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org.eclipse.swt.widgets
Class Item
java.lang.Object
org.eclipse.swt.widgets.Widget
org.eclipse.swt.widgets.Item
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Direct Known Subclasses:
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CoolItem,
CTabItem,
ExpandItem,
MenuItem,
TabItem,
TableColumn,
TableItem,
TableTreeItem,
ToolItem,
TrayItem,
TreeColumn,
TreeItem
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public abstract class Item
- extends
Widget
This class is the abstract superclass of all non-windowed
user interface objects that occur within specific controls.
For example, a tree will contain tree items.
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Styles:
- (none)
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Events:
- (none)
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See Also:
-
Sample code and further information
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Constructor Summary
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Item
(
Widget parent,
int style)
Constructs a new instance of this class given its parent
and a style value describing its behavior and appearance. |
Item
(
Widget parent,
int style,
int index)
Constructs a new instance of this class given its parent
and a style value describing its behavior and appearance,
and the index at which to place it in the items maintained
by its parent. |
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Method Summary
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protected void
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checkSubclass
()
Checks that this class can be subclassed. |
Image
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getImage
()
Returns the receiver's image if it has one, or null
if it does not. |
String
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getText
()
Returns the receiver's text, which will be an empty
string if it has never been set. |
void
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setImage
(
Image image)
Sets the receiver's image to the argument, which may be
null indicating that no image should be displayed. |
void
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setText
(
String string)
Sets the receiver's text. |
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Methods inherited from class org.eclipse.swt.widgets.
Widget
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addDisposeListener,
addListener,
checkWidget,
dispose,
getData,
getData,
getDisplay,
getListeners,
getStyle,
isDisposed,
isListening,
notifyListeners,
removeDisposeListener,
removeListener,
removeListener,
setData,
setData,
toString
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Item
public Item(
Widget parent,
int style)
- Constructs a new instance of this class given its parent
and a style value describing its behavior and appearance.
The item is added to the end of the items maintained by its parent.
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 widget which will be the parent of the new instance (cannot be null) -
style - the style of item to construct
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the parent is null
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SWTException
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- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
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See Also:
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SWT,
Widget.getStyle()
Item
public Item(
Widget parent,
int style,
int index)
- Constructs a new instance of this class given its parent
and a style value describing its behavior and appearance,
and the index at which to place it in the items maintained
by its parent.
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 widget which will be the parent of the new instance (cannot be null) -
style - the style of item to construct -
index - the zero-relative index at which to store the receiver in its parent
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the parent is null
- ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the parent (inclusive)
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SWTException
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- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
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See Also:
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SWT,
Widget.getStyle()
checkSubclass
protected void checkSubclass()
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Description copied from class:
Widget
- Checks that this class can be subclassed.
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.
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Overrides:
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checkSubclass
in class
Widget
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getImage
public
Image getImage()
- Returns the receiver's image if it has one, or null
if it does not.
-
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Returns:
- the receiver's image
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Throws:
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SWTException
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- 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 the receiver's text, which will be an empty
string if it has never been set.
-
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Returns:
- the receiver's text
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setImage
public void setImage(
Image image)
- Sets the receiver's image to the argument, which may be
null indicating that no image should be displayed.
-
-
Parameters:
-
image - the image to display on the receiver (may be null)
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Throws:
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IllegalArgumentException
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- ERROR_INVALID_ARGUMENT - if the image has been disposed
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SWTException
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- 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 receiver's text.
-
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Parameters:
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string - the new text
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the text is null
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
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