Eclipse Plug-in Developer Guide (Galileo) - Control (Eclipse Platform API Specification)

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Eclipse Platform
Release 3.5

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org.eclipse.swt.widgets
Class Control


java.lang.Object
  

org.eclipse.swt.widgets.Widget
      
org.eclipse.swt.widgets.Control

All Implemented Interfaces:: Drawable

Direct Known Subclasses:: Button, Label, Link, ProgressBar, Sash, Scale, Scrollable, Slider

public abstract class Control
extends Widget
implements Drawable
extends Widget
implements Drawable

Control is the abstract superclass of all windowed user interface classes.

Styles:: BORDER; LEFT_TO_RIGHT, RIGHT_TO_LEFT
Events:: DragDetect, FocusIn, FocusOut, Help, KeyDown, KeyUp, MenuDetect, MouseDoubleClick, MouseDown, MouseEnter, MouseExit, MouseHover, MouseUp, MouseMove, Move, Paint, Resize, Traverse

Only one of LEFT_TO_RIGHT or RIGHT_TO_LEFT may be specified.

IMPORTANT: This class is intended to be subclassed only within the SWT implementation.

See Also:: Control snippets, SWT Example: ControlExample, Sample code and further information
Restriction:: This class is not intended to be subclassed by clients.

Field Summary

int handle
          the handle to the OS resource (Warning: This field is platform dependent) IMPORTANT: This field is not part of the SWT public API.

Constructor Summary

Control ( 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 addControlListener ( ControlListener listener)
          Adds the listener to the collection of listeners who will be notified when the control is moved or resized, by sending it one of the messages defined in the ControlListener interface.

void addDragDetectListener ( DragDetectListener listener)
          Adds the listener to the collection of listeners who will be notified when a drag gesture occurs, by sending it one of the messages defined in the DragDetectListener interface.

void addFocusListener ( FocusListener listener)
          Adds the listener to the collection of listeners who will be notified when the control gains or loses focus, by sending it one of the messages defined in the FocusListener interface.

void addHelpListener ( HelpListener listener)
          Adds the listener to the collection of listeners who will be notified when help events are generated for the control, by sending it one of the messages defined in the HelpListener interface.

void addKeyListener ( KeyListener listener)
          Adds the listener to the collection of listeners who will be notified when keys are pressed and released on the system keyboard, by sending it one of the messages defined in the KeyListener interface.

void addMenuDetectListener ( MenuDetectListener listener)
          Adds the listener to the collection of listeners who will be notified when the platform-specific context menu trigger has occurred, by sending it one of the messages defined in the MenuDetectListener interface.

void addMouseListener ( MouseListener listener)
          Adds the listener to the collection of listeners who will be notified when mouse buttons are pressed and released, by sending it one of the messages defined in the MouseListener interface.

void addMouseMoveListener ( MouseMoveListener listener)
          Adds the listener to the collection of listeners who will be notified when the mouse moves, by sending it one of the messages defined in the MouseMoveListener interface.

void addMouseTrackListener ( MouseTrackListener listener)
          Adds the listener to the collection of listeners who will be notified when the mouse passes or hovers over controls, by sending it one of the messages defined in the MouseTrackListener interface.

void addMouseWheelListener ( MouseWheelListener listener)
          Adds the listener to the collection of listeners who will be notified when the mouse wheel is scrolled, by sending it one of the messages defined in the MouseWheelListener interface.

void addPaintListener ( PaintListener listener)
          Adds the listener to the collection of listeners who will be notified when the receiver needs to be painted, by sending it one of the messages defined in the PaintListener interface.

void addTraverseListener ( TraverseListener listener)
          Adds the listener to the collection of listeners who will be notified when traversal events occur, by sending it one of the messages defined in the TraverseListener interface.

Point computeSize (int wHint, int hHint)
          Returns the preferred size of the receiver.

Point computeSize (int wHint, int hHint, boolean changed)
          Returns the preferred size of the receiver.

boolean dragDetect ( Event event)
          Detects a drag and drop gesture.

boolean dragDetect ( MouseEvent event)
          Detects a drag and drop gesture.

boolean forceFocus ()
          Forces the receiver to have the keyboard focus, causing all keyboard events to be delivered to it.

Accessible getAccessible ()
          Returns the accessible object for the receiver.

Color getBackground ()
          Returns the receiver's background color.

Image getBackgroundImage ()
          Returns the receiver's background image.

int getBorderWidth ()
          Returns the receiver's border width.

Rectangle getBounds ()
          Returns a rectangle describing the receiver's size and location relative to its parent (or its display if its parent is null), unless the receiver is a shell.

