File	Doc	Category	Size	Date	Package
JComboBox.java	API Doc	Java SE 5 API	78635	Fri Aug 26 14:57:54 BST 2005	javax.swing

JComboBox

• java.lang.Object
  • java.awt.Component
    • java.awt.Container
      • javax.swing.JComponent

Fields Summary
private static final String	uiClassID
protected ComboBoxModel	dataModel This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected ListCellRenderer	renderer This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected ComboBoxEditor	editor This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected int	maximumRowCount This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected boolean	isEditable This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected KeySelectionManager	keySelectionManager This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected String	actionCommand This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected boolean	lightWeightPopupEnabled This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
protected Object	selectedItemReminder This protected field is implementation specific. Do not access directly or override.
private Object	prototypeDisplayValue
private boolean	firingActionEvent
private boolean	selectingItem
private Action	action
private PropertyChangeListener	actionPropertyChangeListener

Constructors Summary
public JComboBox(ComboBoxModel aModel) Creates a JComboBox that takes it's items from an existing ComboBoxModel. Since the ComboBoxModel is provided, a combo box created using this constructor does not create a default combo box model and may impact how the insert, remove and add methods behave. param aModel the ComboBoxModel that provides the displayed list of items see DefaultComboBoxModel super(); setModel(aModel); init();
public JComboBox(Object[] items) Creates a JComboBox that contains the elements in the specified array. By default the first item in the array (and therefore the data model) becomes selected. param items an array of objects to insert into the combo box see DefaultComboBoxModel super(); setModel(new DefaultComboBoxModel(items)); init();
public JComboBox(Vector items) Creates a JComboBox that contains the elements in the specified Vector. By default the first item in the vector and therefore the data model) becomes selected. param items an array of vectors to insert into the combo box see DefaultComboBoxModel super(); setModel(new DefaultComboBoxModel(items)); init();
public JComboBox() Creates a JComboBox with a default data model. The default data model is an empty list of objects. Use addItem to add items. By default the first item in the data model becomes selected. see DefaultComboBoxModel super(); setModel(new DefaultComboBoxModel()); init();

Methods Summary
public void	actionPerformed(java.awt.event.ActionEvent e) This method is public as an implementation side effect. do not call or override. Object newItem = getEditor().getItem(); setPopupVisible(false); getModel().setSelectedItem(newItem); String oldCommand = getActionCommand(); setActionCommand("comboBoxEdited"); fireActionEvent(); setActionCommand(oldCommand);
public void	addActionListener(java.awt.event.ActionListener l) Adds an ActionListener. The ActionListener will receive an ActionEvent when a selection has been made. If the combo box is editable, then an ActionEvent will be fired when editing has stopped. param l the ActionListener that is to be notified see #setSelectedItem listenerList.add(ActionListener.class,l);
public void	addItem(java.lang.Object anObject) Adds an item to the item list. This method works only if the JComboBox uses a mutable data model. Warning: Focus and keyboard navigation problems may arise if you add duplicate String objects. A workaround is to add new objects instead of String objects and make sure that the toString() method is defined. For example: comboBox.addItem(makeObj("Item 1")); comboBox.addItem(makeObj("Item 1")); ... private Object makeObj(final String item) { return new Object() { public String toString() { return item; } }; } param anObject the Object to add to the list see MutableComboBoxModel checkMutableComboBoxModel(); ((MutableComboBoxModel)dataModel).addElement(anObject);
public void	addItemListener(java.awt.event.ItemListener aListener) Adds an ItemListener. aListener will receive one or two ItemEvents when the selected item changes. param aListener the ItemListener that is to be notified see #setSelectedItem listenerList.add(ItemListener.class,aListener);
