net.rim.device.api.ui.component
Class NullField

java.lang.Object
  net.rim.device.api.ui.Field
      net.rim.device.api.ui.component.NullField

public class NullField
extends Field

A field of no size.

Behaviour
This class provides a field of zero size, which you might find useful for implementing non-standard focus changing. Add a focus change listener to the field and move focus appropriately when it is triggered.

Field Summary

Fields inherited from class net.rim.device.api.ui.Field

ACTION_INVOKE, AXIS_HORIZONTAL, AXIS_SEQUENTIAL, AXIS_VERTICAL, EDITABLE, EDITABLE_MASK, FIELD_BOTTOM, FIELD_HALIGN_MASK, FIELD_HCENTER, FIELD_LEADING, FIELD_LEFT, FIELD_RIGHT, FIELD_TOP, FIELD_TRAILING, FIELD_VALIGN_MASK, FIELD_VCENTER, FOCUSABLE, FOCUSABLE_MASK, HIGHLIGHT_FOCUS, HIGHLIGHT_SELECT, NON_FOCUSABLE, NON_SPELLCHECKABLE, READONLY, SPELLCHECKABLE, SPELLCHECKABLE_MASK, STATUS_MOVE_FOCUS_HORIZONTALLY, STATUS_MOVE_FOCUS_VERTICALLY, USE_ALL_HEIGHT, USE_ALL_WIDTH, VISUAL_STATE_ACTIVE, VISUAL_STATE_DISABLED, VISUAL_STATE_DISABLED_FOCUS, VISUAL_STATE_FOCUS, VISUAL_STATE_NORMAL

Constructor Summary

NullField()
Constructs a new NullField object.

NullField(long style)
Constructs a new NullField object with the provided style.

Method Summary
void	getFocusRect(XYRect rect) Retrieves this field's current focus region.
int	getPreferredHeight() Retrieves this field's preferred height.
int	getPreferredWidth() Retrieves this field's preferred width.
protected void	layout(int width, int height) Lays out field contents.
protected void	paint(Graphics graphics) Invoked by the framework to redraw this field.

Methods inherited from class net.rim.device.api.ui.Field

drawFocus, drawHighlightRegion, fieldChangeNotify, focusAdd, focusRemove, getAccessibleContext, getBackground, getBackground, getBorder, getBorder, getBorder, getChangeListener, getCommandItemProvider, getContentHeight, getContentLeft, getContentRect, getContentRect, getContentTop, getContentWidth, getContextMenu, getCookie, getExtent, getExtent, getFieldStyle, getFocusListener, getFont, getHeight, getIndex, getLeafFieldWithFocus, getLeft, getManager, getMargin, getMarginBottom, getMarginLeft, getMarginRight, getMarginTop, getOriginal, getPadding, getPaddingBottom, getPaddingLeft, getPaddingRight, getPaddingTop, getScreen, getStyle, getTop, getVisualState, getWidth, invalidate, invalidate, invalidateAll, invokeAction, isDataValid, isDirty, isEditable, isEnabled, isFocus, isFocusable, isMuddy, isPasteable, isScrollCopyable, isSelectable, isSelecting, isSelectionCopyable, isSelectionCutable, isSelectionDeleteable, isSpellCheckable, isStyle, isVisible, keyChar, keyControl, keyDown, keyRepeat, keyStatus, keyUp, makeContextMenu, moveFocus, moveFocus, navigationClick, navigationMovement, navigationUnclick, onDisplay, onExposed, onFocus, onMenuDismissed, onMenuDismissed, onObscured, onUndisplay, onUnfocus, onVisibilityChange, paste, select, selectionCopy, selectionCut, selectionDelete, setBackground, setBackground, setBorder, setBorder, setBorder, setBorder, setChangeListener, setCommandItemProvider, setCookie, setDirty, setEditable, setEnabled, setExtent, setFocus, setFocusListener, setFont, setMargin, setMargin, setMuddy, setNonSpellCheckable, setPadding, setPadding, setPosition, setVisualState, touchEvent, trackwheelClick, trackwheelUnclick, updateLayout

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NullField

public NullField()

Constructs a new NullField object.

This constructor builds a new null field object with the default (no) style.

NullField

public NullField(long style)

Constructs a new NullField object with the provided style.

Parameters:

style - Style for the new null field.

Method Detail

getPreferredWidth

public int getPreferredWidth()

Retrieves this field's preferred width. See Field.getPreferredWidth() for more information.

Overrides:

getPreferredWidth in class Field

Returns:

Zero (this null field has no width).

getPreferredHeight

public int getPreferredHeight()

Retrieves this field's preferred height. See Field.getPreferredHeight() for more information.

Overrides:

getPreferredHeight in class Field

Returns:

Zero (this null field has no height).

layout

protected void layout(int width,
                      int height)

Lays out field contents.

Invoking this method invokes Field.setExtent(int,int) with zero for both width and height.

Specified by:

layout in class Field

Parameters:

width - Ignored.

height - Ignored.

paint

protected void paint(Graphics graphics)

Invoked by the framework to redraw this field.

This field's manager invokes this method when the field has been marked as invalid. However, since the field has no extent to repaint, this method does nothing.

Specified by:

paint in class Field

Parameters:

graphics - Ignored.

getFocusRect

public void getFocusRect(XYRect rect)

Retrieves this field's current focus region. See Field.getFocusRect(net.rim.device.api.ui.XYRect) for more information.

Overrides:

getFocusRect in class Field

Parameters:

rect - Object to contain the focus rect for this field in local coordinates.

Since:

BlackBerry API 6.0.0