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Eclipse Rich Ajax Platform
Release 1.2

org.eclipse.swt.custom
Class ScrolledComposite


java.lang.Object
  extended by

org.eclipse.swt.widgets.Widget
      extended by

org.eclipse.swt.widgets.Control
          extended by

org.eclipse.swt.widgets.Scrollable
              extended by

org.eclipse.swt.widgets.Composite
                  extended by
org.eclipse.swt.custom.ScrolledComposite
All Implemented Interfaces:
Adaptable

public class ScrolledComposite
extends Composite

A ScrolledComposite provides scrollbars and will scroll its content when the user uses the scrollbars.

There are two ways to use the ScrolledComposite:

1) Set the size of the control that is being scrolled and the ScrolledComposite will show scrollbars when the contained control can not be fully seen. 2) The second way imitates the way a browser would work. Set the minimum size of the control and the ScrolledComposite will show scroll bars if the visible area is less than the minimum size of the control and it will expand the size of the control if the visible area is greater than the minimum size. This requires invoking both setMinWidth(), setMinHeight() and setExpandHorizontal(), setExpandVertical().

Styles:
H_SCROLL, V_SCROLL

Since:
1.0

Constructor Summary
ScrolledComposite ( 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 dispose ()
          Disposes of the operating system resources associated with the receiver and all its descendents.
 boolean getAlwaysShowScrollBars ()
          Returns the Always Show Scrollbars flag.
  Rectangle getClientArea ()
          Returns a rectangle which describes the area of the receiver which is capable of displaying data (that is, not covered by the "trimmings").
  Control getContent ()
          Get the content that is being scrolled.
 boolean getExpandHorizontal ()
          Returns true if the content control will be expanded to fill available horizontal space.
 boolean getExpandVertical ()
          Returns true if the content control will be expanded to fill available vertical space.
  ScrollBar getHorizontalBar ()
          Returns the receiver's horizontal scroll bar if it has one, and null if it does not.
 int getMinHeight ()
          Returns the minimum height of the content control.
 int getMinWidth ()
          Returns the minimum width of the content control.
  Point getOrigin ()
          Return the point in the content that currently appears in the top left corner of the scrolled composite.
  ScrollBar getVerticalBar ()
          Returns the receiver's vertical scroll bar if it has one, and null if it does not.
 void setAlwaysShowScrollBars (boolean show)
          Set the Always Show Scrollbars flag.
 void setContent ( Control content)
          Set the content that will be scrolled.
 void setExpandHorizontal (boolean expand)
          Configure the ScrolledComposite to resize the content object to be as wide as the ScrolledComposite when the width of the ScrolledComposite is greater than the minimum width specified in setMinWidth.
 void setExpandVertical (boolean expand)
          Configure the ScrolledComposite to resize the content object to be as tall as the ScrolledComposite when the height of the ScrolledComposite is greater than the minimum height specified in setMinHeight.
 void setLayout ( Layout layout)
          Sets the layout which is associated with the receiver to be the argument which may be null.
 void setMinHeight (int height)
          Specify the minimum height at which the ScrolledComposite will begin scrolling the content with the vertical scroll bar.
 void setMinSize (int width, int height)
          Specify the minimum width and height at which the ScrolledComposite will begin scrolling the content with the horizontal scroll bar.
 void setMinSize ( Point size)
          Specify the minimum width and height at which the ScrolledComposite will begin scrolling the content with the horizontal scroll bar.
 void setMinWidth (int width)
          Specify the minimum width at which the ScrolledComposite will begin scrolling the content with the horizontal scroll bar.
 void setOrigin (int left, int top)
          Scrolls the content so that the specified point in the content is in the top left corner.
 void setOrigin ( Point origin)
          Scrolls the content so that the specified point in the content is in the top left corner.
 