Cursor getCursor ()
          Returns the receiver's cursor, or null if it has not been set.

boolean getDragDetect ()
          Returns true if the receiver is detecting drag gestures, and false otherwise.

boolean getEnabled ()
          Returns true if the receiver is enabled, and false otherwise.

Font getFont ()
          Returns the font that the receiver will use to paint textual information.

Color getForeground ()
          Returns the foreground color that the receiver will use to draw.

Object getLayoutData ()
          Returns layout data which is associated with the receiver.

Point getLocation ()
          Returns a point describing the receiver's location relative to its parent (or its display if its parent is null), unless the receiver is a shell.

Menu getMenu ()
          Returns the receiver's pop up menu if it has one, or null if it does not.

Monitor getMonitor ()
          Returns the receiver's monitor.

Composite getParent ()
          Returns the receiver's parent, which must be a Composite or null when the receiver is a shell that was created with null or a display for a parent.

Region getRegion ()
          Returns the region that defines the shape of the control, or null if the control has the default shape.

Shell getShell ()
          Returns the receiver's shell.

Point getSize ()
          Returns a point describing the receiver's size.

String getToolTipText ()
          Returns the receiver's tool tip text, or null if it has not been set.

boolean getVisible ()
          Returns true if the receiver is visible, and false otherwise.

void internal_dispose_GC (int hDC, GCData data)
          Invokes platform specific functionality to dispose a GC handle.

int internal_new_GC ( GCData data)
          Invokes platform specific functionality to allocate a new GC handle.

boolean isEnabled ()
          Returns true if the receiver is enabled and all ancestors up to and including the receiver's nearest ancestor shell are enabled.

boolean isFocusControl ()
          Returns true if the receiver has the user-interface focus, and false otherwise.

boolean isReparentable ()
          Returns true if the underlying operating system supports this reparenting, otherwise false

boolean isVisible ()
          Returns true if the receiver is visible and all ancestors up to and including the receiver's nearest ancestor shell are visible.

void moveAbove ( Control control)
          Moves the receiver above the specified control in the drawing order.

void moveBelow ( Control control)
          Moves the receiver below the specified control in the drawing order.

void pack ()
          Causes the receiver to be resized to its preferred size.

void pack (boolean changed)
          Causes the receiver to be resized to its preferred size.

boolean print ( GC gc)
          Prints the receiver and all children.

void redraw ()
          Causes the entire bounds of the receiver to be marked as needing to be redrawn.

void redraw (int x, int y, int width, int height, boolean all)
          Causes the rectangular area of the receiver specified by the arguments to be marked as needing to be redrawn.

void removeControlListener ( ControlListener listener)
          Removes the listener from the collection of listeners who will be notified when the control is moved or resized.

void removeDragDetectListener ( DragDetectListener listener)
          Removes the listener from the collection of listeners who will be notified when a drag gesture occurs.

void removeFocusListener ( FocusListener listener)
          Removes the listener from the collection of listeners who will be notified when the control gains or loses focus.

void removeHelpListener ( HelpListener listener)
          Removes the listener from the collection of listeners who will be notified when the help events are generated for the control.

void removeKeyListener ( KeyListener listener)
          Removes the listener from the collection of listeners who will be notified when keys are pressed and released on the system keyboard.

void removeMenuDetectListener ( MenuDetectListener listener)
          Removes the listener from the collection of listeners who will be notified when the platform-specific context menu trigger has occurred.

void removeMouseListener ( MouseListener listener)
          Removes the listener from the collection of listeners who will be notified when mouse buttons are pressed and released.

void removeMouseMoveListener ( MouseMoveListener listener)
          Removes the listener from the collection of listeners who will be notified when the mouse moves.

void removeMouseTrackListener ( MouseTrackListener listener)
          Removes the listener from the collection of listeners who will be notified when the mouse passes or hovers over controls.

void removeMouseWheelListener ( MouseWheelListener listener)
          Removes the listener from the collection of listeners who will be notified when the mouse wheel is scrolled.

void removePaintListener ( PaintListener listener)
          Removes the listener from the collection of listeners who will be notified when the receiver needs to be painted.

void removeTraverseListener ( TraverseListener listener)
          Removes the listener from the collection of listeners who will be notified when traversal events occur.

void setBackground ( Color color)
          Sets the receiver's background color to the color specified by the argument, or to the default system color for the control if the argument is null.

void setBackgroundImage ( Image image)
          Sets the receiver's background image to the image specified by the argument, or to the default system color for the control if the argument is null.

void setBounds (int x, int y, int width, int height)
          Sets the receiver's size and location to the rectangular area specified by the arguments.

void setBounds ( Rectangle rect)
          Sets the receiver's size and location to the rectangular area specified by the argument.

void setCapture (boolean capture)
          If the argument is true, causes the receiver to have all mouse events delivered to it until the method is called with false as the argument.

void setCursor ( Cursor cursor)
          Sets the receiver's cursor to the cursor specified by the argument, or to the default cursor for that kind of control if the argument is null.

void setDragDetect (boolean dragDetect)
          Sets the receiver's drag detect state.

void setEnabled (boolean enabled)
          Enables the receiver if the argument is true, and disables it otherwise.

boolean setFocus ()
          Causes the receiver to have the keyboard focus, such that all keyboard events will be delivered to it.

