Package org.eclipse.swt.widgets

Class TreeColumn

java.lang.Object

org.eclipse.swt.widgets.Widget

org.eclipse.swt.widgets.Item

org.eclipse.swt.widgets.TreeColumn

public class TreeColumn
extends Item

Instances of this class represent a column in a tree widget.

Styles:

LEFT, RIGHT, CENTER

Events:

Move, Resize, Selection

Note: Only one of the styles LEFT, RIGHT and CENTER may be specified.

IMPORTANT: This class is not intended to be subclassed.

Since:

3.1

See Also:

• Tree, TreeItem, TreeColumn snippets
• Sample code and further information

Restriction:

This class is not intended to be subclassed by clients.

Field Summary

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

nativeZoom

Constructor Summary

Constructors

Constructor	Description
TreeColumn(Tree parent, int style)	Constructs a new instance of this class given its parent (which must be a Tree) and a style value describing its behavior and appearance.
TreeColumn(Tree parent, int style, int index)	Constructs a new instance of this class given its parent (which must be a Tree), a style value describing its behavior and appearance, and the index at which to place it in the items maintained by its parent.

Method Summary

Modifier and Type	Method	Description
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	addSelectionListener(SelectionListener listener)	Adds the listener to the collection of listeners who will be notified when the control is selected by the user, by sending it one of the messages defined in the SelectionListener interface.
protected void	checkSubclass()	Checks that this class can be subclassed.
int	getAlignment()	Returns a value which describes the position of the text or image in the receiver.
boolean	getMoveable()	Gets the moveable attribute.
Tree	getParent()	Returns the receiver's parent, which must be a Tree.
boolean	getResizable()	Gets the resizable attribute.
String	getToolTipText()	Returns the receiver's tool tip text, or null if it has not been set.
int	getWidth()	Gets the width of the receiver.
void	pack()	Causes the receiver to be resized to its preferred size.
void	removeControlListener(ControlListener listener)	Removes the listener from the collection of listeners who will be notified when the control is moved or resized.
void	removeSelectionListener(SelectionListener listener)	Removes the listener from the collection of listeners who will be notified when the control is selected by the user.
void	setAlignment(int alignment)	Controls how text and images will be displayed in the receiver.
void	setImage(Image image)	Sets the receiver's image to the argument, which may be null indicating that no image should be displayed.
void	setMoveable(boolean moveable)	Sets the moveable attribute.
void	setResizable(boolean resizable)	Sets the resizable attribute.
void	setText(String string)	Sets the receiver's text.
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	setWidth(int width)	Sets the width of the receiver.

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

getImage, getText

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

addDisposeListener, addListener, addTypedListener, checkWidget, dispose, getData, getData, getDisplay, getListeners, getStyle, getTypedListeners, isAutoDirection, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, removeTypedListener, reskin, setData, setData, toString

Methods inherited from class java.lang.Object

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

Constructor Details

TreeColumn

public TreeColumn(Tree parent,
 int style)

Constructs a new instance of this class given its parent (which must be a Tree) and a style value describing its behavior and appearance. The item is added to the end of the items maintained by its parent.

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

Parameters:

parent - a 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

See Also:

• SWT.LEFT
• SWT.RIGHT
• SWT.CENTER
• Widget.checkSubclass()
• Widget.getStyle()

TreeColumn

public TreeColumn(Tree parent,
 int style,
 int index)

Constructs a new instance of this class given its parent (which must be a Tree), a style value describing its behavior and appearance, and the index at which to place it in the items maintained by its parent.

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

Note that due to a restriction on some platforms, the first column is always left aligned.

Parameters:

parent - a composite control which will be the parent of the new instance (cannot be null)

style - the style of control to construct

index - the zero-relative index to store the receiver in its parent

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the parent is null
• ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the parent (inclusive)

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
• ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass

See Also:

• SWT.LEFT
• SWT.RIGHT
• SWT.CENTER
• Widget.checkSubclass()
• Widget.getStyle()

Method Details

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

See Also:

• ControlListener
• removeControlListener(org.eclipse.swt.events.ControlListener)

addSelectionListener

public void addSelectionListener(SelectionListener listener)

Adds the listener to the collection of listeners who will be notified when the control is selected by the user, by sending it one of the messages defined in the SelectionListener interface.

widgetSelected is called when the column header is selected. widgetDefaultSelected is not called.