Methods inherited from class org.eclipse.swt.widgets. Composite
changed, computeSize, getAdapter, getBackgroundMode, getChildren, getLayout, getLayoutDeferred, getTabList, isLayoutDeferred, layout, layout, layout, layout, setBackgroundMode, setFocus, setTabList
 
Methods inherited from class org.eclipse.swt.widgets. Scrollable
computeTrim
 
Methods inherited from class org.eclipse.swt.widgets. Control
addControlListener, addFocusListener, addKeyListener, addMouseListener, addTraverseListener, computeSize, forceFocus, getBackground, getBackgroundImage, getBorderWidth, getBounds, getCursor, getEnabled, getFont, getForeground, getLayoutData, getLocation, getMenu, getMonitor, getParent, getShell, getSize, getToolTipText, getVisible, isEnabled, isFocusControl, isVisible, moveAbove, moveBelow, pack, pack, redraw, removeControlListener, removeFocusListener, removeKeyListener, removeMouseListener, removeTraverseListener, setBackground, setBackgroundImage, setBounds, setBounds, setCursor, setEnabled, setFont, setForeground, setLayoutData, setLocation, setLocation, setMenu, setRedraw, setSize, setSize, setToolTipText, setVisible, toControl, toControl, toDisplay, toDisplay
 
Methods inherited from class org.eclipse.swt.widgets. Widget
addDisposeListener, addListener, checkSubclass, checkWidget, getData, getData, getDisplay, getStyle, isDisposed, notifyListeners, removeDisposeListener, removeListener, setData, setData, toString
 
Methods inherited from class java.lang. Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

ScrolledComposite

public ScrolledComposite(
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 widget which will be the parent of the new instance (cannot be null)
style - the style of widget 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.H_SCROLL, SWT.V_SCROLL, Widget.getStyle()
Method Detail

setLayout

public void setLayout(
Layout layout)
Sets the layout which is associated with the receiver to be the argument which may be null.

Note: No Layout can be set on this Control because it already manages the size and position of its children.

Overrides:
setLayout in class Composite
Parameters:
layout - the receiver's new layout 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

getClientArea

public 
Rectangle getClientArea()
Description copied from class: Scrollable
Returns a rectangle which describes the area of the receiver which is capable of displaying data (that is, not covered by the "trimmings").

Overrides:
getClientArea in class Scrollable
Returns:
the client area
See Also:
Scrollable.computeTrim(int, int, int, int)

setOrigin

public void setOrigin(
Point origin)
Scrolls the content so that the specified point in the content is in the top left corner. If no content has been set, nothing will occur. Negative values will be ignored. Values greater than the maximum scroll distance will result in scrolling to the end of the scrollbar.

Parameters:
origin - the point on the content to appear in the top left corner
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
  • ERROR_INVALID_ARGUMENT - value of origin is outside of content

setOrigin

public void setOrigin(int left,
                      int top)
Scrolls the content so that the specified point in the content is in the top left corner. If no content has been set, nothing will occur. Negative values will be ignored. Values greater than the maximum scroll distance will result in scrolling to the end of the scrollbar.

Parameters:
left - the x coordinate of the content to appear in the top left corner
top - the y coordinate of the content to appear in the top left corner
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

getOrigin

public 
Point getOrigin()
Return the point in the content that currently appears in the top left corner of the scrolled composite.

Returns:
the point in the content that currently appears in the top left corner of the scrolled composite. If no content has been set, this returns (0, 0).
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

setAlwaysShowScrollBars

public void setAlwaysShowScrollBars(boolean show)
Set the Always Show Scrollbars flag. True if the scrollbars are always shown even if they are not required. False if the scrollbars are only visible when some part of the composite needs to be scrolled to be seen. The H_SCROLL and V_SCROLL style bits are also required to enable scrollbars in the horizontal and vertical directions.

Parameters:
show - true to show the scrollbars even when not required, false to show scrollbars only when required
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

getAlwaysShowScrollBars

public boolean getAlwaysShowScrollBars()
Returns the Always Show Scrollbars flag. True if the scrollbars are always shown even if they are not required. False if the scrollbars are only visible when some part of the composite needs to be scrolled to be seen. The H_SCROLL and V_SCROLL style bits are also required to enable scrollbars in the horizontal and vertical directions.

Returns:
the Always Show Scrollbars flag value

getExpandHorizontal

public boolean getExpandHorizontal()
Returns true if the content control will be expanded to fill available horizontal space.

