javax.swing.plaf.basic

Class BasicComboBoxUI

public class BasicComboBoxUI extends ComboBoxUI

A UI delegate for the {@link JComboBox} component.

Nested Class Summary
class	BasicComboBoxUI.ComboBoxLayoutManager A {@link LayoutManager} used to position the sub-components of the {@link JComboBox}.
class	BasicComboBoxUI.FocusHandler Handles focus changes occuring in the combo box.
class	BasicComboBoxUI.ItemHandler Handles {@link ItemEvent}s fired by the {@link JComboBox} when its selected item changes.
class	BasicComboBoxUI.KeyHandler KeyHandler handles key events occuring while JComboBox has focus.
class	BasicComboBoxUI.ListDataHandler Handles the changes occurring in the JComboBox's data model.
class	BasicComboBoxUI.PropertyChangeHandler Handles {@link PropertyChangeEvent}s fired by the {@link JComboBox}.

Field Summary
protected JButton	arrowButton The arrow button that is displayed in the right side of JComboBox.
protected Dimension	cachedMinimumSize The current minimum size if isMinimumSizeDirty is false.
protected JComboBox	comboBox The combo box represented by this UI delegate.
protected CellRendererPane	currentValuePane Used to render the combo box values.
protected Component	editor The component that is responsible for displaying/editing the selected item of the combo box.
protected FocusListener	focusListener A listener listening to focus events occurring in the {@link JComboBox}.
protected boolean	hasFocus A flag indicating whether JComboBox currently has the focus.
protected boolean	isMinimumSizeDirty Indicates whether or not the cachedMinimumSize field is valid or not.
protected ItemListener	itemListener A listener listening to item events fired by the {@link JComboBox}.
protected KeyListener	keyListener A listener listening to key events that occur while {@link JComboBox} has the focus.
protected JList	listBox List used when rendering selected item of the combo box.
protected ListDataListener	listDataListener ListDataListener listening to JComboBox model
protected ComboPopup	popup Popup list containing the combo box's menu items.
protected KeyListener	popupKeyListener
protected MouseListener	popupMouseListener
protected MouseMotionListener	popupMouseMotionListener
protected PropertyChangeListener	propertyChangeListener Listener listening to changes in the bound properties of JComboBox

Constructor Summary
	BasicComboBoxUI() Creates a new `BasicComboBoxUI` object.

