Eclipse Platform
Release 4.2

org.eclipse.swt.widgets
Class Item

java.lang.Object
  extended by org.eclipse.swt.widgets.Widget
      extended by org.eclipse.swt.widgets.Item
Direct Known Subclasses:
CoolItem, CTabItem, ExpandItem, MenuItem, TabItem, TableColumn, TableItem, TableTreeItem, TaskItem, ToolItem, TrayItem, TreeColumn, TreeItem

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.

Styles:
(none)
Events:
(none)

See Also:
Sample code and further information

Constructor Summary
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.
 
Method Summary
protected  void checkSubclass()
          Checks that this class can be subclassed.
 Image getImage()
          Returns the receiver's image if it has one, or null if it does not.
 String getText()
          Returns the receiver's text, which will be an empty string if it has never been set.
 void setImage(Image image)
          Sets the receiver's image to the argument, which may be null indicating that no image should be displayed.
 void setText(String string)
          Sets the receiver's text.
 
Methods inherited from class org.eclipse.swt.widgets.Widget
addDisposeListener, addListener, checkWidget, dispose, getData, getData, getDisplay, getListeners, getStyle, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, reskin, setData, setData, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

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
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
See Also:
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
Throws:
IllegalArgumentException -
  • 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)
SWTException -
  • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
See Also:
SWT, Widget.getStyle()
Method Detail

checkSubclass

protected void checkSubclass()
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.

Overrides:
checkSubclass in class Widget

getImage

public Image getImage()
Returns the receiver's image if it has one, or null if it does not.

Returns:
the receiver's image
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

getText

public String getText()
Returns the receiver's text, which will be an empty string if it has never been set.

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

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)
Throws:
IllegalArgumentException -
  • ERROR_INVALID_ARGUMENT - if the image has been disposed
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 receiver's text.

Parameters:
string - the new text
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the text 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

Eclipse Platform
Release 4.2

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