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 setForeground ( Color color)
          Sets the receiver's foreground color to the color specified by the argument, or to the default system color for the control if the argument is null.

void setLayoutData ( Object layoutData)
          Sets the layout data associated with the receiver to the argument.

void setLocation (int x, int y)
          Sets the receiver's location to the point specified by the arguments which are relative to the receiver's parent (or its display if its parent is null), unless the receiver is a shell.

void setLocation ( Point location)
          Sets the receiver's location to the point specified by the arguments which are relative to the receiver's parent (or its display if its parent is null), unless the receiver is a shell.

void setMenu ( Menu menu)
          Sets the receiver's pop up menu to the argument.

boolean setParent ( Composite parent)
          Changes the parent of the widget to be the one provided if the underlying operating system supports this feature.

void setRedraw (boolean redraw)
          If the argument is false, causes subsequent drawing operations in the receiver to be ignored.

void setRegion ( Region region)
          Sets the shape of the control to the region specified by the argument.

void setSize (int width, int height)
          Sets the receiver's size to the point specified by the arguments.

void setSize ( Point size)
          Sets the receiver's size to the point specified by the argument.

void setToolTipText ( String string)
          Sets the receiver's tool tip text to the argument, which may be null indicating that the default tool tip for the control will be shown.

void setVisible (boolean visible)
          Marks the receiver as visible if the argument is true, and marks it invisible otherwise.

Point toControl (int x, int y)
          Returns a point which is the result of converting the argument, which is specified in display relative coordinates, to coordinates relative to the receiver.

Point toControl ( Point point)
          Returns a point which is the result of converting the argument, which is specified in display relative coordinates, to coordinates relative to the receiver.

Point toDisplay (int x, int y)
          Returns a point which is the result of converting the argument, which is specified in coordinates relative to the receiver, to display relative coordinates.

Point toDisplay ( Point point)
          Returns a point which is the result of converting the argument, which is specified in coordinates relative to the receiver, to display relative coordinates.

boolean traverse (int traversal)
          Based on the argument, perform one of the expected platform traversal action.

void update ()
          Forces all outstanding paint requests for the widget to be processed before this method returns.

Methods inherited from class org.eclipse.swt.widgets. Widget

addDisposeListener, addListener, checkSubclass, checkWidget, dispose, getData, getData, getDisplay, getListeners, getStyle, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, setData, setData, toString

Methods inherited from class java.lang. Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

handle

public int handle

the handle to the OS resource (Warning: This field is platform dependent)

IMPORTANT: This field is not 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.

Constructor Detail

Control

public Control(
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

Method Detail

addControlListener

public void addControlListener(
ControlListener listener)

Adds the listener to the collection of listeners who will be notified when the control is moved or resized, by sending it one of the messages defined in the ControlListener 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

addDragDetectListener

public void addDragDetectListener(
DragDetectListener listener)

Adds the listener to the collection of listeners who will be notified when a drag gesture occurs, by sending it one of the messages defined in the DragDetectListener 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

Since:

3.3

addFocusListener

public void addFocusListener(
FocusListener listener)

Adds the listener to the collection of listeners who will be notified when the control gains or loses focus, by sending it one of the messages defined in the FocusListener 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

addHelpListener

public void addHelpListener(
HelpListener listener)

Adds the listener to the collection of listeners who will be notified when help events are generated for the control, by sending it one of the messages defined in the HelpListener 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

addKeyListener

public void addKeyListener(
KeyListener listener)

Adds the listener to the collection of listeners who will be notified when keys are pressed and released on the system keyboard, by sending it one of the messages defined in the KeyListener interface.

When a key listener is added to a control, the control will take part in widget traversal. By default, all traversal keys (such as the tab key and so on) are delivered to the control. In order for a control to take part in traversal, it should listen for traversal events. Otherwise, the user can traverse into a control but not out. Note that native controls such as table and tree implement key traversal in the operating system. It is not necessary to add traversal listeners for these controls, unless you want to override the default traversal.

