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Eclipse Rich Ajax Platform
Release 1.2

org.eclipse.swt.widgets
Class Combo

java.lang.Object
  extended by

org.eclipse.swt.widgets.Widget
      extended by

org.eclipse.swt.widgets.Control
          extended by

org.eclipse.swt.widgets.Scrollable
              extended by

org.eclipse.swt.widgets.Composite
                  extended by
org.eclipse.swt.widgets.Combo
All Implemented Interfaces:
Adaptable

public class Combo
extends Composite

Instances of this class are controls that allow the user to choose an item from a list of items, or optionally enter a new value by typing it into an editable text field. Often, Combos are used in the same place where a single selection List widget could be used but space is limited. A Combo takes less space than a List widget and shows similar information.

Note: Since Combos can contain both a list and an editable text field, it is possible to confuse methods which access one versus the other (compare for example, clearSelection() and deselectAll()). The API documentation is careful to indicate either "the receiver's list" or the "the receiver's text field" to distinguish between the two cases.

Note that although this class is a subclass of Composite, it does not make sense to add children to it, or set a layout on it.

Styles:
DROP_DOWN, READ_ONLY
Events:
DefaultSelection, Modify, Selection

IMPORTANT: This class is not intended to be subclassed.

Since:
1.0
See Also:
List

Constructor Summary
Combo ( Composite parent, int style)
          Constructs a new instance of this class given its parent and a style value describing its behavior and appearance.
 
Method Summary
 void add ( String string)
          Adds the argument to the end of the receiver's list.
 void add ( String string, int index)
          Adds the argument to the receiver's list at the given zero-relative index.
 void addModifyListener ( ModifyListener listener)
          Adds the listener to the collection of listeners who will be notified when the receiver's text is modified, by sending it one of the messages defined in the ModifyListener interface.
 void addSelectionListener ( SelectionListener listener)
          Adds the listener to the collection of listeners who will be notified when the receiver's selection changes, by sending it one of the messages defined in the SelectionListener interface.
 void addVerifyListener ( VerifyListener verifyListener)
          Adds the listener to the collection of listeners who will be notified when the receiver's text is verified, by sending it one of the messages defined in the VerifyListener interface.
 void clearSelection ()
           
  Point computeSize (int wHint, int hHint, boolean changed)
          Returns the preferred size of the receiver.
 void deselect (int index)
          Deselects the item at the given zero-relative index in the receiver's list.
 void deselectAll ()
          Deselects all selected items in the receiver's list.
  String getItem (int index)
          Returns the item at the given, zero-relative index in the receiver's list.
 int getItemCount ()
          Returns the number of items contained in the receiver's list.
  String[] getItems ()
          Returns a (possibly empty) array of Strings which are the items in the receiver's list.
 int getSelectionIndex ()
          Returns the zero-relative index of the item which is currently selected in the receiver's list, or -1 if no item is selected.
  String getText ()
          Returns a string containing a copy of the contents of the receiver's text field, or an empty string if there are no contents.
 int getVisibleItemCount ()
          Gets the number of items that are visible in the drop down portion of the receiver's list.
 int indexOf ( String string)
          Searches the receiver's list starting at the first item (index 0) until an item is found that is equal to the argument, and returns the index of that item.
 int indexOf ( String string, int start)
          Searches the receiver's list starting at the given, zero-relative index until an item is found that is equal to the argument, and returns the index of that item.
 void remove (int index)
          Removes the item from the receiver's list at the given zero-relative index.
 void remove (int start, int end)
          Removes the items from the receiver's list which are between the given zero-relative start and end indices (inclusive).
 void remove ( String string)
          Searches the receiver's list starting at the first item until an item is found that is equal to the argument, and removes that item from the list.
 void removeAll ()
          Removes all of the items from the receiver's list and clear the contents of receiver's text field.
 void removeModifyListener ( ModifyListener listener)
          Removes the listener from the collection of listeners who will be notified when the receiver's text is modified.
 void removeSelectionListener ( SelectionListener listener)
          Removes the listener from the collection of listeners who will be notified when the receiver's selection changes.
 void removeVerifyListener ( VerifyListener verifyListener)
          Removes the listener from the collection of listeners who will be notified when the control is verified.
 void select (int selectionIndex)
          Selects the item at the given zero-relative index in the receiver's list.
 void setItem (int index, String string)
          Sets the text of the item in the receiver's list at the given zero-relative index to the string argument.
 void setItems ( String[] items)
          Sets the receiver's list to be the given array of items.
 void setText ( String string)
          Sets the contents of the receiver's text field to the given string.
 void setVisibleItemCount (int count)
          Sets the number of items that are visible in the drop down portion of the receiver's list.
 