public void	addPopupMenuListener(javax.swing.event.PopupMenuListener l) Adds a PopupMenu listener which will listen to notification messages from the popup portion of the combo box. For all standard look and feels shipped with Java 2, the popup list portion of combo box is implemented as a JPopupMenu. A custom look and feel may not implement it this way and will therefore not receive the notification. param l the PopupMenuListener to add since 1.4 listenerList.add(PopupMenuListener.class,l);
void	checkMutableComboBoxModel() Checks that the dataModel is an instance of MutableComboBoxModel. If not, it throws an exception. exception RuntimeException if dataModel is not an instance of MutableComboBoxModel. if ( !(dataModel instanceof MutableComboBoxModel) ) throw new RuntimeException("Cannot use this method with a non-Mutable data model.");
public void	configureEditor(javax.swing.ComboBoxEditor anEditor, java.lang.Object anItem) Initializes the editor with the specified item. param anEditor the ComboBoxEditor that displays the list item in the combo box field and allows it to be edited param anItem the object to display and edit in the field anEditor.setItem(anItem);
protected void	configurePropertiesFromAction(javax.swing.Action a) Factory method which sets the ActionEvent source's properties according to values from the Action instance. The properties which are set may differ for subclasses. By default, the properties which get set are Enabled and ToolTipText. param a the Action from which to get the properties, or null since 1.3 see Action see #setAction setEnabled((a!=null?a.isEnabled():true)); setToolTipText((a!=null?(String)a.getValue(Action.SHORT_DESCRIPTION):null));
public void	contentsChanged(javax.swing.event.ListDataEvent e) This method is public as an implementation side effect. do not call or override. Object oldSelection = selectedItemReminder; Object newSelection = dataModel.getSelectedItem(); if (oldSelection == null || !oldSelection.equals(newSelection)) { selectedItemChanged(); if (!selectingItem) { fireActionEvent(); } }
protected java.beans.PropertyChangeListener	createActionPropertyChangeListener(javax.swing.Action a) Factory method which creates the PropertyChangeListener used to update the ActionEvent source as properties change on its Action instance. Subclasses may override this in order to provide their own PropertyChangeListener if the set of properties which should be kept up to date differs from the default properties (Text, Icon, Enabled, ToolTipText). Note that PropertyChangeListeners should avoid holding strong references to the ActionEvent source, as this may hinder garbage collection of the ActionEvent source and all components in its containment hierarchy. since 1.3 see Action see #setAction return new AbstractActionPropertyChangeListener(this, a) { public void propertyChange(PropertyChangeEvent e) { String propertyName = e.getPropertyName(); JComboBox comboBox = (JComboBox)getTarget(); if (comboBox == null) { //WeakRef GC'ed in 1.2 Action action = (Action)e.getSource(); action.removePropertyChangeListener(this); } else { if (e.getPropertyName().equals(Action.SHORT_DESCRIPTION)) { String text = (String) e.getNewValue(); comboBox.setToolTipText(text); } else if (propertyName.equals("enabled")) { Boolean enabledState = (Boolean) e.getNewValue(); comboBox.setEnabled(enabledState.booleanValue()); comboBox.repaint(); } } } };
protected javax.swing.JComboBox$KeySelectionManager	createDefaultKeySelectionManager() Returns an instance of the default key-selection manager. return the KeySelectionManager currently used by the list see #setKeySelectionManager return new DefaultKeySelectionManager();
protected void	fireActionEvent() Notifies all listeners that have registered interest for notification on this event type. see EventListenerList if (!firingActionEvent) { // Set flag to ensure that an infinite loop is not created firingActionEvent = true; ActionEvent e = null; // Guaranteed to return a non-null array Object[] listeners = listenerList.getListenerList(); long mostRecentEventTime = EventQueue.getMostRecentEventTime(); int modifiers = 0; AWTEvent currentEvent = EventQueue.getCurrentEvent(); if (currentEvent instanceof InputEvent) { modifiers = ((InputEvent)currentEvent).getModifiers(); } else if (currentEvent instanceof ActionEvent) { modifiers = ((ActionEvent)currentEvent).getModifiers(); } // Process the listeners last to first, notifying // those that are interested in this event for ( int i = listeners.length-2; i>=0; i-=2 ) { if ( listeners[i]==ActionListener.class ) { // Lazily create the event: if ( e == null ) e = new ActionEvent(this,ActionEvent.ACTION_PERFORMED, getActionCommand(), mostRecentEventTime, modifiers); ((ActionListener)listeners[i+1]).actionPerformed(e); } } firingActionEvent = false; }