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

addMenuDetectListener

public void addMenuDetectListener(
MenuDetectListener listener)

Adds the listener to the collection of listeners who will be notified when the platform-specific context menu trigger has occurred, by sending it one of the messages defined in the MenuDetectListener 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

Since:

3.3

addMouseListener

public void addMouseListener(
MouseListener listener)

Adds the listener to the collection of listeners who will be notified when mouse buttons are pressed and released, by sending it one of the messages defined in the MouseListener 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

addMouseTrackListener

public void addMouseTrackListener(
MouseTrackListener listener)

Adds the listener to the collection of listeners who will be notified when the mouse passes or hovers over controls, by sending it one of the messages defined in the MouseTrackListener 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

addMouseMoveListener

public void addMouseMoveListener(
MouseMoveListener listener)

Adds the listener to the collection of listeners who will be notified when the mouse moves, by sending it one of the messages defined in the MouseMoveListener 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

addMouseWheelListener

public void addMouseWheelListener(
MouseWheelListener listener)

Adds the listener to the collection of listeners who will be notified when the mouse wheel is scrolled, by sending it one of the messages defined in the MouseWheelListener 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

Since:

3.3

addPaintListener

public void addPaintListener(
PaintListener listener)

Adds the listener to the collection of listeners who will be notified when the receiver needs to be painted, by sending it one of the messages defined in the PaintListener 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

addTraverseListener

public void addTraverseListener(
TraverseListener listener)

Adds the listener to the collection of listeners who will be notified when traversal events occur, by sending it one of the messages defined in the TraverseListener 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

computeSize

public 
Point computeSize(int wHint,
                         int hHint)

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.

Parameters:

wHint - the width hint (can be SWT.DEFAULT)

hHint - the height hint (can be SWT.DEFAULT)

Returns:

the preferred size of the control

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:

Layout, getBorderWidth(), getBounds(), getSize(), pack(boolean), "computeTrim, getClientArea for controls that implement them"

computeSize

public 
Point computeSize(int wHint,
                         int hHint,
                         boolean changed)

Returns the preferred size of the receiver.

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.

Parameters:

wHint - the width hint (can be SWT.DEFAULT)

hHint - the height hint (can be SWT.DEFAULT)

changed - true if the control's contents have changed, and false otherwise

Returns:

the preferred size of the control.

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:

Layout, getBorderWidth(), getBounds(), getSize(), pack(boolean), "computeTrim, getClientArea for controls that implement them"

dragDetect

public boolean dragDetect(
Event event)

Detects a drag and drop gesture. This method is used to detect a drag gesture when called from within a mouse down listener.

By default, a drag is detected when the gesture occurs anywhere within the client area of a control. Some controls, such as tables and trees, override this behavior. In addition to the operating system specific drag gesture, they require the mouse to be inside an item. Custom widget writers can use setDragDetect to disable the default detection, listen for mouse down, and then call dragDetect() from within the listener to conditionally detect a drag.

Parameters:

event - the mouse down event

Returns:

true if the gesture occurred, and false otherwise.

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT when the event 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

Since:

3.3

dragDetect

public boolean dragDetect(
MouseEvent event)

Detects a drag and drop gesture. This method is used to detect a drag gesture when called from within a mouse down listener.

Parameters:

event - the mouse down event

Returns:

true if the gesture occurred, and false otherwise.

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT when the event 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

Since:

3.3

forceFocus

public boolean forceFocus()

Forces the receiver to have the keyboard focus, causing all keyboard events to be delivered to it.

Returns:

true if the control got focus, and false if it was unable to.

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:

setFocus()

getAccessible

public 
Accessible getAccessible()

Returns the accessible object for the receiver. If this is the first time this object is requested, then the object is created and returned.

Returns:

the accessible object

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

Since:

2.0

getBackground

public 
Color getBackground()

Returns the receiver's background color.

Note: This operation is a hint and may be overridden by the platform. For example, on some versions of Windows the background of a TabFolder, is a gradient rather than a solid color.

Returns:

the background color

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

getBackgroundImage

public 
Image getBackgroundImage()

Returns the receiver's background image.

Returns:

the background 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

Since:

3.2

getBorderWidth

public int getBorderWidth()

Returns the receiver's border width.

Returns:

the border width

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

getBounds

public 
Rectangle getBounds()

Returns a rectangle describing the receiver's size and location relative to its parent (or its display if its parent is null), unless the receiver is a shell. In this case, the location is relative to the display.

Returns:

the receiver's bounding rectangle

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

getCursor

public 
Cursor getCursor()

Returns the receiver's cursor, or null if it has not been set.

