- Direct Known Subclasses:
- MetalComboBoxUI,- SynthComboBoxUI
The combo box is a compound component which means that it is an aggregate of many simpler components. This class creates and manages the listeners on the combo box and the combo box model. These listeners update the user interface in response to changes in the properties and state of the combo box.
 All event handling is handled by listener classes created with the
 createxxxListener() methods and internal classes.
 You can change the behavior of this class by overriding the
 createxxxListener() methods and supplying your own
 event listeners or subclassing from the ones supplied in this class.
 
 For adding specific actions,
 override installKeyboardActions to add actions in response to
 KeyStroke bindings. See the article How to Use Key Bindings
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Nested Class SummaryNested ClassesModifier and TypeClassDescriptionclassThis layout manager handles the 'standard' layout of combo boxes.classThis listener hides the popup when the focus is lost.classThis listener watches for changes to the selection in the combo box.classThis listener checks to see if the key event isn't a navigation key.classThis listener watches for changes in theComboBoxModel.classThis listener watches for bound properties that have changed in the combo box.
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Field SummaryFieldsModifier and TypeFieldDescriptionprotected JButtonThe arrow button that invokes the popup.protected DimensionThe cached minimum preferred size.The instance ofJComboBox.protected CellRendererPaneUsed to render the currently selected item in the combo box.protected ComponentThe Component that theComboBoxEditoruses for editing.protected FocusListenerThis protected field is implementation specific.protected booleanThis protected field is implementation specific.protected booleanThe flag for recalculating the minimum preferred size.protected ItemListenerThis protected field is implementation specific.protected KeyListenerThis protected field is implementation specific.This list is for drawing the current item in the combo box.protected ListDataListenerThis protected field is implementation specific.protected InsetsIf specified, these insets act as padding around the cell renderer when laying out and painting the "selected" item in the combo box.protected ComboPopupThe implementation ofComboPopupthat is used to show the popup.protected KeyListenerTheKeyListenerlistens to events.protected MouseListenerTheMouseListenerlistens to events.protected MouseMotionListenerTheMouseMotionListenerlistens to events.protected PropertyChangeListenerThis protected field is implementation specific.protected booleanIndicates whether or not the combo box button should be square.
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Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptionvoidThis public method is implementation specific and should be private.voidThis public method is implementation specific and should be private.protected voidThis protected method is implementation specific and should be private.protected JButtonCreates a button which will be used as the control to show or hide the popup portion of the combo box.protected ComboBoxEditorCreates the default editor that will be used in editable combo boxes.protected FocusListenerCreates aFocusListenerwhich will be added to the combo box.protected ItemListenerCreates anItemListenerwhich will be added to the combo box.protected KeyListenerCreates aKeyListenerwhich will be added to the combo box.protected LayoutManagerCreates a layout manager for managing the components which make up the combo box.protected ListDataListenerCreates a list data listener which will be added to theComboBoxModel.protected ComboPopupCreates the popup portion of the combo box.protected PropertyChangeListenerCreates aPropertyChangeListenerwhich will be added to the combo box.protected ListCellRenderer<Object> Creates the default renderer that will be used in a non-editiable combo box.static ComponentUIConstructs a new instance ofBasicComboBoxUI.intgetBaseline(JComponent c, int width, int height) Returns the baseline.Returns an enum indicating how the baseline of the component changes as the size changes.protected DimensionReturn the default size of an empty display area of the combo box using the current renderer and font.protected DimensionReturns the calculated size of the display area.protected InsetsGets the insets from the JComboBox.The minimum size is the size of the display area plus insets plus the button.protected DimensiongetSizeForComponent(Component comp) Returns the size a component would have if used as a cell renderer.protected voidCreates and initializes the components which make up the aggregate combo box.protected voidInstalls the default colors, default font, default renderer, and default editor into the JComboBox.protected voidAdds keyboard actions to the JComboBox.protected voidCreates and installs listeners for the combo box and its model.booleanisFocusTraversable(JComboBox<?> c) Determines if the JComboBox is focus traversable.protected booleanisNavigationKey(int keyCode) Returns whether or not the supplied keyCode maps to a key that is used for navigation.booleanisPopupVisible(JComboBox<?> c) Tells if the popup is visible or not.voidpaintCurrentValue(Graphics g, Rectangle bounds, boolean hasFocus) Paints the currently selected item.voidpaintCurrentValueBackground(Graphics g, Rectangle bounds, boolean hasFocus) Paints the background of the currently selected item.protected RectangleReturns the area that is reserved for drawing the currently selected item.voidThis public method is implementation specific and should be private.protected voidSelects the next item in the list.protected voidSelects the previous item in the list.voidsetPopupVisible(JComboBox<?> c, boolean v) Hides the popup.protected voidHides the popup if it is showing and shows the popup if it is hidden.voidThis public method is implementation specific and should be private.protected voidThis protected method is implementation specific and should be private.protected voidThe aggregate components which comprise the combo box are unregistered and uninitialized.protected voidUninstalls the default colors, default font, default renderer, and default editor from the combo box.protected voidRemoves the focus InputMap and ActionMap.protected voidRemoves the installed listeners from the combo box and its model.Methods declared in class javax.swing.plaf.ComponentUIcontains, getAccessibleChild, getAccessibleChildrenCount, getMaximumSize, getPreferredSize, installUI, paint, uninstallUI, update
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Field Details- 
comboBoxThe instance ofJComboBox.
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hasFocusprotected boolean hasFocusThis protected field is implementation specific. Do not access directly or override.
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listBoxThis list is for drawing the current item in the combo box.
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currentValuePaneUsed to render the currently selected item in the combo box. It doesn't have anything to do with the popup's rendering.
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popupThe implementation ofComboPopupthat is used to show the popup.
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editorThe Component that theComboBoxEditoruses for editing.
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arrowButtonThe arrow button that invokes the popup.
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keyListenerThis protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
 