Method Summary
void	addEditor() Adds the current editor to the combo box.
void	configureArrowButton() Configures the arrow button.
protected void	configureEditor() Configures the editor for this combo box.
protected JButton	createArrowButton() Creates an arrow button for this {@link JComboBox}.
protected ComboBoxEditor	createEditor() Creates the component that will be responsible for displaying/editing the selected item in the combo box.
protected FocusListener	createFocusListener() Creates the {@link FocusListener} that will listen to changes in this JComboBox's focus.
protected ItemListener	createItemListener() Creates an {@link ItemListener} that will listen to the changes in the JComboBox's selection.
protected KeyListener	createKeyListener() Creates a {@link KeyListener} to listen to key events.
protected LayoutManager	createLayoutManager() Creates and returns a layout manager for the combo box.
protected ListDataListener	createListDataListener() Creates a {@link ListDataListener} to listen to the combo box's data model.
protected ComboPopup	createPopup() Creates the popup that will contain list of combo box's items.
protected PropertyChangeListener	createPropertyChangeListener() Creates a {@link PropertyChangeListener} to listen to the changes in the JComboBox's bound properties.
protected ListCellRenderer	createRenderer() Creates a component that will be responsible for rendering the selected component in the combo box.
static ComponentUI	createUI(JComponent c) A factory method to create a UI delegate for the given {@link JComponent}, which should be a {@link JComboBox}.
Accessible	getAccessibleChild(JComponent c, int i) Returns the accessible child with the specified index.
int	getAccessibleChildrenCount(JComponent c) Returns the number of accessible children of the combobox.
protected Dimension	getDefaultSize() Returns the default size for the display area of a combo box that does not contain any elements.
protected Dimension	getDisplaySize() Returns the size of the display area for the combo box.
protected Insets	getInsets() Returns the insets of the current border.
Dimension	getMaximumSize(JComponent c) Returns the maximum size for this {@link JComboBox} for this look and feel.
Dimension	getMinimumSize(JComponent c) Returns the minimum size for this {@link JComboBox} for this look and feel.
Dimension	getPreferredSize(JComponent c) Returns preferred size for the combo box.
protected void	installComponents() Installs the components for this JComboBox.
protected void	installDefaults() Installs the defaults that are defined in the {@link BasicLookAndFeel} for this {@link JComboBox}.
protected void	installKeyboardActions() Installs the keyboard actions for the {@link JComboBox} as specified by the look and feel.
protected void	installListeners() Creates and installs the listeners for this UI.
void	installUI(JComponent c) Installs the UI for the given {@link JComponent}.
boolean	isFocusTraversable(JComboBox c) JComboBox is focus traversable if it is editable and not otherwise.
protected boolean	isNavigationKey(int keyCode) Returns true if the specified key is a navigation key and false otherwise
boolean	isPopupVisible(JComboBox c) Returns `true` if the popup is visible, and `false` otherwise.
void	paint(Graphics g, JComponent c) Paints given menu item using specified graphics context
void	paintCurrentValue(Graphics g, Rectangle bounds, boolean hasFocus) Paints currently selected value in the main part of the combo box (part without popup).
void	paintCurrentValueBackground(Graphics g, Rectangle bounds, boolean hasFocus) Paints the background of part of the combo box, where currently selected value is displayed.
protected Rectangle	rectangleForCurrentValue() Returns the bounds in which comboBox's selected item will be displayed.
void	removeEditor() Removes the current editor from the combo box.
protected void	selectNextPossibleValue() Selects next possible item relative to the current selection to be next selected item in the combo box.
protected void	selectPreviousPossibleValue() Selects previous item relative to current selection to be next selected item.
void	setPopupVisible(JComboBox c, boolean v) Displays/hides the {@link JComboBox}'s list of items on the screen.
protected void	toggleOpenClose() Displays combo box popup if the popup is not currently shown on the screen and hides it if it is currently shown
void	unconfigureArrowButton() Unconfigures the arrow button.
protected void	unconfigureEditor() Unconfigures the editor for this combo box.
protected void	uninstallComponents() Uninstalls components from this {@link JComboBox}.
protected void	uninstallDefaults() Uninstalls the defaults and sets any objects created during install to `null`.
protected void	uninstallKeyboardActions() Uninstalls the keyboard actions for the {@link JComboBox} there were installed by in {@link #installListeners}.
protected void	uninstallListeners() Detaches all the listeners we attached in {@link #installListeners}.
void	uninstallUI(JComponent c) Uninstalls the UI for the given {@link JComponent}.

Field Detail

arrowButton

protected JButton arrowButton

The arrow button that is displayed in the right side of JComboBox. This button is used to hide and show combo box's list of items.

cachedMinimumSize

protected Dimension cachedMinimumSize

The current minimum size if isMinimumSizeDirty is false. Setup by getMinimumSize() and invalidated by the various listeners.

comboBox

protected JComboBox comboBox

The combo box represented by this UI delegate.

currentValuePane

protected CellRendererPane currentValuePane

Used to render the combo box values.

editor

protected Component editor

The component that is responsible for displaying/editing the selected item of the combo box.

focusListener

protected FocusListener focusListener

A listener listening to focus events occurring in the {@link JComboBox}.

hasFocus

protected boolean hasFocus

A flag indicating whether JComboBox currently has the focus.

isMinimumSizeDirty

protected boolean isMinimumSizeDirty

Indicates whether or not the cachedMinimumSize field is valid or not.

itemListener

protected ItemListener itemListener

A listener listening to item events fired by the {@link JComboBox}.