Methods inherited from class org.eclipse.swt.widgets. Composite
changed, getAdapter, getBackgroundMode, getChildren, getLayout, getLayoutDeferred, getTabList, isLayoutDeferred, layout, layout, layout, layout, setBackgroundMode, setFocus, setLayout, setTabList
 
Methods inherited from class org.eclipse.swt.widgets. Scrollable
computeTrim, getClientArea
 
Methods inherited from class org.eclipse.swt.widgets. Control
addControlListener, addFocusListener, addKeyListener, addMouseListener, addTraverseListener, computeSize, forceFocus, getBackground, getBackgroundImage, getBorderWidth, getBounds, getCursor, getEnabled, getFont, getForeground, getLayoutData, getLocation, getMenu, getMonitor, getParent, getShell, getSize, getToolTipText, getVisible, isEnabled, isFocusControl, isVisible, moveAbove, moveBelow, pack, pack, redraw, removeControlListener, removeFocusListener, removeKeyListener, removeMouseListener, removeTraverseListener, setBackground, setBackgroundImage, setBounds, setBounds, setCursor, setEnabled, setFont, setForeground, setLayoutData, setLocation, setLocation, setMenu, setRedraw, setSize, setSize, setToolTipText, setVisible, toControl, toControl, toDisplay, toDisplay
 
Methods inherited from class org.eclipse.swt.widgets. Widget
addDisposeListener, addListener, checkSubclass, checkWidget, dispose, getData, getData, getDisplay, getStyle, isDisposed, notifyListeners, removeDisposeListener, removeListener, setData, setData, toString
 
Methods inherited from class java.lang. Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Combo

public Combo(
Composite parent,
             int style)
Constructs a new instance of this class given its parent and a style value describing its behavior and appearance.

The style value is either one of the style constants defined in class SWT which is applicable to instances of this class, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those SWT style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses.

Parameters:
parent - a composite control which will be the parent of the new instance (cannot be null)
style - the style of control to construct
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the parent is null
SWTException -
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
  • ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass
See Also:
SWT.DROP_DOWN, SWT.READ_ONLY, SWT.SIMPLE, Widget.checkSubclass(), Widget.getStyle()
Method Detail

getSelectionIndex

public int getSelectionIndex()
Returns the zero-relative index of the item which is currently selected in the receiver's list, or -1 if no item is selected.

Returns:
the index of the selected item
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

select

public void select(int selectionIndex)
Selects the item at the given zero-relative index in the receiver's list. If the item at the index was already selected, it remains selected. Indices that are out of range are ignored.

Parameters:
selectionIndex - the index of the item to select
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

deselect

public void deselect(int index)
Deselects the item at the given zero-relative index in the receiver's list. If the item at the index was already deselected, it remains deselected. Indices that are out of range are ignored.

Parameters:
index - the index of the item to deselect
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

deselectAll

public void deselectAll()
Deselects all selected items in the receiver's list.

Note: To clear the selection in the receiver's text field, use clearSelection().

Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
clearSelection()

clearSelection

public void clearSelection()

add

public void add(
String string)
Adds the argument to the end of the receiver's list.

Parameters:
string - the new item
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the string is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
add(String,int)

add

public void add(
String string,
                int index)
Adds the argument to the receiver's list at the given zero-relative index.

Note: To add an item at the end of the list, use the result of calling getItemCount() as the index or use add(String).

Parameters:
string - the new item
index - the index for the item
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the string is null
  • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list (inclusive)
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
add(String)

remove

public void remove(int index)
Removes the item from the receiver's list at the given zero-relative index.

Parameters:
index - the index for the item
Throws:
IllegalArgumentException -
  • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

remove

public void remove(int start,
                   int end)
Removes the items from the receiver's list which are between the given zero-relative start and end indices (inclusive).

Parameters:
start - the start of the range
end - the end of the range
Throws:
IllegalArgumentException -
  • ERROR_INVALID_RANGE - if either the start or end are not between 0 and the number of elements in the list minus 1 (inclusive)
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

remove

public void remove(
String string)
Searches the receiver's list starting at the first item until an item is found that is equal to the argument, and removes that item from the list.

Parameters:
string - the item to remove
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the string is null
  • ERROR_INVALID_ARGUMENT - if the string is not found in the list
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

removeAll

public void removeAll()
Removes all of the items from the receiver's list and clear the contents of receiver's text field.

Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setItem

public void setItem(int index,
                    
String string)
Sets the text of the item in the receiver's list at the given zero-relative index to the string argument. This is equivalent to removing the old item at the index, and then adding the new item at that index.

Parameters:
index - the index for the item
string - the new text for the item
Throws:
IllegalArgumentException -
  • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)
  • ERROR_NULL_ARGUMENT - if the string is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setItems

public void setItems(
String[] items)
Sets the receiver's list to be the given array of items.

Parameters:
items - the array of items
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the items array is null
  • ERROR_INVALID_ARGUMENT - if an item in the items array is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getItem

public 
String getItem(int index)
Returns the item at the given, zero-relative index in the receiver's list. Throws an exception if the index is out of range.

Parameters:
index - the index of the item to return
Returns:
the item at the given index
Throws:
IllegalArgumentException -
  • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getItems

public 
String[] getItems()
Returns a (possibly empty) array of Strings which are the items in the receiver's list.

