public class Combo extends Composite
Combo
s 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 Combo
s 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.
Note: Only one of the styles DROP_DOWN and SIMPLE may be specified.
IMPORTANT: This class is not intended to be subclassed.
Modifier and Type | Field and Description |
---|---|
static int |
LIMIT
the operating system limit for the number of characters
that the text field in an instance of this class can hold
|
Constructor and Description |
---|
Combo(Composite parent,
int style)
Constructs a new instance of this class given its parent
and a style value describing its behavior and appearance.
|
Modifier and Type | Method and Description |
---|---|
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 |
addSegmentListener(SegmentListener listener)
Adds a segment listener.
|
void |
addSelectionListener(SelectionListener listener)
Adds the listener to the collection of listeners who will
be notified when the user changes the receiver's selection, by sending
it one of the messages defined in the
SelectionListener
interface. |
void |
addVerifyListener(VerifyListener listener)
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. |
protected void |
checkSubclass()
Checks that this class can be subclassed.
|
void |
clearSelection()
Sets the selection in the receiver's text field to an empty
selection starting just before the first character.
|
void |
copy()
Copies the selected text.
|
void |
cut()
Cuts the selected text.
|
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.
|
Point |
getCaretLocation()
Returns a point describing the location of the caret relative
to the receiver.
|
int |
getCaretPosition()
Returns the character position of the caret.
|
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.
|
int |
getItemHeight()
Returns the height of the area which would be used to
display one of the items in the receiver's list.
|
String[] |
getItems()
Returns a (possibly empty) array of
String s which are
the items in the receiver's list. |
boolean |
getListVisible()
Returns
true if the receiver's list is visible,
and false otherwise. |
int |
getOrientation()
Returns the orientation of the receiver.
|
Point |
getSelection()
Returns a
Point whose x coordinate is the
character position representing the start of the selection
in the receiver's text field, and whose y coordinate is the
character position representing the end of the selection. |
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 |
getTextHeight()
Returns the height of the receivers's text field.
|
int |
getTextLimit()
Returns the maximum number of characters that the receiver's
text field is capable of holding.
|
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 |
paste()
Pastes text from clipboard.
|
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 |
removeSegmentListener(SegmentListener 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 user changes the receiver's selection.
|
void |
removeVerifyListener(VerifyListener listener)
Removes the listener from the collection of listeners who will
be notified when the control is verified.
|
void |
select(int index)
Selects the item at the given zero-relative index in the receiver's
list.
|
void |
setFont(Font font)
Sets the font that the receiver will use to paint textual information
to the font specified by the argument, or to the default font for that
kind of control if the argument is null.
|
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 |
setListVisible(boolean visible)
Marks the receiver's list as visible if the argument is
true ,
and marks it invisible otherwise. |
void |
setOrientation(int orientation)
Sets the orientation of the receiver, which must be one
of the constants
SWT.LEFT_TO_RIGHT or SWT.RIGHT_TO_LEFT . |
void |
setSelection(Point selection)
Sets the selection in the receiver's text field to the
range specified by the argument whose x coordinate is the
start of the selection and whose y coordinate is the end
of the selection.
|
void |
setText(String string)
Sets the contents of the receiver's text field to the
given string.
|
void |
setTextLimit(int limit)
Sets the maximum number of characters that the receiver's
text field is capable of holding to be the argument.
|
void |
setVisibleItemCount(int count)
Sets the number of items that are visible in the drop
down portion of the receiver's list.
|
changed, drawBackground, getBackgroundMode, getChildren, getLayout, getLayoutDeferred, getTabList, isLayoutDeferred, layout, layout, layout, layout, layout, setBackgroundMode, setFocus, setLayout, setLayoutDeferred, setTabList
computeTrim, getClientArea, getHorizontalBar, getScrollbarsMode, getVerticalBar
addControlListener, addDragDetectListener, addFocusListener, addGestureListener, addHelpListener, addKeyListener, addMenuDetectListener, addMouseListener, addMouseMoveListener, addMouseTrackListener, addMouseWheelListener, addPaintListener, addTouchListener, addTraverseListener, computeSize, computeSize, dragDetect, dragDetect, forceFocus, getAccessible, getBackground, getBackgroundImage, getBorderWidth, getBounds, getCursor, getDragDetect, getEnabled, getFont, getForeground, getLayoutData, getLocation, getMenu, getMonitor, getParent, getRegion, getShell, getSize, getTextDirection, getToolTipText, getTouchEnabled, getVisible, internal_dispose_GC, internal_new_GC, isAutoScalable, isEnabled, isFocusControl, isReparentable, isVisible, moveAbove, moveBelow, pack, pack, print, redraw, redraw, removeControlListener, removeDragDetectListener, removeFocusListener, removeGestureListener, removeHelpListener, removeKeyListener, removeMenuDetectListener, removeMouseListener, removeMouseMoveListener, removeMouseTrackListener, removeMouseWheelListener, removePaintListener, removeTouchListener, removeTraverseListener, requestLayout, setBackground, setBackgroundImage, setBounds, setBounds, setCapture, setCursor, setDragDetect, setEnabled, setForeground, setLayoutData, setLocation, setLocation, setMenu, setParent, setRedraw, setRegion, setSize, setSize, setTextDirection, setToolTipText, setTouchEnabled, setVisible, toControl, toControl, toDisplay, toDisplay, traverse, traverse, traverse, update
addDisposeListener, addListener, checkWidget, dispose, getData, getData, getDisplay, getListeners, getStyle, isAutoDirection, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, reskin, setData, setData, toString
public static final int LIMIT
public Combo(Composite parent, int style)
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.