keyListener

protected KeyListener keyListener

A listener listening to key events that occur while {@link JComboBox} has the focus.

listBox

protected JList listBox

List used when rendering selected item of the combo box. The selection and foreground colors for combo box renderer are configured from this list.

listDataListener

protected ListDataListener listDataListener

ListDataListener listening to JComboBox model

popup

protected ComboPopup popup

Popup list containing the combo box's menu items.

popupMouseListener

protected MouseListener popupMouseListener

popupMouseMotionListener

protected MouseMotionListener popupMouseMotionListener

propertyChangeListener

protected PropertyChangeListener propertyChangeListener

Listener listening to changes in the bound properties of JComboBox

Constructor Detail

BasicComboBoxUI

public BasicComboBoxUI()

Creates a new BasicComboBoxUI object.

Method Detail

addEditor

public void addEditor()

Adds the current editor to the combo box.

configureArrowButton

public void configureArrowButton()

Configures the arrow button.

configureEditor

protected void configureEditor()

Configures the editor for this combo box.

createArrowButton

protected JButton createArrowButton()

Creates an arrow button for this {@link JComboBox}. The arrow button is displayed at the right end of the combo box and is used to display/hide the drop down list of items.

Returns: A new button.

createEditor

protected ComboBoxEditor createEditor()

Creates the component that will be responsible for displaying/editing the selected item in the combo box. This editor is used only when combo box is editable.

Returns: A new component that will be responsible for displaying/editing the selected item in the combo box.

createFocusListener

protected FocusListener createFocusListener()

Creates the {@link FocusListener} that will listen to changes in this JComboBox's focus.

Returns: the FocusListener.

createItemListener

protected ItemListener createItemListener()

Creates an {@link ItemListener} that will listen to the changes in the JComboBox's selection.

Returns: The ItemListener

createKeyListener

protected KeyListener createKeyListener()

Creates a {@link KeyListener} to listen to key events.

Returns: KeyListener that listens to key events.

createLayoutManager

protected LayoutManager createLayoutManager()

Creates and returns a layout manager for the combo box. Subclasses can override this method to provide a different layout.

Returns: a layout manager for the combo box.

createListDataListener

protected ListDataListener createListDataListener()

Creates a {@link ListDataListener} to listen to the combo box's data model.

Returns: The new listener.

createPopup

protected ComboPopup createPopup()

Creates the popup that will contain list of combo box's items.

Returns: popup containing list of combo box's items

createPropertyChangeListener

protected PropertyChangeListener createPropertyChangeListener()

Creates a {@link PropertyChangeListener} to listen to the changes in the JComboBox's bound properties.

Returns: The PropertyChangeListener

createRenderer

protected ListCellRenderer createRenderer()

Creates a component that will be responsible for rendering the selected component in the combo box.

Returns: A renderer for the combo box.

createUI

public static ComponentUI createUI(JComponent c)

A factory method to create a UI delegate for the given {@link JComponent}, which should be a {@link JComboBox}.

Parameters: c The {@link JComponent} a UI is being created for.

Returns: A UI delegate for the {@link JComponent}.

getAccessibleChild

public Accessible getAccessibleChild(JComponent c, int i)

Returns the accessible child with the specified index.

Parameters: c the component, this is ignored i the index of the accessible child to return

getAccessibleChildrenCount

public int getAccessibleChildrenCount(JComponent c)

Returns the number of accessible children of the combobox.

Parameters: c the component (combobox) to check, ignored

Returns: the number of accessible children of the combobox

Returns the default size for the display area of a combo box that does not contain any elements. This method returns the width and height of a single space in the current font, plus a margin of 1 pixel.

Returns: The default display size.

getDisplaySize

protected Dimension getDisplaySize()

Returns the size of the display area for the combo box. This size will be the size of the combo box, not including the arrowButton.

Returns: The size of the display area for the combo box.

getInsets

protected Insets getInsets()

Returns the insets of the current border.