When the mouse pointer passes over a control its appearance is changed to match the control's cursor.

Returns:

the receiver's cursor or null

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

Since:

3.3

getDragDetect

public boolean getDragDetect()

Returns true if the receiver is detecting drag gestures, and false otherwise.

Returns:

the receiver's drag detect state

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

Since:

3.3

getEnabled

public boolean getEnabled()

Returns true if the receiver is enabled, and false otherwise. A disabled control is typically not selectable from the user interface and draws with an inactive or "grayed" look.

Returns:

the receiver's enabled state

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:

isEnabled()

getFont

public 
Font getFont()

Returns the font that the receiver will use to paint textual information.

Returns:

the receiver's font

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

getForeground

public 
Color getForeground()

Returns the foreground color that the receiver will use to draw.

Returns:

the receiver's foreground color

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

getLayoutData

public 
Object getLayoutData()

Returns layout data which is associated with the receiver.

Returns:

the receiver's layout data

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

getLocation

public 
Point getLocation()

Returns a point describing the receiver's location relative to its parent (or its display if its parent is null), unless the receiver is a shell. In this case, the point is relative to the display.

Returns:

the receiver's location

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

getMenu

public 
Menu getMenu()

Returns the receiver's pop up menu if it has one, or null if it does not. All controls may optionally have a pop up menu that is displayed when the user requests one for the control. The sequence of key strokes, button presses and/or button releases that are used to request a pop up menu is platform specific.

Returns:

the receiver's menu

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

getMonitor

public 
Monitor getMonitor()

Returns the receiver's monitor.

Returns:: the receiver's monitor
Since:: 3.0

getParent

public 
Composite getParent()

Returns the receiver's parent, which must be a Composite or null when the receiver is a shell that was created with null or a display for a parent.

Returns:

the receiver's parent

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

getRegion

public 
Region getRegion()

Returns the region that defines the shape of the control, or null if the control has the default shape.

Returns:

the region that defines the shape of the shell (or null)

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

Since:

3.4

getShell

public 
Shell getShell()

Returns the receiver's shell. For all controls other than shells, this simply returns the control's nearest ancestor shell. Shells return themselves, even if they are children of other shells.

Returns:

the receiver's shell

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:

getParent()

getSize

public 
Point getSize()

Returns a point describing the receiver's size. The x coordinate of the result is the width of the receiver. The y coordinate of the result is the height of the receiver.

Returns:

the receiver's size

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

getToolTipText

public 
String getToolTipText()

Returns the receiver's tool tip text, or null if it has not been set.

Returns:

the receiver's tool tip 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

getVisible

public boolean getVisible()

Returns true if the receiver 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.

Returns:

the receiver's visibility state

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

internal_new_GC

public int internal_new_GC(
GCData data)

Invokes platform specific functionality to allocate a new GC handle.

IMPORTANT: This method is not part of the public API for Control. 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 called from application code.

Specified by:: internal_new_GC in interface Drawable

Parameters:: data - the platform specific GC data
Returns:: the platform specific GC handle

internal_dispose_GC

public void internal_dispose_GC(int hDC,
                                
GCData data)

Invokes platform specific functionality to dispose a GC handle.

Specified by:: internal_dispose_GC in interface Drawable

Parameters:: hDC - the platform specific GC handle; data - the platform specific GC data

isEnabled

public boolean isEnabled()

Returns true if the receiver is enabled and all ancestors up to and including the receiver's nearest ancestor shell are enabled. Otherwise, false is returned. A disabled control is typically not selectable from the user interface and draws with an inactive or "grayed" look.

Returns:

the receiver's enabled state

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:

getEnabled()

isFocusControl

public boolean isFocusControl()

Returns true if the receiver has the user-interface focus, and false otherwise.

Returns:

the receiver's focus state

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

isReparentable

public boolean isReparentable()

Returns true if the underlying operating system supports this reparenting, otherwise false

Returns:

true if the widget can be reparented, otherwise false

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

isVisible

public boolean isVisible()

Returns true if the receiver is visible and all ancestors up to and including the receiver's nearest ancestor shell are visible. Otherwise, false is returned.

Returns:

the receiver's visibility state

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:

getVisible()

moveAbove

public void moveAbove(
Control control)

Moves the receiver above the specified control in the drawing order. If the argument is null, then the receiver is moved to the top of the drawing order. The control at the top of the drawing order will not be covered by other controls even if they occupy intersecting areas.

Parameters:

control - the sibling control (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the control 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

moveBelow

public void moveBelow(
Control control)

Moves the receiver below the specified control in the drawing order. If the argument is null, then the receiver is moved to the bottom of the drawing order. The control at the bottom of the drawing order will be covered by all other controls which occupy intersecting areas.