Note: This is not the actual structure used by the receiver to maintain its list of items, so modifying the array will not affect the receiver.

Returns:
the items in the receiver's list
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getItemCount

public int getItemCount()
Returns the number of items contained in the receiver's list.

Returns:
the number of items
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setVisibleItemCount

public void setVisibleItemCount(int count)
Sets the number of items that are visible in the drop down portion of the receiver's list.

Note: This operation is a hint and is not supported on platforms that do not have this concept.

Parameters:
count - the new number of items to be visible
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getVisibleItemCount

public int getVisibleItemCount()
Gets the number of items that are visible in the drop down portion of the receiver's list.

Note: This operation is a hint and is not supported on platforms that do not have this concept.

Returns:
the number of items that are visible
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

indexOf

public int indexOf(
String string)
Searches the receiver's list starting at the first item (index 0) until an item is found that is equal to the argument, and returns the index of that item. If no item is found, returns -1.

Parameters:
string - the search item
Returns:
the index of the item
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the string is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

indexOf

public int indexOf(
String string,
                   int start)
Searches the receiver's list starting at the given, zero-relative index until an item is found that is equal to the argument, and returns the index of that item. If no item is found or the starting index is out of range, returns -1.

Parameters:
string - the search item
start - the zero-relative index at which to begin the search
Returns:
the index of the item
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the string is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getText

public 
String getText()
Returns a string containing a copy of the contents of the receiver's text field, or an empty string if there are no contents.

Returns:
the receiver's text
Throws:
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setText

public void setText(
String string)
Sets the contents of the receiver's text field to the given string.

Note: The text field in a Combo is typically only capable of displaying a single line of text. Thus, setting the text to a string containing line breaks or other special characters will probably cause it to display incorrectly.

Parameters:
string - the new text
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the string is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

computeSize

public 
Point computeSize(int wHint,
                         int hHint,
                         boolean changed)
Description copied from class: Control
Returns the preferred size of the receiver.

The preferred size of a control is the size that it would best be displayed at. The width hint and height hint arguments allow the caller to ask a control questions such as "Given a particular width, how high does the control need to be to show all of the contents?" To indicate that the caller does not wish to constrain a particular dimension, the constant SWT.DEFAULT is passed for the hint.

If the changed flag is true, it indicates that the receiver's contents have changed, therefore any caches that a layout manager containing the control may have been keeping need to be flushed. When the control is resized, the changed flag will be false, so layout manager caches can be retained.

Overrides:
computeSize in class Composite

addSelectionListener

public void addSelectionListener(
SelectionListener listener)
Adds the listener to the collection of listeners who will be notified when the receiver's selection changes, by sending it one of the messages defined in the SelectionListener interface.

widgetSelected is called when the combo's list selection changes. widgetDefaultSelected is typically called when ENTER is pressed the combo's text area.

Parameters:
listener - the listener which should be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
SelectionListener, removeSelectionListener(org.eclipse.swt.events.SelectionListener), SelectionEvent

removeSelectionListener

public void removeSelectionListener(
SelectionListener listener)
Removes the listener from the collection of listeners who will be notified when the receiver's selection changes.

Parameters:
listener - the listener which should no longer be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
SelectionListener, addSelectionListener(org.eclipse.swt.events.SelectionListener)

addModifyListener

public void addModifyListener(
ModifyListener listener)
Adds the listener to the collection of listeners who will be notified when the receiver's text is modified, by sending it one of the messages defined in the ModifyListener interface.

Parameters:
listener - the listener which should be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
ModifyListener, removeModifyListener(org.eclipse.swt.events.ModifyListener)

removeModifyListener

public void removeModifyListener(
ModifyListener listener)
Removes the listener from the collection of listeners who will be notified when the receiver's text is modified.

Parameters:
listener - the listener which should no longer be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
ModifyListener, addModifyListener(org.eclipse.swt.events.ModifyListener)

addVerifyListener

public void addVerifyListener(
VerifyListener verifyListener)
Adds the listener to the collection of listeners who will be notified when the receiver's text is verified, by sending it one of the messages defined in the VerifyListener interface.

Parameters:
verifyListener - the listener which should be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
VerifyListener, removeVerifyListener(org.eclipse.swt.events.VerifyListener)

removeVerifyListener

public void removeVerifyListener(
VerifyListener verifyListener)
Removes the listener from the collection of listeners who will be notified when the control is verified.

Parameters:
verifyListener - the listener which should no longer be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
SWTException -
  • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
See Also:
VerifyListener, addVerifyListener(org.eclipse.swt.events.VerifyListener)

Eclipse Rich Ajax Platform
Release 1.2

Copyright (c) Innoopract Informationssysteme GmbH and others 2002, 2008. All rights reserved.


 
 
  Published under the terms of the Eclipse Public License Version 1.0 ("EPL") Design by Interspire