Returns: Insets representing space between combo box and its border

getMaximumSize

public Dimension getMaximumSize(JComponent c)

Returns the maximum size for this {@link JComboBox} for this look and feel.

Parameters: c The {@link JComponent} to find the maximum size for

Returns: The maximum size (Dimension(32767, 32767)).

getMinimumSize

public Dimension getMinimumSize(JComponent c)

Returns the minimum size for this {@link JComboBox} for this look and feel. Also makes sure cachedMinimimSize is setup correctly.

Parameters: c The {@link JComponent} to find the minimum size for.

Returns: The dimensions of the minimum size.

getPreferredSize

public Dimension getPreferredSize(JComponent c)

Returns preferred size for the combo box.

Parameters: c comboBox for which to get preferred size

Returns: The preferred size for the given combo box

installComponents

protected void installComponents()

Installs the components for this JComboBox. ArrowButton, main part of combo box (upper part) and popup list of items are created and configured here.

installDefaults

protected void installDefaults()

Installs the defaults that are defined in the {@link BasicLookAndFeel} for this {@link JComboBox}.

installKeyboardActions

protected void installKeyboardActions()

Installs the keyboard actions for the {@link JComboBox} as specified by the look and feel.

installListeners

protected void installListeners()

Creates and installs the listeners for this UI.

installUI

public void installUI(JComponent c)

Installs the UI for the given {@link JComponent}.

Parameters: c the JComponent to install a UI for.

isFocusTraversable

public boolean isFocusTraversable(JComboBox c)

JComboBox is focus traversable if it is editable and not otherwise.

Parameters: c combo box for which to check whether it is focus traversable

Returns: true if focus tranversable and false otherwise

isNavigationKey

protected boolean isNavigationKey(int keyCode)

Returns true if the specified key is a navigation key and false otherwise

Parameters: keyCode a key for which to check whether it is navigation key or not.

Returns: true if the specified key is a navigation key and false otherwis

isPopupVisible

public boolean isPopupVisible(JComboBox c)

Returns true if the popup is visible, and false otherwise.

Parameters: c The JComboBox to check

Returns: true if popup part of the JComboBox is visible and false otherwise.

paint

public void paint(Graphics g, JComponent c)

Paints given menu item using specified graphics context

Parameters: g The graphics context used to paint this combo box c comboBox which needs to be painted.

paintCurrentValue

public void paintCurrentValue(Graphics g, Rectangle bounds, boolean hasFocus)

Paints currently selected value in the main part of the combo box (part without popup).

Parameters: g graphics context bounds Rectangle representing the size of the area in which selected item should be drawn hasFocus true if combo box has focus and false otherwise

paintCurrentValueBackground

public void paintCurrentValueBackground(Graphics g, Rectangle bounds, boolean hasFocus)

Paints the background of part of the combo box, where currently selected value is displayed. If the combo box has focus this method should also paint focus rectangle around the combo box.

Parameters: g graphics context bounds Rectangle representing the size of the largest item in the comboBox hasFocus true if combo box has fox and false otherwise

rectangleForCurrentValue

protected Rectangle rectangleForCurrentValue()

Returns the bounds in which comboBox's selected item will be displayed.

Returns: rectangle bounds in which comboBox's selected Item will be displayed

removeEditor

public void removeEditor()

Removes the current editor from the combo box.

selectNextPossibleValue

protected void selectNextPossibleValue()

Selects next possible item relative to the current selection to be next selected item in the combo box.

selectPreviousPossibleValue

protected void selectPreviousPossibleValue()

Selects previous item relative to current selection to be next selected item.

setPopupVisible

public void setPopupVisible(JComboBox c, boolean v)

Displays/hides the {@link JComboBox}'s list of items on the screen.

Parameters: c The combo box, for which list of items should be displayed/hidden v true if show popup part of the jcomboBox and false to hide.

Parameters: c The JComponent that is having this UI removed.