Parameters:

control - the sibling control (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the control 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

pack

public void pack()

Causes the receiver to be resized to its preferred size. For a composite, this involves computing the preferred size from its layout, if there is one.

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:

computeSize(int, int, boolean)

pack

public void pack(boolean changed)

Causes the receiver to be resized to its preferred size. For a composite, this involves computing the preferred size from its layout, if there is one.

Parameters:

changed - whether or not the receiver's contents have changed

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:

computeSize(int, int, boolean)

print

public boolean print(
GC gc)

Prints the receiver and all children.

Parameters:

gc - the gc where the drawing occurs

Returns:

true if the operation was successful and false otherwise

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT - if the gc is null
ERROR_INVALID_ARGUMENT - if the gc 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

Since:

3.4

redraw

public void redraw()

Causes the entire bounds of the receiver to be marked as needing to be redrawn. The next time a paint request is processed, the control will be completely painted, including the background.

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

redraw

public void redraw(int x,
                   int y,
                   int width,
                   int height,
                   boolean all)

Causes the rectangular area of the receiver specified by the arguments to be marked as needing to be redrawn. The next time a paint request is processed, that area of the receiver will be painted, including the background. If the all flag is true, any children of the receiver which intersect with the specified area will also paint their intersecting areas. If the all flag is false, the children will not be painted.

Parameters:

x - the x coordinate of the area to draw

y - the y coordinate of the area to draw

width - the width of the area to draw

height - the height of the area to draw

all - true if children should redraw, and false otherwise

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

removeControlListener

public void removeControlListener(
ControlListener listener)

Removes the listener from the collection of listeners who will be notified when the control is moved or resized.

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

removeDragDetectListener

public void removeDragDetectListener(
DragDetectListener listener)

Removes the listener from the collection of listeners who will be notified when a drag gesture occurs.

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

Since:

3.3

removeFocusListener

public void removeFocusListener(
FocusListener listener)

Removes the listener from the collection of listeners who will be notified when the control gains or loses focus.

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

removeHelpListener

public void removeHelpListener(
HelpListener listener)

Removes the listener from the collection of listeners who will be notified when the help events are generated for the control.

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

removeKeyListener

public void removeKeyListener(
KeyListener listener)

Removes the listener from the collection of listeners who will be notified when keys are pressed and released on the system keyboard.

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

removeMenuDetectListener

public void removeMenuDetectListener(
MenuDetectListener listener)

Removes the listener from the collection of listeners who will be notified when the platform-specific context menu trigger has occurred.

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

Since:

3.3

removeMouseTrackListener

public void removeMouseTrackListener(
MouseTrackListener listener)

Removes the listener from the collection of listeners who will be notified when the mouse passes or hovers over controls.

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

removeMouseListener

public void removeMouseListener(
MouseListener listener)

Removes the listener from the collection of listeners who will be notified when mouse buttons are pressed and released.

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

removeMouseMoveListener

public void removeMouseMoveListener(
MouseMoveListener listener)

Removes the listener from the collection of listeners who will be notified when the mouse moves.

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

removeMouseWheelListener

public void removeMouseWheelListener(
MouseWheelListener listener)

Removes the listener from the collection of listeners who will be notified when the mouse wheel is scrolled.

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

Since:

3.3

removePaintListener

public void removePaintListener(
PaintListener listener)

Removes the listener from the collection of listeners who will be notified when the receiver needs to be painted.

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

removeTraverseListener

public void removeTraverseListener(
TraverseListener listener)

Removes the listener from the collection of listeners who will be notified when traversal events occur.

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

setBackground

public void setBackground(
Color color)

Sets the receiver's background color to the color specified by the argument, or to the default system color for the control if the argument is null.

Note: This operation is a hint and may be overridden by the platform. For example, on Windows the background of a Button cannot be changed.

Parameters:

color - the new color (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the argument 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

setBackgroundImage

public void setBackgroundImage(
Image image)

Sets the receiver's background image to the image specified by the argument, or to the default system color for the control if the argument is null. The background image is tiled to fill the available space.

Note: This operation is a hint and may be overridden by the platform. For example, on Windows the background of a Button cannot be changed.

Parameters:

image - the new image (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the argument has been disposed
ERROR_INVALID_ARGUMENT - if the argument is not a bitmap


SWTException

ERROR_WIDGET_DISPOSED - if the receiver has been disposed
ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

Since:

3.2

setBounds

public void setBounds(int x,
                      int y,
                      int width,
                      int height)

Sets the receiver's size and location to the rectangular area specified by the arguments. The x and y arguments are relative to the receiver's parent (or its display if its parent is null), unless the receiver is a shell. In this case, the x and y arguments are relative to the display.