parent
- a composite control which will be the parent of the new instance (cannot be null)style
- the style of control to constructIllegalArgumentException
- SWTException
- SWT.DROP_DOWN
,
SWT.READ_ONLY
,
SWT.SIMPLE
,
Widget.checkSubclass()
,
Widget.getStyle()
public void add(String string)
Note: If control characters like '\n', '\t' etc. are used in the string, then the behavior is platform dependent.
string
- the new itemIllegalArgumentException
- SWTException
- add(String,int)
public void add(String string, int 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)
.
Also note, if control characters like '\n', '\t' etc. are used in the string, then the behavior is platform dependent.
string
- the new itemindex
- the index for the itemIllegalArgumentException
- SWTException
- add(String)
public void addModifyListener(ModifyListener listener)
ModifyListener
interface.listener
- the listener which should be notifiedIllegalArgumentException
- SWTException
- ModifyListener
,
removeModifyListener(org.eclipse.swt.events.ModifyListener)
public void addSegmentListener(SegmentListener listener)
A SegmentEvent
is sent whenever text content is being modified or
a segment listener is added or removed. You can
customize the appearance of text by indicating certain characters to be inserted
at certain text offsets. This may be used for bidi purposes, e.g. when
adjacent segments of right-to-left text should not be reordered relative to
each other.
E.g., multiple Java string literals in a right-to-left language
should generally remain in logical order to each other, that is, the
way they are stored.
Warning: This API is currently only implemented on Windows.
SegmentEvent
s won't be sent on GTK and Cocoa.
listener
- the listener which should be notifiedIllegalArgumentException
- SWTException
- SegmentEvent
,
SegmentListener
,
removeSegmentListener(org.eclipse.swt.events.SegmentListener)
public void addSelectionListener(SelectionListener listener)
SelectionListener
interface.
widgetSelected
is called when the user changes the combo's list selection.
widgetDefaultSelected
is typically called when ENTER is pressed the combo's text area.
listener
- the listener which should be notifiedIllegalArgumentException
- SWTException
- SelectionListener
,
removeSelectionListener(org.eclipse.swt.events.SelectionListener)
,
SelectionEvent
public void addVerifyListener(VerifyListener listener)
VerifyListener
interface.listener
- the listener which should be notifiedIllegalArgumentException
- SWTException
- VerifyListener
,
removeVerifyListener(org.eclipse.swt.events.VerifyListener)
protected void checkSubclass()
Widget
The SWT class library is intended to be subclassed
only at specific, controlled points (most notably,
Composite
and Canvas
when
implementing new widgets). This method enforces this
rule unless it is overridden.
IMPORTANT: By providing an implementation of this method that allows a subclass of a class which does not normally allow subclassing to be created, the implementer agrees to be fully responsible for the fact that any such subclass will likely fail between SWT releases and will be strongly platform specific. No support is provided for user-written classes which are implemented in this fashion.
The ability to subclass outside of the allowed SWT classes is intended purely to enable those not on the SWT development team to implement patches in order to get around specific limitations in advance of when those limitations can be addressed by the team. Subclassing should not be attempted without an intimate and detailed understanding of the hierarchy.
checkSubclass
in class Composite
public void clearSelection()
Note: To clear the selected items in the receiver's list,
use deselectAll()
.
SWTException
- deselectAll()
public void copy()
The current selection is copied to the clipboard.
SWTException
- public void cut()
The current selection is first copied to the clipboard and then deleted from the widget.
SWTException
- public void deselect(int index)
index
- the index of the item to deselectSWTException
- public void deselectAll()
Note: To clear the selection in the receiver's text field,
use clearSelection()
.
