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org.eclipse.swt.widgets
Class Slider
java.lang.Object
org.eclipse.swt.widgets.Widget
org.eclipse.swt.widgets.Control
org.eclipse.swt.widgets.Slider
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All Implemented Interfaces:
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Drawable
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public class Slider
- extends
Control
Instances of this class are selectable user interface
objects that represent a range of positive, numeric values.
At any given moment, a given slider will have a
single 'selection' that is considered to be its
value, which is constrained to be within the range of
values the slider represents (that is, between its
minimum and maximum values).
Typically, sliders will be made up of five areas:
- an arrow button for decrementing the value
- a page decrement area for decrementing the value by a larger amount
- a thumb for modifying the value by mouse dragging
- a page increment area for incrementing the value by a larger amount
- an arrow button for incrementing the value
Based on their style, sliders are either HORIZONTAL
(which have a left facing button for decrementing the value and a
right facing button for incrementing it) or VERTICAL
(which have an upward facing button for decrementing the value
and a downward facing buttons for incrementing it).
On some platforms, the size of the slider's thumb can be
varied relative to the magnitude of the range of values it
represents (that is, relative to the difference between its
maximum and minimum values). Typically, this is used to
indicate some proportional value such as the ratio of the
visible area of a document to the total amount of space that
it would take to display it. SWT supports setting the thumb
size even if the underlying platform does not, but in this
case the appearance of the slider will not change.
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Styles:
- HORIZONTAL, VERTICAL
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Events:
- Selection
Note: Only one of the styles HORIZONTAL and VERTICAL may be specified.
IMPORTANT: This class is not intended to be subclassed.
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See Also:
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ScrollBar ,
Slider snippets,
SWT Example: ControlExample,
Sample code and further information
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Restriction:
- This class is not intended to be subclassed by clients.
Fields inherited from class org.eclipse.swt.widgets.
Control
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handle
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Constructor Summary
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Slider
(
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
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void
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addSelectionListener
(
SelectionListener listener)
Adds the listener to the collection of listeners who will
be notified when the user changes the receiver's value, by sending
it one of the messages defined in the SelectionListener
interface. |
Point
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computeSize
(int wHint,
int hHint,
boolean changed)
Returns the preferred size of the receiver. |
boolean
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getEnabled
()
Returns true if the receiver is enabled, and
false otherwise. |
int
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getIncrement
()
Returns the amount that the receiver's value will be
modified by when the up/down (or right/left) arrows
are pressed. |
int
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getMaximum
()
Returns the maximum value which the receiver will allow. |
int
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getMinimum
()
Returns the minimum value which the receiver will allow. |
int
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getPageIncrement
()
Returns the amount that the receiver's value will be
modified by when the page increment/decrement areas
are selected. |
int
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getSelection
()
Returns the 'selection', which is the receiver's value. |
int
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getThumb
()
Returns the size of the receiver's thumb relative to the
difference between its maximum and minimum values. |
void
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removeSelectionListener
(
SelectionListener listener)
Removes the listener from the collection of listeners who will
be notified when the user changes the receiver's value. |
void
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setIncrement
(int value)
Sets the amount that the receiver's value will be
modified by when the up/down (or right/left) arrows
are pressed to the argument, which must be at least
one. |
void
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setMaximum
(int value)
Sets the maximum. |
void
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setMinimum
(int value)
Sets the minimum value. |
void
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setPageIncrement
(int value)
Sets the amount that the receiver's value will be
modified by when the page increment/decrement areas
are selected to the argument, which must be at least
one. |
void
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setSelection
(int value)
Sets the 'selection', which is the receiver's
value, to the argument which must be greater than or equal
to zero. |
void
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setThumb
(int value)
Sets the size of the receiver's thumb relative to the
difference between its maximum and minimum values. |
void
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setValues
(int selection,
int minimum,
int maximum,
int thumb,
int increment,
int pageIncrement)
Sets the receiver's selection, minimum value, maximum
value, thumb, increment and page increment all at once. |
Methods inherited from class org.eclipse.swt.widgets.
Control
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addControlListener,
addDragDetectListener,
addFocusListener,
addHelpListener,
addKeyListener,
addMenuDetectListener,
addMouseListener,
addMouseMoveListener,
addMouseTrackListener,
addMouseWheelListener,
addPaintListener,
addTraverseListener,
computeSize,
dragDetect,
dragDetect,
forceFocus,
getAccessible,
getBackground,
getBackgroundImage,
getBorderWidth,
getBounds,
getCursor,
getDragDetect,
getFont,
getForeground,
getLayoutData,
getLocation,
getMenu,
getMonitor,
getParent,
getRegion,
getShell,
getSize,
getToolTipText,
getVisible,
internal_dispose_GC,
internal_new_GC,
isEnabled,
isFocusControl,
isReparentable,
isVisible,
moveAbove,
moveBelow,
pack,
pack,
print,
redraw,
redraw,
removeControlListener,
removeDragDetectListener,
removeFocusListener,
removeHelpListener,
removeKeyListener,
removeMenuDetectListener,
removeMouseListener,
removeMouseMoveListener,
removeMouseTrackListener,
removeMouseWheelListener,
removePaintListener,
removeTraverseListener,
setBackground,
setBackgroundImage,
setBounds,
setBounds,
setCapture,
setCursor,
setDragDetect,
setEnabled,
setFocus,
setFont,
setForeground,
setLayoutData,
setLocation,
setLocation,
setMenu,
setParent,
setRedraw,
setRegion,
setSize,
setSize,
setToolTipText,
setVisible,
toControl,
toControl,
toDisplay,
toDisplay,
traverse,
update
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Methods inherited from class org.eclipse.swt.widgets.