Note: Attempting to set the width or height of the receiver to a negative number will cause that value to be set to zero instead.

Parameters:

x - the new x coordinate for the receiver

y - the new y coordinate for the receiver

width - the new width for the receiver

height - the new height for the receiver

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

setBounds

public void setBounds(
Rectangle rect)

Sets the receiver's size and location to the rectangular area specified by the argument. The x and y fields of the rectangle are relative to the receiver's parent (or its display if its parent is null).

Note: Attempting to set the width or height of the receiver to a negative number will cause that value to be set to zero instead.

Parameters:

rect - the new bounds for the receiver

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

setCapture

public void setCapture(boolean capture)

If the argument is true, causes the receiver to have all mouse events delivered to it until the method is called with false as the argument. Note that on some platforms, a mouse button must currently be down for capture to be assigned.

Parameters:

capture - true to capture the mouse, and false to release it

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

setCursor

public void setCursor(
Cursor cursor)

Sets the receiver's cursor to the cursor specified by the argument, or to the default cursor for that kind of control if the argument is null.

When the mouse pointer passes over a control its appearance is changed to match the control's cursor.

Parameters:

cursor - the new cursor (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the argument 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

setDragDetect

public void setDragDetect(boolean dragDetect)

Sets the receiver's drag detect state. If the argument is true, the receiver will detect drag gestures, otherwise these gestures will be ignored.

Parameters:

dragDetect - the new drag detect state

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

Since:

3.3

setEnabled

public void setEnabled(boolean enabled)

Enables the receiver if the argument is true, and disables it otherwise. A disabled control is typically not selectable from the user interface and draws with an inactive or "grayed" look.

Parameters:

enabled - the new enabled state

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

setFocus

public boolean setFocus()

Causes the receiver to have the keyboard focus, such that all keyboard events will be delivered to it. Focus reassignment will respect applicable platform constraints.

Returns:

true if the control got focus, and false if it was unable to.

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:

forceFocus()

setFont

public 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.

Parameters:

font - the new font (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the argument 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

setForeground

public void setForeground(
Color color)

Sets the receiver's foreground color to the color specified by the argument, or to the default system color for the control if the argument is null.

Note: This operation is a hint and may be overridden by the platform.

Parameters:

color - the new color (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the argument 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

setLayoutData

public void setLayoutData(
Object layoutData)

Sets the layout data associated with the receiver to the argument.

Parameters:

layoutData - the new layout data for the receiver.

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

setLocation

public void setLocation(int x,
                        int y)

Sets the receiver's location to the point specified by the arguments which are relative to the receiver's parent (or its display if its parent is null), unless the receiver is a shell. In this case, the point is relative to the display.

Parameters:

x - the new x coordinate for the receiver

y - the new y coordinate for the receiver

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

setLocation

public void setLocation(
Point location)

Parameters:

location - the new location for the receiver

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

setMenu

public void setMenu(
Menu menu)

Sets the receiver's pop up menu to the argument. All controls may optionally have a pop up menu that is displayed when the user requests one for the control. The sequence of key strokes, button presses and/or button releases that are used to request a pop up menu is platform specific.

Note: Disposing of a control that has a pop up menu will dispose of the menu. To avoid this behavior, set the menu to null before the control is disposed.

Parameters:

menu - the new pop up menu

Throws:


IllegalArgumentException

ERROR_MENU_NOT_POP_UP - the menu is not a pop up menu
ERROR_INVALID_PARENT - if the menu is not in the same widget tree
ERROR_INVALID_ARGUMENT - if the menu 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

setRedraw

public void setRedraw(boolean redraw)

If the argument is false, causes subsequent drawing operations in the receiver to be ignored. No drawing of any kind can occur in the receiver until the flag is set to true. Graphics operations that occurred while the flag was false are lost. When the flag is set to true, the entire widget is marked as needing to be redrawn. Nested calls to this method are stacked.

Note: This operation is a hint and may not be supported on some platforms or for some widgets.

Parameters:

redraw - the new redraw state

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

setRegion

public void setRegion(
Region region)

Sets the shape of the control to the region specified by the argument. When the argument is null, the default shape of the control is restored.

Parameters:

region - the region that defines the shape of the control (or null)

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the region 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

Since:

3.4

setSize

public void setSize(int width,
                    int height)

Sets the receiver's size to the point specified by the arguments.

Note: Attempting to set the width or height of the receiver to a negative number will cause that value to be set to zero instead.