protected void	fireItemStateChanged(java.awt.event.ItemEvent e) Notifies all listeners that have registered interest for notification on this event type. param e the event of interest see EventListenerList // Guaranteed to return a non-null array Object[] listeners = listenerList.getListenerList(); // Process the listeners last to first, notifying // those that are interested in this event for ( int i = listeners.length-2; i>=0; i-=2 ) { if ( listeners[i]==ItemListener.class ) { // Lazily create the event: // if (changeEvent == null) // changeEvent = new ChangeEvent(this); ((ItemListener)listeners[i+1]).itemStateChanged(e); } }
public void	firePopupMenuCanceled() Notifies PopupMenuListeners that the popup portion of the combo box has been canceled. This method is public but should not be called by anything other than the UI delegate. see #addPopupMenuListener since 1.4 Object[] listeners = listenerList.getListenerList(); PopupMenuEvent e=null; for (int i = listeners.length-2; i>=0; i-=2) { if (listeners[i]==PopupMenuListener.class) { if (e == null) e = new PopupMenuEvent(this); ((PopupMenuListener)listeners[i+1]).popupMenuCanceled(e); } }
public void	firePopupMenuWillBecomeInvisible() Notifies PopupMenuListeners that the popup portion of the combo box has become invisible. This method is public but should not be called by anything other than the UI delegate. see #addPopupMenuListener since 1.4 Object[] listeners = listenerList.getListenerList(); PopupMenuEvent e=null; for (int i = listeners.length-2; i>=0; i-=2) { if (listeners[i]==PopupMenuListener.class) { if (e == null) e = new PopupMenuEvent(this); ((PopupMenuListener)listeners[i+1]).popupMenuWillBecomeInvisible(e); } }
public void	firePopupMenuWillBecomeVisible() Notifies PopupMenuListeners that the popup portion of the combo box will become visible. This method is public but should not be called by anything other than the UI delegate. see #addPopupMenuListener since 1.4 Object[] listeners = listenerList.getListenerList(); PopupMenuEvent e=null; for (int i = listeners.length-2; i>=0; i-=2) { if (listeners[i]==PopupMenuListener.class) { if (e == null) e = new PopupMenuEvent(this); ((PopupMenuListener)listeners[i+1]).popupMenuWillBecomeVisible(e); } }
public javax.accessibility.AccessibleContext	getAccessibleContext() Gets the AccessibleContext associated with this JComboBox. For combo boxes, the AccessibleContext takes the form of an AccessibleJComboBox. A new AccessibleJComboBox instance is created if necessary. return an AccessibleJComboBox that serves as the AccessibleContext of this JComboBox if ( accessibleContext == null ) { accessibleContext = new AccessibleJComboBox(); } return accessibleContext;
public javax.swing.Action	getAction() Returns the currently set Action for this ActionEvent source, or null if no Action is set. return the Action for this ActionEvent source; or null since 1.3 see Action see #setAction return action;
public java.lang.String	getActionCommand() Returns the action command that is included in the event sent to action listeners. return the string containing the "command" that is sent to action listeners. return actionCommand;
public java.awt.event.ActionListener[]	getActionListeners() Returns an array of all the ActionListeners added to this JComboBox with addActionListener(). return all of the ActionListeners added or an empty array if no listeners have been added since 1.4 return (ActionListener[])listenerList.getListeners( ActionListener.class);
public javax.swing.ComboBoxEditor	getEditor() Returns the editor used to paint and edit the selected item in the JComboBox field. return the ComboBoxEditor that displays the selected item return editor;
