Item

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. <dl> <dt><b>Styles:</b></dt> <dd>(none)</dd> <dt><b>Events:</b></dt> <dd>(none)</dd> </dl>

@see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>

Constructors

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

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

Members

Functions

getImage
Image getImage()

Returns the receiver's image if it has one, or null if it does not.

getText
String getText()

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

setImage
void setImage(Image image)

Sets the receiver's image to the argument, which may be null indicating that no image should be displayed.

setText
void setText(String string)

Sets the receiver's text.

Inherited Members

From Widget

handle
GtkWidget* handle;

the handle to the OS resource (Warning: This field is platform dependent) <p> <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT public API. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms and should never be accessed from application code. </p>

addListener
void addListener(int eventType, Listener listener)

Adds the listener to the collection of listeners who will be notified when an event of the given type occurs. When the event does occur in the widget, the listener is notified by sending it the <code>handleEvent()</code> message. The event type is one of the event constants defined in class <code>SWT</code>.

addDisposeListener
void addDisposeListener(DisposeListener listener)

Adds the listener to the collection of listeners who will be notified when the widget is disposed. When the widget is disposed, the listener is notified by sending it the <code>widgetDisposed()</code> message.

checkParent
void checkParent(Widget parent)

Throws an exception if the specified widget can not be used as a parent for the receiver.

checkSubclass
void checkSubclass()

Checks that this class can be subclassed. <p> The SWT class library is intended to be subclassed only at specific, controlled points (most notably, <code>Composite</code> and <code>Canvas</code> when implementing new widgets). This method enforces this rule unless it is overridden. </p><p> <em>IMPORTANT:</em> 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. </p><p> 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. </p>

checkWidget
void checkWidget()

Throws an <code>SWTException</code> if the receiver can not be accessed by the caller. This may include both checks on the state of the receiver and more generally on the entire execution context. This method <em>should</em> be called by widget implementors to enforce the standard SWT invariants. <p> Currently, it is an error to invoke any method (other than <code>isDisposed()</code>) on a widget that has had its <code>dispose()</code> method called. It is also an error to call widget methods from any thread that is different from the thread that created the widget. </p><p> In future releases of SWT, there may be more or fewer error checks and exceptions may be thrown for different reasons. </p>

dispose
void dispose()

Disposes of the operating system resources associated with the receiver and all its descendants. After this method has been invoked, the receiver and all descendants will answer <code>true</code> when sent the message <code>isDisposed()</code>. Any internal connections between the widgets in the tree will have been removed to facilitate garbage collection. <p> NOTE: This method is not called recursively on the descendants of the receiver. This means that, widget implementers can not detect when a widget is being disposed of by re-implementing this method, but should instead listen for the <code>Dispose</code> event. </p>

getData
Object getData()

Returns the application defined widget data associated with the receiver, or null if it has not been set. The <em>widget data</em> is a single, unnamed field that is stored with every widget. <p> Applications may put arbitrary objects in this field. If the object stored in the widget data needs to be notified when the widget is disposed of, it is the application's responsibility to hook the Dispose event on the widget and do so. </p>

getData
Object getData(String key)

Returns the application defined property of the receiver with the specified name, or null if it has not been set. <p> Applications may have associated arbitrary objects with the receiver in this fashion. If the objects stored in the properties need to be notified when the widget is disposed of, it is the application's responsibility to hook the Dispose event on the widget and do so. </p>

getDisplay
Display getDisplay()

Returns the <code>Display</code> that is associated with the receiver. <p> A widget's display is either provided when it is created (for example, top level <code>Shell</code>s) or is the same as its parent's display. </p>

getListeners
Listener[] getListeners(int eventType)

Returns an array of listeners who will be notified when an event of the given type occurs. The event type is one of the event constants defined in class <code>SWT</code>.

getStyle
int getStyle()

Returns the receiver's style information. <p> Note that the value which is returned by this method <em>may not match</em> the value which was provided to the constructor when the receiver was created. This can occur when the underlying operating system does not support a particular combination of requested styles. For example, if the platform widget used to implement a particular SWT widget always has scroll bars, the result of calling this method would always have the <code>SWT.H_SCROLL</code> and <code>SWT.V_SCROLL</code> bits set. </p>

isDisposed
bool isDisposed()

Returns <code>true</code> if the widget has been disposed, and <code>false</code> otherwise. <p> This method gets the dispose state for the widget. When a widget has been disposed, it is an error to invoke any other method using the widget. </p>

isListening
bool isListening(int eventType)

Returns <code>true</code> if there are any listeners for the specified event type associated with the receiver, and <code>false</code> otherwise. The event type is one of the event constants defined in class <code>SWT</code>.

notifyListeners
void notifyListeners(int eventType, Event event)

Notifies all of the receiver's listeners for events of the given type that one such event has occurred by invoking their <code>handleEvent()</code> method. The event type is one of the event constants defined in class <code>SWT</code>.

removeListener
void removeListener(int eventType, Listener handler)

Removes the listener from the collection of listeners who will be notified when an event of the given type occurs. The event type is one of the event constants defined in class <code>SWT</code>.

removeListener
void removeListener(int eventType, SWTEventListener handler)

Removes the listener from the collection of listeners who will be notified when an event of the given type occurs. <p> <b>IMPORTANT:</b> This method is <em>not</em> part of the SWT public API. It is marked public only so that it can be shared within the packages provided by SWT. It should never be referenced from application code. </p>

removeDisposeListener
void removeDisposeListener(DisposeListener listener)

Removes the listener from the collection of listeners who will be notified when the widget is disposed.

setData
void setData(Object data)

Sets the application defined widget data associated with the receiver to be the argument. The <em>widget data</em> is a single, unnamed field that is stored with every widget. <p> Applications may put arbitrary objects in this field. If the object stored in the widget data needs to be notified when the widget is disposed of, it is the application's responsibility to hook the Dispose event on the widget and do so. </p>

setData
void setData(String key, Object value)

Sets the application defined property of the receiver with the specified name to the given value. <p> Applications may associate arbitrary objects with the receiver in this fashion. If the objects stored in the properties need to be notified when the widget is disposed of, it is the application's responsibility to hook the Dispose event on the widget and do so. </p>

toString
String toString()

Returns a string containing a concise, human-readable description of the receiver.

Meta