupported() returns true.

target - The target HNavigable object that should be navigated to. If a target is to be removed from a particular navigation path, then null shall be specified.

getMove

HNavigable getMove(int keyCode)

Provides the HNavigable object that is navigated to when a particular key is pressed.

Parameters:

keyCode - The key code of the pressed key.

Returns:

Returns the HNavigable object or null if no HNavigable is associated with the keyCode.

setFocusTraversal

void setFocusTraversal(HNavigable up,
                     HNavigable down,
                     HNavigable left,
                     HNavigable right)

Set the focus control for an HNavigable component. Note setFocusTraversal is a convenience function for application programmers where a standard up, down, left and right focus traversal between components is required.

Note setFocusTraversal is equivalent to multiple calls to setMove, where the key codes VK_UP, VK_DOWN, VK_LEFT, VK_RIGHT are used.

Note that this API does not prevent the creation of "isolated" HNavigable components --- authors should endeavor to avoid confusing the user.

Parameters:

up - The HNavigable component to move to, when the user generates a VK_UP KeyEvent. If there is no HNavigable component to move "up" to, then null shall be specified.

down - The HNavigable component to move to, when the user generates a VK_DOWN KeyEvent. If there is no HNavigable component to move "down" to, then null shall be specified.

left - The HNavigable component to move to, when the user generates a VK_LEFT KeyEvent. If there is no HNavigable component to move "left" to, then null shall be specified.

right - The HNavigable component to move to, when the user generates a VK_RIGHT KeyEvent. If there is no HNavigable component to move "right" to, then null shall be specified.

isSelected

boolean isSelected()

Indicates if this component has focus.

Returns:

true if the component has focus, otherwise returns false.

setGainFocusSound

void setGainFocusSound(HSound sound)

Associate a sound with gaining focus, i.e. when the HNavigable receives a HFocusEvent event of type FOCUS_GAINED. This sound will start to be played when an object implementing this interface gains focus. It is not guaranteed to be played to completion. If the object implementing this interface loses focus before the audio completes playing, the audio will be truncated. Applications wishing to ensure the audio is always played to completion must implement special logic to slow down the focus transitions.

By default, an HNavigable object does not have any gain focus sound associated with it.

Note that the ordering of playing sounds is dependent on the order of the focus lost, gained events.

Parameters:

sound - the sound to be played, when the component gains focus. If sound content is already set, the original content is replaced. To remove the sound specify a null HSound.

setLoseFocusSound

void setLoseFocusSound(HSound sound)

Associate a sound with losing focus, i.e. when the HNavigable receives a HFocusEvent event of type FOCUS_LOST. This sound will start to be played when an object implementing this interface loses focus. It is not guaranteed to be played to completion. It is implementation dependent whether and when this sound will be truncated by any gain focus sound played by the next object to gain focus.

By default, an HNavigable object does not have any lose focus sound associated with it.

Note that the ordering of playing sounds is dependent on the order of the focus lost, gained events.

Parameters:

sound - the sound to be played, when the component loses focus. If sound content is already set, the original content is replaced. To remove the sound specify a null HSound.

getGainFocusSound

HSound getGainFocusSound()

Get the sound associated with the gain focus event.

Returns:

The sound played when the component gains focus. If no sound is associated with gaining focus, then null shall be returned.

getLoseFocusSound

HSound getLoseFocusSound()

Get the sound associated with the lost focus event.

Returns:

The sound played when the component loses focus. If no sound is associated with losing focus, then null shall be returned.

addHFocusListener

void addHFocusListener(HFocusListener l)

Adds the specified HFocusListener to receive HFocusEvent events sent from this HNavigable: If the listener has already been added further calls will add further references to the listener, which will then receive multiple copies of a single event.

Parameters:

l - the HFocusListener to add

removeHFocusListener

void removeHFocusListener(HFocusListener l)

Removes the specified HFocusListener so that it no longer receives HFocusEvent events from this HNavigable. If the specified listener is not registered, the method has no effect. If multiple references to a single listener have been registered it should be noted that this method will only remove one reference per call.

Parameters:

l - the HFocusListener to remove