public java.lang.Object	getItemAt(int index) Returns the list item at the specified index. If index is out of range (less than zero or greater than or equal to size) it will return null. param index an integer indicating the list position, where the first item starts at zero return the Object at that list position; or null if out of range return dataModel.getElementAt(index);
public int	getItemCount() Returns the number of items in the list. return an integer equal to the number of items in the list return dataModel.getSize();
public java.awt.event.ItemListener[]	getItemListeners() Returns an array of all the ItemListeners added to this JComboBox with addItemListener(). return all of the ItemListeners added or an empty array if no listeners have been added since 1.4 return (ItemListener[])listenerList.getListeners(ItemListener.class);
public javax.swing.JComboBox$KeySelectionManager	getKeySelectionManager() Returns the list's key-selection manager. return the KeySelectionManager currently in use return keySelectionManager;
public int	getMaximumRowCount() Returns the maximum number of items the combo box can display without a scrollbar return an integer specifying the maximum number of items that are displayed in the list before using a scrollbar return maximumRowCount;
public javax.swing.ComboBoxModel	getModel() Returns the data model currently used by the JComboBox. return the ComboBoxModel that provides the displayed list of items return dataModel;
public javax.swing.event.PopupMenuListener[]	getPopupMenuListeners() Returns an array of all the PopupMenuListeners added to this JComboBox with addPopupMenuListener(). return all of the PopupMenuListeners added or an empty array if no listeners have been added since 1.4 return (PopupMenuListener[])listenerList.getListeners( PopupMenuListener.class);
public java.lang.Object	getPrototypeDisplayValue() Returns the "prototypical display" value - an Object used for the calculation of the display height and width. return the value of the prototypeDisplayValue property see #setPrototypeDisplayValue since 1.4 return prototypeDisplayValue;
public javax.swing.ListCellRenderer	getRenderer() Returns the renderer used to display the selected item in the JComboBox field. return the ListCellRenderer that displays the selected item. return renderer;
public int	getSelectedIndex() Returns the first item in the list that matches the given item. The result is not always defined if the JComboBox allows selected items that are not in the list. Returns -1 if there is no selected item or if the user specified an item which is not in the list. return an integer specifying the currently selected list item, where 0 specifies the first item in the list; or -1 if no item is selected or if the currently selected item is not in the list Object sObject = dataModel.getSelectedItem(); int i,c; Object obj; for ( i=0,c=dataModel.getSize();i<c;i++ ) { obj = dataModel.getElementAt(i); if ( obj != null && obj.equals(sObject) ) return i; } return -1;
public java.lang.Object	getSelectedItem() Returns the current selected item. If the combo box is editable, then this value may not have been added to the combo box with addItem, insertItemAt or the data constructors. return the current selected Object see #setSelectedItem return dataModel.getSelectedItem();
public java.lang.Object[]	getSelectedObjects() Returns an array containing the selected item. This method is implemented for compatibility with ItemSelectable. return an array of Objects containing one element -- the selected item Object selectedObject = getSelectedItem(); if ( selectedObject == null ) return new Object[0]; else { Object result[] = new Object[1]; result[0] = selectedObject; return result; }
public javax.swing.plaf.ComboBoxUI	getUI() Returns the L&F object that renders this component. return the ComboBoxUI object that renders this component return(ComboBoxUI)ui;
public java.lang.String	getUIClassID() Returns the name of the L&F class that renders this component. return the string "ComboBoxUI" see JComponent#getUIClassID see UIDefaults#getUI return uiClassID;
public void	hidePopup() Causes the combo box to close its popup window. see #setPopupVisible setPopupVisible(false);
private void	init() installAncestorListener(); setOpaque(true); updateUI();
public void	insertItemAt(java.lang.Object anObject, int index) Inserts an item into the item list at a given index. This method works only if the JComboBox uses a mutable data model. param anObject the Object to add to the list param index an integer specifying the position at which to add the item see MutableComboBoxModel checkMutableComboBoxModel(); ((MutableComboBoxModel)dataModel).insertElementAt(anObject,index);