SWTException
- clearSelection()
public Point getCaretLocation()
SWTException
- public int getCaretPosition()
Indexing is zero based.
SWTException
- public String getItem(int index)
index
- the index of the item to returnIllegalArgumentException
- SWTException
- public int getItemCount()
SWTException
- public int getItemHeight()
SWTException
- public String[] getItems()
String
s 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.
SWTException
- public boolean getListVisible()
true
if the receiver's list is visible,
and false
otherwise.
If one of the receiver's ancestors is not visible or some other condition makes the receiver not visible, this method may still indicate that it is considered visible even though it may not actually be showing.
SWTException
- public void setListVisible(boolean visible)
true
,
and marks it invisible otherwise.
If one of the receiver's ancestors is not visible or some other condition makes the receiver not visible, marking it visible may not actually cause it to be displayed.
visible
- the new visibility stateSWTException
- public int getOrientation()
getOrientation
in class Control
SWTException
- public Point getSelection()
Point
whose x coordinate is the
character position representing the start of the selection
in the receiver's text field, and whose y coordinate is the
character position representing the end of the selection.
An "empty" selection is indicated by the x and y coordinates
having the same value.
Indexing is zero based. The range of a selection is from 0..N where N is the number of characters in the widget.
SWTException
- public int getSelectionIndex()
SWTException
- public String getText()
SWTException
- public int getTextHeight()
SWTException
- public int getTextLimit()
setTextLimit()
, it will be the constant
Combo.LIMIT
.SWTException
- LIMIT
public int getVisibleItemCount()
Note: This operation is a hint and is not supported on platforms that do not have this concept.
SWTException
- public int indexOf(String string)
string
- the search itemIllegalArgumentException
- SWTException
- public int indexOf(String string, int start)
string
- the search itemstart
- the zero-relative index at which to begin the searchIllegalArgumentException
- SWTException
- public void paste()
The selected text is deleted from the widget and new text inserted from the clipboard.
SWTException
- public void remove(int index)
index
- the index for the itemIllegalArgumentException
- SWTException
- public void remove(int start, int end)
start
- the start of the rangeend
- the end of the rangeIllegalArgumentException
- SWTException
- public void remove(String string)
string
- the item to removeIllegalArgumentException
- SWTException
- public void removeAll()
SWTException
- public void removeModifyListener(ModifyListener listener)
listener
- the listener which should no longer be notifiedIllegalArgumentException
- SWTException
- ModifyListener
,
addModifyListener(org.eclipse.swt.events.ModifyListener)
public void removeSegmentListener(SegmentListener listener)
listener
- the listener which should no longer be notifiedIllegalArgumentException
- SWTException
- SegmentEvent
,
SegmentListener
,
addSegmentListener(org.eclipse.swt.events.SegmentListener)
public void removeSelectionListener(SelectionListener listener)
listener
- the listener which should no longer be notifiedIllegalArgumentException
- SWTException
- SelectionListener
,
addSelectionListener(org.eclipse.swt.events.SelectionListener)
public void removeVerifyListener(VerifyListener listener)
listener
- the listener which should no longer be notifiedIllegalArgumentException
- SWTException
- VerifyListener
,
addVerifyListener(org.eclipse.swt.events.VerifyListener)
public void select(int index)
index
- the index of the item to selectSWTException
- public void setFont(Font font)
Control
public void setItem(int index, String string)
index
- the index for the itemstring
- the new text for the itemIllegalArgumentException
- SWTException
- public void setItems(String... items)
items
- the array of itemsIllegalArgumentException
- SWTException
- public void setOrientation(int orientation)
SWT.LEFT_TO_RIGHT
or SWT.RIGHT_TO_LEFT
.
setOrientation
in class Control
orientation
- new orientation styleSWTException
- public void setSelection(Point selection)
selection
- a point representing the new selection start and endIllegalArgumentException
- SWTException
- public void setText(String string)
This call is ignored when the receiver is read only and the given string is not in the receiver's list.
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.
Also note, if control characters like '\n', '\t' etc. are used in the string, then the behavior is platform dependent.
string
- the new textIllegalArgumentException
- SWTException
- public void setTextLimit(int limit)
To reset this value to the default, use setTextLimit(Combo.LIMIT)
.
Specifying a limit value larger than Combo.LIMIT
sets the
receiver's limit to Combo.LIMIT
.
limit
- new text limitIllegalArgumentException
- SWTException
- LIMIT
public void setVisibleItemCount(int count)
Note: This operation is a hint and is not supported on platforms that do not have this concept.
count
- the new number of items to be visibleSWTException
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