Parameters:

width - the new width for the receiver

height - the new height for the receiver

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

setSize

public void setSize(
Point size)

Sets the receiver's size to the point specified by the argument.

Note: Attempting to set the width or height of the receiver to a negative number will cause them to be set to zero instead.

Parameters:

size - the new size for the receiver

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT - if the point 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

setToolTipText

public void setToolTipText(
String string)

Sets the receiver's tool tip text to the argument, which may be null indicating that the default tool tip for the control will be shown. For a control that has a default tool tip, such as the Tree control on Windows, setting the tool tip text to an empty string replaces the default, causing no tool tip text to be shown.

The mnemonic indicator (character '&') is not displayed in a tool tip. To display a single '&' in the tool tip, the character '&' can be escaped by doubling it in the string.

Parameters:

string - the new tool tip text (or null)

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

setVisible

public void setVisible(boolean visible)

Marks the receiver as visible if the argument is 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.

Parameters:

visible - the new visibility state

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

toControl

public 
Point toControl(int x,
                       int y)

Returns a point which is the result of converting the argument, which is specified in display relative coordinates, to coordinates relative to the receiver.

Parameters:

x - the x coordinate to be translated

y - the y coordinate to be translated

Returns:

the translated coordinates

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

Since:

2.1

toControl

public 
Point toControl(
Point point)

Returns a point which is the result of converting the argument, which is specified in display relative coordinates, to coordinates relative to the receiver.

Parameters:

point - the point to be translated (must not be null)

Returns:

the translated coordinates

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT - if the point 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

toDisplay

public 
Point toDisplay(int x,
                       int y)

Returns a point which is the result of converting the argument, which is specified in coordinates relative to the receiver, to display relative coordinates.

Parameters:

x - the x coordinate to be translated

y - the y coordinate to be translated

Returns:

the translated coordinates

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

Since:

2.1

toDisplay

public 
Point toDisplay(
Point point)

Returns a point which is the result of converting the argument, which is specified in coordinates relative to the receiver, to display relative coordinates.

Parameters:

point - the point to be translated (must not be null)

Returns:

the translated coordinates

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT - if the point 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

traverse

public boolean traverse(int traversal)

Based on the argument, perform one of the expected platform traversal action. The argument should be one of the constants: SWT.TRAVERSE_ESCAPE, SWT.TRAVERSE_RETURN, SWT.TRAVERSE_TAB_NEXT, SWT.TRAVERSE_TAB_PREVIOUS, SWT.TRAVERSE_ARROW_NEXT and SWT.TRAVERSE_ARROW_PREVIOUS.

Parameters:

traversal - the type of traversal

Returns:

true if the traversal succeeded

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

update

public void update()

Forces all outstanding paint requests for the widget to be processed before this method returns. If there are no outstanding paint request, this method does nothing.

Note: This method does not cause a redraw.

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

setParent

public boolean setParent(
Composite parent)

Changes the parent of the widget to be the one provided if the underlying operating system supports this feature. Returns true if the parent is successfully changed.

Parameters:

parent - the new parent for the control.

Returns:

true if the parent is changed and false otherwise.

Throws:


IllegalArgumentException

ERROR_INVALID_ARGUMENT - if the argument has been disposed
ERROR_NULL_ARGUMENT - if the parent 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

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Guidelines for using Eclipse APIs.

org.eclipse.swt.widgets Class Control

handle

Control

addControlListener

addDragDetectListener

addFocusListener

addHelpListener

addKeyListener

addMenuDetectListener

addMouseListener

addMouseTrackListener

addMouseMoveListener

addMouseWheelListener

addPaintListener

addTraverseListener

computeSize

computeSize

dragDetect

dragDetect

forceFocus

getAccessible

getBackground

getBackgroundImage

getBorderWidth

getBounds

getCursor

getDragDetect

getEnabled

getFont

getForeground

getLayoutData

getLocation

getMenu

getMonitor

getParent

getRegion

getShell

getSize

getToolTipText

getVisible

internal_new_GC

internal_dispose_GC

isEnabled

isFocusControl

isReparentable

isVisible

moveAbove

moveBelow

pack

pack

print

redraw

redraw

removeControlListener

removeDragDetectListener

removeFocusListener

removeHelpListener

removeKeyListener

removeMenuDetectListener

removeMouseTrackListener

removeMouseListener

removeMouseMoveListener

removeMouseWheelListener

removePaintListener

removeTraverseListener

setBackground

setBackgroundImage

setBounds

setBounds

setCapture

setCursor

setDragDetect

setEnabled

setFocus

setFont

setForeground

setLayoutData

setLocation

setLocation

setMenu

org.eclipse.swt.widgets
Class Control