protected void	installAncestorListener() addAncestorListener(new AncestorListener(){ public void ancestorAdded(AncestorEvent event){ hidePopup();} public void ancestorRemoved(AncestorEvent event){ hidePopup();} public void ancestorMoved(AncestorEvent event){ if (event.getSource() != JComboBox.this) hidePopup(); }});
public void	intervalAdded(javax.swing.event.ListDataEvent e) This method is public as an implementation side effect. do not call or override. if (selectedItemReminder != dataModel.getSelectedItem()) { selectedItemChanged(); }
public void	intervalRemoved(javax.swing.event.ListDataEvent e) This method is public as an implementation side effect. do not call or override. contentsChanged(e);
public boolean	isEditable() Returns true if the JComboBox is editable. By default, a combo box is not editable. return true if the JComboBox is editable, else false return isEditable;
public boolean	isLightWeightPopupEnabled() Gets the value of the lightWeightPopupEnabled property. return the value of the lightWeightPopupEnabled property see #setLightWeightPopupEnabled return lightWeightPopupEnabled;
private boolean	isListener(java.lang.Class c, java.awt.event.ActionListener a) boolean isListener = false; Object[] listeners = listenerList.getListenerList(); for (int i = listeners.length-2; i>=0; i-=2) { if (listeners[i]==c && listeners[i+1]==a) { isListener=true; } } return isListener;
public boolean	isPopupVisible() Determines the visibility of the popup. return true if the popup is visible, otherwise returns false return getUI().isPopupVisible(this);
protected java.lang.String	paramString() Returns a string representation of this JComboBox. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null. return a string representation of this JComboBox String selectedItemReminderString = (selectedItemReminder != null ? selectedItemReminder.toString() : ""); String isEditableString = (isEditable ? "true" : "false"); String lightWeightPopupEnabledString = (lightWeightPopupEnabled ? "true" : "false"); return super.paramString() + ",isEditable=" + isEditableString + ",lightWeightPopupEnabled=" + lightWeightPopupEnabledString + ",maximumRowCount=" + maximumRowCount + ",selectedItemReminder=" + selectedItemReminderString;
public void	processKeyEvent(java.awt.event.KeyEvent e) Handles KeyEvents, looking for the Tab key. If the Tab key is found, the popup window is closed. param e the KeyEvent containing the keyboard key that was pressed if ( e.getKeyCode() == KeyEvent.VK_TAB ) { hidePopup(); } super.processKeyEvent(e);
public void	removeActionListener(java.awt.event.ActionListener l) Removes an ActionListener. param l the ActionListener to remove if ((l != null) && (getAction() == l)) { setAction(null); } else { listenerList.remove(ActionListener.class, l); }
public void	removeAllItems() Removes all items from the item list. checkMutableComboBoxModel(); MutableComboBoxModel model = (MutableComboBoxModel)dataModel; int size = model.getSize(); if ( model instanceof DefaultComboBoxModel ) { ((DefaultComboBoxModel)model).removeAllElements(); } else { for ( int i = 0; i < size; ++i ) { Object element = model.getElementAt( 0 ); model.removeElement( element ); } } selectedItemReminder = null; if (isEditable()) { editor.setItem(null); }
public void	removeItem(java.lang.Object anObject) Removes an item from the item list. This method works only if the JComboBox uses a mutable data model. param anObject the object to remove from the item list see MutableComboBoxModel checkMutableComboBoxModel(); ((MutableComboBoxModel)dataModel).removeElement(anObject);
public void	removeItemAt(int anIndex) Removes the item at anIndex This method works only if the JComboBox uses a mutable data model. param anIndex an int specifying the index of the item to remove, where 0 indicates the first item in the list see MutableComboBoxModel checkMutableComboBoxModel(); ((MutableComboBoxModel)dataModel).removeElementAt( anIndex );
public void	removeItemListener(java.awt.event.ItemListener aListener) Removes an ItemListener. param aListener the ItemListener to remove listenerList.remove(ItemListener.class,aListener);