Returns:
the receiver's horizontal expansion 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

getExpandVertical

public boolean getExpandVertical()
Returns true if the content control will be expanded to fill available vertical space.

Returns:
the receiver's vertical expansion 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

setExpandHorizontal

public void setExpandHorizontal(boolean expand)
Configure the ScrolledComposite to resize the content object to be as wide as the ScrolledComposite when the width of the ScrolledComposite is greater than the minimum width specified in setMinWidth. If the ScrolledComposite is less than the minimum width, the content will not be resized and instead the horizontal scroll bar will be used to view the entire width. If expand is false, this behaviour is turned off. By default, this behaviour is turned off.

Parameters:
expand - true to expand the content control to fill available horizontal space
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

setExpandVertical

public void setExpandVertical(boolean expand)
Configure the ScrolledComposite to resize the content object to be as tall as the ScrolledComposite when the height of the ScrolledComposite is greater than the minimum height specified in setMinHeight. If the ScrolledComposite is less than the minimum height, the content will not be resized and instead the vertical scroll bar will be used to view the entire height. If expand is false, this behaviour is turned off. By default, this behaviour is turned off.

Parameters:
expand - true to expand the content control to fill available vertical space
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

getHorizontalBar

public 
ScrollBar getHorizontalBar()
Returns the receiver's horizontal scroll bar if it has one, and null if it does not.

Returns:
the horizontal scroll bar (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

getVerticalBar

public 
ScrollBar getVerticalBar()
Returns the receiver's vertical scroll bar if it has one, and null if it does not.

Returns:
the vertical scroll bar (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

setMinWidth

public void setMinWidth(int width)
Specify the minimum width at which the ScrolledComposite will begin scrolling the content with the horizontal scroll bar. This value is only relevant if setExpandHorizontal(true) has been set.

Parameters:
width - the minimum width or 0 for default 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

getMinWidth

public int getMinWidth()
Returns the minimum width of the content control.

Returns:
the minimum 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

setMinHeight

public void setMinHeight(int height)
Specify the minimum height at which the ScrolledComposite will begin scrolling the content with the vertical scroll bar. This value is only relevant if setExpandVertical(true) has been set.

Parameters:
height - the minimum height or 0 for default height
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

getMinHeight

public int getMinHeight()
Returns the minimum height of the content control.

Returns:
the minimum height
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

setMinSize

public void setMinSize(
Point size)
Specify the minimum width and height at which the ScrolledComposite will begin scrolling the content with the horizontal scroll bar. This value is only relevant if setExpandHorizontal(true) and setExpandVertical(true) have been set.

Parameters:
size - the minimum size or null for the default 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

setMinSize

public void setMinSize(int width,
                       int height)
Specify the minimum width and height at which the ScrolledComposite will begin scrolling the content with the horizontal scroll bar. This value is only relevant if setExpandHorizontal(true) and setExpandVertical(true) have been set.

Parameters:
width - the minimum width or 0 for default width
height - the minimum height or 0 for default height
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

setContent

public void setContent(
Control content)
Set the content that will be scrolled.

Parameters:
content - the control to be displayed in the content area
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

getContent

public 
Control getContent()
Get the content that is being scrolled.

Returns:
the control displayed in the content area

dispose

public void dispose()
Description copied from class: Widget
Disposes of the operating system resources associated with the receiver and all its descendents. After this method has been invoked, the receiver and all descendents will answer true when sent the message isDisposed(). Any internal connections between the widgets in the tree will have been removed to facilitate garbage collection.

NOTE: This method is not called recursively on the descendents 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 Dispose event.

Overrides:
dispose in class Widget
See Also:
Widget.addDisposeListener(org.eclipse.swt.events.DisposeListener), Widget.removeDisposeListener(org.eclipse.swt.events.DisposeListener), Widget.checkWidget()

Eclipse Rich Ajax Platform
Release 1.2

Copyright (c) Innoopract Informationssysteme GmbH and others 2002, 2008. All rights reserved.


 
 
  Published under the terms of the Eclipse Public License Version 1.0 ("EPL") Design by Interspire