Widget
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addDisposeListener,
addListener,
checkSubclass,
checkWidget,
dispose,
getData,
getData,
getDisplay,
getListeners,
getStyle,
isDisposed,
isListening,
notifyListeners,
removeDisposeListener,
removeListener,
removeListener,
setData,
setData,
toString
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Slider
public Slider(
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.
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Parameters:
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parent - a composite control which will be the parent of the new instance (cannot be null) -
style - the style of control to construct
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the parent is null
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SWTException
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- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
- ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass
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See Also:
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SWT.HORIZONTAL ,
SWT.VERTICAL ,
Widget.checkSubclass() ,
Widget.getStyle()
addSelectionListener
public void addSelectionListener(
SelectionListener listener)
- Adds the listener to the collection of listeners who will
be notified when the user changes the receiver's value, by sending
it one of the messages defined in the
SelectionListener
interface.
When widgetSelected is called, the event object detail field contains one of the following values:
SWT.NONE - for the end of a drag.
SWT.DRAG .
SWT.HOME .
SWT.END .
SWT.ARROW_DOWN .
SWT.ARROW_UP .
SWT.PAGE_DOWN .
SWT.PAGE_UP .
widgetDefaultSelected is not called.
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Parameters:
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listener - the listener which should be notified when the user changes the receiver's value
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the listener is null
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
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See Also:
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SelectionListener ,
removeSelectionListener(org.eclipse.swt.events.SelectionListener) ,
SelectionEvent
computeSize
public
Point computeSize(int wHint,
int hHint,
boolean changed)
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Description copied from class:
Control
- 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.
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.
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Overrides:
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computeSize
in class
Control
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Parameters:
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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
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Returns:
- the preferred size of the control.
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See Also:
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Layout ,
Control.getBorderWidth() ,
Control.getBounds() ,
Control.getSize() ,
Control.pack(boolean) ,
"computeTrim, getClientArea for controls that implement them"
getEnabled
public boolean getEnabled()
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Description copied from class:
Control
- 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.
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Overrides:
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getEnabled
in class
Control
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Returns:
- the receiver's enabled state
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See Also:
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Control.isEnabled()
getIncrement
public int getIncrement()
- Returns the amount that the receiver's value will be
modified by when the up/down (or right/left) arrows
are pressed.
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Returns:
- the increment
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
getMaximum
public int getMaximum()
- Returns the maximum value which the receiver will allow.
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Returns:
- the maximum
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
getMinimum
public int getMinimum()
- Returns the minimum value which the receiver will allow.
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Returns:
- the minimum
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
getPageIncrement
public int getPageIncrement()
- Returns the amount that the receiver's value will be
modified by when the page increment/decrement areas
are selected.
-
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Returns:
- the page increment
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
getSelection
public int getSelection()
- Returns the 'selection', which is the receiver's value.
-
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Returns:
- the selection
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
getThumb
public int getThumb()
- Returns the size of the receiver's thumb relative to the
difference between its maximum and minimum values.
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Returns:
- the thumb value
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
removeSelectionListener
public void removeSelectionListener(
SelectionListener listener)
- Removes the listener from the collection of listeners who will
be notified when the user changes the receiver's value.
-
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Parameters:
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listener - the listener which should no longer be notified
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the listener is null
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
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See Also:
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SelectionListener ,
addSelectionListener(org.eclipse.swt.events.SelectionListener)
setIncrement
public void setIncrement(int value)
- Sets the amount that the receiver's value will be
modified by when the up/down (or right/left) arrows
are pressed to the argument, which must be at least
one.
-
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Parameters:
-
value - the new increment (must be greater than zero)
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setMaximum
public void setMaximum(int value)
- Sets the maximum. If this value is negative or less than or
equal to the minimum, the value is ignored. If necessary, first
the thumb and then the selection are adjusted to fit within the
new range.
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Parameters:
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value - the new maximum, which must be greater than the current minimum
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setMinimum
public void setMinimum(int value)
- Sets the minimum value. If this value is negative or greater
than or equal to the maximum, the value is ignored. If necessary,
first the thumb and then the selection are adjusted to fit within
the new range.
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Parameters:
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value - the new minimum
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setPageIncrement
public void setPageIncrement(int value)
- Sets the amount that the receiver's value will be
modified by when the page increment/decrement areas
are selected to the argument, which must be at least
one.
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Parameters:
-
value - the page increment (must be greater than zero)
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setSelection
public void setSelection(int value)
- Sets the 'selection', which is the receiver's
value, to the argument which must be greater than or equal
to zero.
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Parameters:
-
value - the new selection (must be zero or greater)
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setThumb
public void setThumb(int value)
- Sets the size of the receiver's thumb relative to the
difference between its maximum and minimum values. This new
value will be ignored if it is less than one, and will be
clamped if it exceeds the receiver's current range.
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Parameters:
-
value - the new thumb value, which must be at least one and not
larger than the size of the current range
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setValues
public void setValues(int selection,
int minimum,
int maximum,
int thumb,
int increment,
int pageIncrement)
- Sets the receiver's selection, minimum value, maximum
value, thumb, increment and page increment all at once.
Note: This is similar to setting the values individually
using the appropriate methods, but may be implemented in a
more efficient fashion on some platforms.
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Parameters:
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selection - the new selection value -
minimum - the new minimum value -
maximum - the new maximum value -
thumb - the new thumb value -
increment - the new increment value -
pageIncrement - the new pageIncrement value
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
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Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
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