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focusListenerThis protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
 
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propertyChangeListenerThis protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
 
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itemListenerThis protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
 
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popupMouseListenerTheMouseListenerlistens to events.
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popupMouseMotionListenerTheMouseMotionListenerlistens to events.
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popupKeyListenerTheKeyListenerlistens to events.
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listDataListenerThis protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
 
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isMinimumSizeDirtyprotected boolean isMinimumSizeDirtyThe flag for recalculating the minimum preferred size.
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cachedMinimumSizeThe cached minimum preferred size.
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squareButtonprotected boolean squareButtonIndicates whether or not the combo box button should be square. If square, then the width and height are equal, and are both set to the height of the combo minus appropriate insets.- Since:
- 1.7
 
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paddingIf specified, these insets act as padding around the cell renderer when laying out and painting the "selected" item in the combo box. These insets add to those specified by the cell renderer.- Since:
- 1.7
 
 
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Constructor Details- 
BasicComboBoxUIpublic BasicComboBoxUI()Constructs aBasicComboBoxUI.
 
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Method Details- 
createUIConstructs a new instance ofBasicComboBoxUI.- Parameters:
- c- a component
- Returns:
- a new instance of BasicComboBoxUI
 
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installDefaultsprotected void installDefaults()Installs the default colors, default font, default renderer, and default editor into the JComboBox.
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installListenersprotected void installListeners()Creates and installs listeners for the combo box and its model. This method is called when the UI is installed.
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uninstallDefaultsprotected void uninstallDefaults()Uninstalls the default colors, default font, default renderer, and default editor from the combo box.
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uninstallListenersprotected void uninstallListeners()Removes the installed listeners from the combo box and its model. The number and types of listeners removed and in this method should be the same that was added ininstallListeners
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createPopupCreates the popup portion of the combo box.- Returns:
- an instance of ComboPopup
- See Also:
 
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createKeyListenerCreates aKeyListenerwhich will be added to the combo box. If this method returns null then it will not be added to the combo box.- Returns:
- an instance KeyListeneror null
 
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createFocusListenerCreates aFocusListenerwhich will be added to the combo box. If this method returns null then it will not be added to the combo box.- Returns:
- an instance of a FocusListeneror null
 
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createListDataListenerCreates a list data listener which will be added to theComboBoxModel. If this method returns null then it will not be added to the combo box model.- Returns:
- an instance of a ListDataListeneror null
 
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createItemListenerCreates anItemListenerwhich will be added to the combo box. If this method returns null then it will not be added to the combo box.Subclasses may override this method to return instances of their own ItemEvent handlers. - Returns:
- an instance of an ItemListeneror null
 
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createPropertyChangeListenerCreates aPropertyChangeListenerwhich will be added to the combo box. If this method returns null then it will not be added to the combo box.- Returns:
- an instance of a PropertyChangeListeneror null
 
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createLayoutManagerCreates a layout manager for managing the components which make up the combo box.- Returns:
- an instance of a layout manager
 
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createRendererCreates the default renderer that will be used in a non-editiable combo box. A default renderer will used only if a renderer has not been explicitly set withsetRenderer.- Returns:
- a ListCellRenderused for the combo box
- See Also:
 
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createEditorCreates the default editor that will be used in editable combo boxes. A default editor will be used only if an editor has not been explicitly set withsetEditor.- Returns:
- a ComboBoxEditorused for the combo box
- See Also:
 
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installComponentsprotected void installComponents()Creates and initializes the components which make up the aggregate combo box. This method is called as part of the UI installation process.
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uninstallComponentsprotected void uninstallComponents()The aggregate components which comprise the combo box are unregistered and uninitialized. This method is called as part of the UI uninstallation process.
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addEditorpublic void addEditor()This public method is implementation specific and should be private. do not call or override. To implement a specific editor create a customComboBoxEditor- See Also:
 