public void	removePopupMenuListener(javax.swing.event.PopupMenuListener l) Removes a PopupMenuListener. param l the PopupMenuListener to remove see #addPopupMenuListener since 1.4 listenerList.remove(PopupMenuListener.class,l);
public boolean	selectWithKeyChar(char keyChar) Selects the list item that corresponds to the specified keyboard character and returns true, if there is an item corresponding to that character. Otherwise, returns false. param keyChar a char, typically this is a keyboard key typed by the user int index; if ( keySelectionManager == null ) keySelectionManager = createDefaultKeySelectionManager(); index = keySelectionManager.selectionForKey(keyChar,getModel()); if ( index != -1 ) { setSelectedIndex(index); return true; } else return false;
protected void	selectedItemChanged() This protected method is implementation specific. Do not access directly or override. if (selectedItemReminder != null ) { fireItemStateChanged(new ItemEvent(this,ItemEvent.ITEM_STATE_CHANGED, selectedItemReminder, ItemEvent.DESELECTED)); } // set the new selected item. selectedItemReminder = dataModel.getSelectedItem(); if (selectedItemReminder != null ) { fireItemStateChanged(new ItemEvent(this,ItemEvent.ITEM_STATE_CHANGED, selectedItemReminder, ItemEvent.SELECTED)); }
public void	setAction(javax.swing.Action a) Sets the Action for the ActionEvent source. The new Action replaces any previously set Action but does not affect ActionListeners independently added with addActionListener. If the Action is already a registered ActionListener for the ActionEvent source, it is not re-registered. A side-effect of setting the Action is that the ActionEvent source's properties are immedately set from the values in the Action (performed by the method configurePropertiesFromAction) and subsequently updated as the Action's properties change (via a PropertyChangeListener created by the method createActionPropertyChangeListener. param a the Action for the JComboBox, or null. since 1.3 see Action see #getAction see #configurePropertiesFromAction see #createActionPropertyChangeListener beaninfo bound: true attribute: visualUpdate true description: the Action instance connected with this ActionEvent source Action oldValue = getAction(); if (action==null || !action.equals(a)) { action = a; if (oldValue!=null) { removeActionListener(oldValue); oldValue.removePropertyChangeListener(actionPropertyChangeListener); actionPropertyChangeListener = null; } configurePropertiesFromAction(action); if (action!=null) { // Don't add if it is already a listener if (!isListener(ActionListener.class, action)) { addActionListener(action); } // Reverse linkage: actionPropertyChangeListener = createActionPropertyChangeListener(action); action.addPropertyChangeListener(actionPropertyChangeListener); } firePropertyChange("action", oldValue, action); revalidate(); repaint(); }
public void	setActionCommand(java.lang.String aCommand) Sets the action command that should be included in the event sent to action listeners. param aCommand a string containing the "command" that is sent to action listeners; the same listener can then do different things depending on the command it receives actionCommand = aCommand;
public void	setEditable(boolean aFlag) Determines whether the JComboBox field is editable. An editable JComboBox allows the user to type into the field or selected an item from the list to initialize the field, after which it can be edited. (The editing affects only the field, the list item remains intact.) A non editable JComboBox displays the selected item in the field, but the selection cannot be modified. param aFlag a boolean value, where true indicates that the field is editable beaninfo bound: true preferred: true description: If true, the user can type a new value in the combo box. boolean oldFlag = isEditable; isEditable = aFlag; firePropertyChange( "editable", oldFlag, isEditable );
public void	setEditor(javax.swing.ComboBoxEditor anEditor) Sets the editor used to paint and edit the selected item in the JComboBox field. The editor is used only if the receiving JComboBox is editable. If not editable, the combo box uses the renderer to paint the selected item. param anEditor the ComboBoxEditor that displays the selected item see #setRenderer beaninfo bound: true expert: true description: The editor that combo box uses to edit the current value ComboBoxEditor oldEditor = editor; if ( editor != null ) { editor.removeActionListener(this); } editor = anEditor; if ( editor != null ) { editor.addActionListener(this); } firePropertyChange( "editor", oldEditor, editor );