Parameters:

listener - the listener which should be notified when the control is selected by the user

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

See Also:

• SelectionListener
• removeSelectionListener(org.eclipse.swt.events.SelectionListener)
• SelectionEvent

checkSubclass

protected void checkSubclass()

Description copied from class: Widget

Checks that this class can be subclassed.

The SWT class library is intended to be subclassed only at specific, controlled points (most notably, Composite and Canvas when implementing new widgets). This method enforces this rule unless it is overridden.

IMPORTANT: By providing an implementation of this method that allows a subclass of a class which does not normally allow subclassing to be created, the implementer agrees to be fully responsible for the fact that any such subclass will likely fail between SWT releases and will be strongly platform specific. No support is provided for user-written classes which are implemented in this fashion.

The ability to subclass outside of the allowed SWT classes is intended purely to enable those not on the SWT development team to implement patches in order to get around specific limitations in advance of when those limitations can be addressed by the team. Subclassing should not be attempted without an intimate and detailed understanding of the hierarchy.

Overrides:

checkSubclass in class Item

getAlignment

public int getAlignment()

Returns a value which describes the position of the text or image in the receiver. The value will be one of LEFT, RIGHT or CENTER.

Returns:

the alignment

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

getMoveable

public boolean getMoveable()

Gets the moveable attribute. A column that is not moveable cannot be reordered by the user by dragging the header but may be reordered by the programmer.

Returns:

the moveable attribute

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

See Also:

• Tree.getColumnOrder()
• Tree.setColumnOrder(int[])
• setMoveable(boolean)
• SWT.Move

getParent

public Tree getParent()

Returns the receiver's parent, which must be a Tree.

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

getResizable

public boolean getResizable()

Gets the resizable attribute. A column that is not resizable cannot be dragged by the user but may be resized by the programmer.

Returns:

the resizable attribute

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

Since:

3.2

getWidth

public int getWidth()

Gets the width of the receiver.

Returns:

the 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

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

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

See Also:

• ControlListener
• addControlListener(org.eclipse.swt.events.ControlListener)

removeSelectionListener

public void removeSelectionListener(SelectionListener listener)

Removes the listener from the collection of listeners who will be notified when the control is selected by the user.

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

See Also:

• SelectionListener
• addSelectionListener(org.eclipse.swt.events.SelectionListener)

setAlignment

public void setAlignment(int alignment)

Controls how text and images will be displayed in the receiver. The argument should be one of LEFT, RIGHT or CENTER.

Note that due to a restriction on some platforms, the first column is always left aligned.

Parameters:

alignment - the new alignment

Throws:

SWTException -

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

setImage

public void setImage(Image image)

Description copied from class: Item

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

Overrides:

setImage in class Item

Parameters:

image - the image to display on the receiver (may be null)

setMoveable

public void setMoveable(boolean moveable)

Sets the moveable attribute. A column that is moveable can be reordered by the user by dragging the header. A column that is not moveable cannot be dragged by the user but may be reordered by the programmer.

Parameters:

moveable - the moveable attribute

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

See Also:

• Tree.setColumnOrder(int[])
• Tree.getColumnOrder()
• getMoveable()
• SWT.Move

setResizable

public void setResizable(boolean resizable)

Sets the resizable attribute. A column that is not resizable cannot be dragged by the user but may be resized by the programmer.

Parameters:

resizable - the resize attribute

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

setText

public void setText(String string)

Description copied from class: Item

Sets the receiver's text.

Note: If control characters like '\n', '\t' etc. are used in the string, then the behavior is platform dependent.

Overrides:

setText in class Item

Parameters:

string - the new text

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.

NOTE: This operation is a hint and behavior is platform specific, on Windows for CJK-style mnemonics of the form " (&C)" at the end of the tooltip text are not shown in tooltip.

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

Since:

3.2

setWidth

public void setWidth(int width)

Sets the width of the receiver.

Parameters:

width - the new 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