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removeEditorpublic void removeEditor()This public method is implementation specific and should be private. do not call or override.- See Also:
 
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configureEditorprotected void configureEditor()This protected method is implementation specific and should be private. do not call or override.- See Also:
 
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unconfigureEditorprotected void unconfigureEditor()This protected method is implementation specific and should be private. Do not call or override.- See Also:
 
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configureArrowButtonpublic void configureArrowButton()This public method is implementation specific and should be private. Do not call or override.- See Also:
 
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unconfigureArrowButtonpublic void unconfigureArrowButton()This public method is implementation specific and should be private. Do not call or override.- See Also:
 
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createArrowButtonCreates a button which will be used as the control to show or hide the popup portion of the combo box.- Returns:
- a button which represents the popup control
 
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isPopupVisibleTells if the popup is visible or not.- Specified by:
- isPopupVisiblein class- ComboBoxUI
- Parameters:
- c- a- JComboBox
- Returns:
- true if popup of the JComboBoxis visible
 
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setPopupVisibleHides the popup.- Specified by:
- setPopupVisiblein class- ComboBoxUI
- Parameters:
- c- a- JComboBox
- v- a- booleandetermining the visibility of the popup
 
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isFocusTraversableDetermines if the JComboBox is focus traversable. If the JComboBox is editable this returns false, otherwise it returns true.- Specified by:
- isFocusTraversablein class- ComboBoxUI
- Parameters:
- c- a- JComboBox
- Returns:
- true if the given JComboBoxis traversable
 
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getMinimumSizeThe minimum size is the size of the display area plus insets plus the button.- Overrides:
- getMinimumSizein class- ComponentUI
- Parameters:
- c- the component whose minimum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
- Returns:
- a Dimensionobject ornull
- See Also:
 
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getBaselineReturns the baseline.- Overrides:
- getBaselinein class- ComponentUI
- Parameters:
- c-- JComponentbaseline is being requested for
- width- the width to get the baseline for
- height- the height to get the baseline for
- Returns:
- baseline or a value < 0 indicating there is no reasonable baseline
- Throws:
- NullPointerException- if- cis- null
- IllegalArgumentException- if width or height is < 0
- Since:
- 1.6
- See Also:
 
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getBaselineResizeBehaviorReturns an enum indicating how the baseline of the component changes as the size changes.- Overrides:
- getBaselineResizeBehaviorin class- ComponentUI
- Parameters:
- c-- JComponentto return baseline resize behavior for
- Returns:
- an enum indicating how the baseline changes as the component size changes
- Throws:
- NullPointerException- if- cis- null
- Since:
- 1.6
- See Also:
 
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selectNextPossibleValueprotected void selectNextPossibleValue()Selects the next item in the list. It won't change the selection if the currently selected item is already the last item.
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selectPreviousPossibleValueprotected void selectPreviousPossibleValue()Selects the previous item in the list. It won't change the selection if the currently selected item is already the first item.
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toggleOpenCloseprotected void toggleOpenClose()Hides the popup if it is showing and shows the popup if it is hidden.
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rectangleForCurrentValueReturns the area that is reserved for drawing the currently selected item.- Returns:
- the area that is reserved for drawing the currently selected item
 
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getInsetsGets the insets from the JComboBox.- Returns:
- the insets
 
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paintCurrentValuePaints the currently selected item.- Parameters:
- g- an instance of- Graphics
- bounds- a bounding rectangle to render to
- hasFocus- is focused
 
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paintCurrentValueBackgroundPaints the background of the currently selected item.- Parameters:
- g- an instance of- Graphics
- bounds- a bounding rectangle to render to
- hasFocus- is focused
 
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getDefaultSizeReturn the default size of an empty display area of the combo box using the current renderer and font.- Returns:
- the size of an empty display area
- See Also:
 
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getDisplaySizeReturns the calculated size of the display area. The display area is the portion of the combo box in which the selected item is displayed. This method will use the prototype display value if it has been set.For combo boxes with a non trivial number of items, it is recommended to use a prototype display value to significantly speed up the display size calculation. - Returns:
- the size of the display area calculated from the combo box items
- See Also:
 
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getSizeForComponentReturns the size a component would have if used as a cell renderer.- Parameters:
- comp- a- Componentto check
- Returns:
- size of the component
- Since:
- 1.7
 
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installKeyboardActionsprotected void installKeyboardActions()Adds keyboard actions to the JComboBox. Actions on enter and esc are already supplied. Add more actions as you need them.
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uninstallKeyboardActionsprotected void uninstallKeyboardActions()Removes the focus InputMap and ActionMap.
 
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