public void	setEnabled(boolean b) Enables the combo box so that items can be selected. When the combo box is disabled, items cannot be selected and values cannot be typed into its field (if it is editable). param b a boolean value, where true enables the component and false disables it beaninfo bound: true preferred: true description: Whether the combo box is enabled. super.setEnabled(b); firePropertyChange( "enabled", !isEnabled(), isEnabled() );
public void	setKeySelectionManager(javax.swing.JComboBox$KeySelectionManager aManager) Sets the object that translates a keyboard character into a list selection. Typically, the first selection with a matching first character becomes the selected item. beaninfo expert: true description: The objects that changes the selection when a key is pressed. keySelectionManager = aManager;
public void	setLightWeightPopupEnabled(boolean aFlag) Sets the lightWeightPopupEnabled property, which provides a hint as to whether or not a lightweight Component should be used to contain the JComboBox, versus a heavyweight Component such as a Panel or a Window. The decision of lightweight versus heavyweight is ultimately up to the JComboBox. Lightweight windows are more efficient than heavyweight windows, but lightweight and heavyweight components do not mix well in a GUI. If your application mixes lightweight and heavyweight components, you should disable lightweight popups. The default value for the lightWeightPopupEnabled property is true, unless otherwise specified by the look and feel. Some look and feels always use heavyweight popups, no matter what the value of this property. See the article Mixing Heavy and Light Components on The Swing Connection This method fires a property changed event. param aFlag if true, lightweight popups are desired beaninfo bound: true expert: true description: Set to false to require heavyweight popups. boolean oldFlag = lightWeightPopupEnabled; lightWeightPopupEnabled = aFlag; firePropertyChange("lightWeightPopupEnabled", oldFlag, lightWeightPopupEnabled);
public void	setMaximumRowCount(int count) Sets the maximum number of rows the JComboBox displays. If the number of objects in the model is greater than count, the combo box uses a scrollbar. param count an integer specifying the maximum number of items to display in the list before using a scrollbar beaninfo bound: true preferred: true description: The maximum number of rows the popup should have int oldCount = maximumRowCount; maximumRowCount = count; firePropertyChange( "maximumRowCount", oldCount, maximumRowCount );
public void	setModel(javax.swing.ComboBoxModel aModel) Sets the data model that the JComboBox uses to obtain the list of items. param aModel the ComboBoxModel that provides the displayed list of items beaninfo bound: true description: Model that the combo box uses to get data to display. ComboBoxModel oldModel = dataModel; if (oldModel != null) { oldModel.removeListDataListener(this); } dataModel = aModel; dataModel.addListDataListener(this); // set the current selected item. selectedItemReminder = dataModel.getSelectedItem(); firePropertyChange( "model", oldModel, dataModel);
public void	setPopupVisible(boolean v) Sets the visibility of the popup. getUI().setPopupVisible(this, v);
public void	setPrototypeDisplayValue(java.lang.Object prototypeDisplayValue) Sets the prototype display value used to calculate the size of the display for the UI portion. If a prototype display value is specified, the preferred size of the combo box is calculated by configuring the renderer with the prototype display value and obtaining its preferred size. Specifying the preferred display value is often useful when the combo box will be displaying large amounts of data. If no prototype display value has been specified, the renderer must be configured for each value from the model and its preferred size obtained, which can be relatively expensive. param prototypeDisplayValue see #getPrototypeDisplayValue since 1.4 beaninfo bound: true attribute: visualUpdate true description: The display prototype value, used to compute display width and height. Object oldValue = this.prototypeDisplayValue; this.prototypeDisplayValue = prototypeDisplayValue; firePropertyChange("prototypeDisplayValue", oldValue, prototypeDisplayValue);
public void	setRenderer(javax.swing.ListCellRenderer aRenderer) Sets the renderer that paints the list items and the item selected from the list in the JComboBox field. The renderer is used if the JComboBox is not editable. If it is editable, the editor is used to render and edit the selected item. The default renderer displays a string or an icon. Other renderers can handle graphic images and composite items. To display the selected item, aRenderer.getListCellRendererComponent is called, passing the list object and an index of -1. param aRenderer the ListCellRenderer that displays the selected item see #setEditor beaninfo bound: true expert: true description: The renderer that paints the item selected in the list. ListCellRenderer oldRenderer = renderer; renderer = aRenderer; firePropertyChange( "renderer", oldRenderer, renderer ); invalidate();
public void	setSelectedIndex(int anIndex) Selects the item at index anIndex. param anIndex an integer specifying the list item to select, where 0 specifies the first item in the list and -1 indicates no selection exception IllegalArgumentException if anIndex < -1 or anIndex is greater than or equal to size beaninfo preferred: true description: The item at index is selected. int size = dataModel.getSize(); if ( anIndex == -1 ) { setSelectedItem( null ); } else if ( anIndex < -1 || anIndex >= size ) { throw new IllegalArgumentException("setSelectedIndex: " + anIndex + " out of bounds"); } else { setSelectedItem(dataModel.getElementAt(anIndex)); }
public void	setSelectedItem(java.lang.Object anObject) Sets the selected item in the combo box display area to the object in the argument. If anObject is in the list, the display area shows anObject selected. If anObject is not in the list and the combo box is uneditable, it will not change the current selection. For editable combo boxes, the selection will change to anObject. If this constitutes a change in the selected item, ItemListeners added to the combo box will be notified with one or two ItemEvents. If there is a current selected item, an ItemEvent will be fired and the state change will be ItemEvent.DESELECTED. If anObject is in the list and is not currently selected then an ItemEvent will be fired and the state change will be ItemEvent.SELECTED. ActionListeners added to the combo box will be notified with an ActionEvent when this method is called. param anObject the list object to select; use null to clear the selection beaninfo preferred: true description: Sets the selected item in the JComboBox. Object oldSelection = selectedItemReminder; if (oldSelection == null || !oldSelection.equals(anObject)) { if (anObject != null && !isEditable()) { // For non editable combo boxes, an invalid selection // will be rejected. boolean found = false; for (int i = 0; i < dataModel.getSize(); i++) { if (anObject.equals(dataModel.getElementAt(i))) { found = true; break; } } if (!found) { return; } } // Must toggle the state of this flag since this method // call may result in ListDataEvents being fired. selectingItem = true; dataModel.setSelectedItem(anObject); selectingItem = false; if (selectedItemReminder != dataModel.getSelectedItem()) { // in case a users implementation of ComboBoxModel // doesn't fire a ListDataEvent when the selection // changes. selectedItemChanged(); } } fireActionEvent();
public void	setUI(javax.swing.plaf.ComboBoxUI ui) Sets the L&F object that renders this component. param ui the ComboBoxUI L&F object see UIDefaults#getUI beaninfo bound: true hidden: true attribute: visualUpdate true description: The UI object that implements the Component's LookAndFeel. super.setUI(ui);
public void	showPopup() Causes the combo box to display its popup window. see #setPopupVisible setPopupVisible(true);
public void	updateUI() Resets the UI property to a value from the current look and feel. see JComponent#updateUI setUI((ComboBoxUI)UIManager.getUI(this));
private void	writeObject(java.io.ObjectOutputStream s) See readObject and writeObject in JComponent for more information about serialization in Swing. s.defaultWriteObject(); if (getUIClassID().equals(uiClassID)) { byte count = JComponent.getWriteObjCounter(this); JComponent.setWriteObjCounter(this, --count); if (count == 0 && ui != null) { ui.installUI(this); } }