org.eclipse.swt.widgets

Class Label

java.lang.Object

org.eclipse.swt.widgets.Widget

org.eclipse.swt.widgets.Control

org.eclipse.swt.widgets.Label

All Implemented Interfaces:

Drawable

public class Label
extends Control

Instances of this class represent a non-selectable user interface object that displays a string or image. When SEPARATOR is specified, displays a single vertical or horizontal line.

Shadow styles are hints and may not be honored by the platform. To create a separator label with the default shadow style for the platform, do not specify a shadow style.

Styles:

SEPARATOR, HORIZONTAL, VERTICAL

SHADOW_IN, SHADOW_OUT, SHADOW_NONE

CENTER, LEFT, RIGHT, WRAP

Events:

(none)

Note: Only one of SHADOW_IN, SHADOW_OUT and SHADOW_NONE may be specified. SHADOW_NONE is a HINT. Only one of HORIZONTAL and VERTICAL may be specified. Only one of CENTER, LEFT and RIGHT may be specified.

IMPORTANT: This class is not intended to be subclassed.

See Also:

Label snippets, SWT Example: ControlExample, Sample code and further information

Structure Diagram

Field Summary

Fields

Modifier and Type	Field and Description
(package private) Image	image
(package private) static boolean	IMAGE_AND_TEXT
(package private) static TCHAR	LabelClass
(package private) static int	LabelProc
(package private) static int	MARGIN
(package private) java.lang.String	text

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

accessible, background, backgroundImage, cursor, drawCount, font, foreground, handle, layoutData, menu, parent, region, toolTipText

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

CANVAS, data, DEFAULT_HEIGHT, DEFAULT_WIDTH, DISABLED, display, DISPOSE_SENT, DISPOSED, DRAG_DETECT, DRAW_BACKGROUND, eventTable, FOREIGN_HANDLE, HIDDEN, IGNORE_WM_CHANGEUISTATE, KEYED_DATA, LAYOUT_CHANGED, LAYOUT_CHILD, LAYOUT_NEEDED, MAJOR, MINOR, MOVE_DEFERRED, MOVE_OCCURRED, PARENT_BACKGROUND, RELEASED, RESIZE_DEFERRED, RESIZE_OCCURRED, SKIN_NEEDED, state, style, THEME_BACKGROUND, TRACK_MOUSE

Constructor Summary

Constructors

Constructor and Description
Label(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

Methods

Modifier and Type	Method and Description
(package private) int	callWindowProc(int hwnd, int msg, int wParam, int lParam)
(package private) static int	checkStyle(int style)
Point	computeSize(int wHint, int hHint, boolean changed) Returns the preferred size of the receiver.
(package private) void	createHandle()
int	getAlignment() Returns a value which describes the position of the text or image in the receiver.
Image	getImage() Returns the receiver's image if it has one, or null if it does not.
(package private) java.lang.String	getNameText()
java.lang.String	getText() Returns the receiver's text, which will be an empty string if it has never been set or if the receiver is a SEPARATOR label.
(package private) boolean	mnemonicHit(char key)
(package private) boolean	mnemonicMatch(char key)
(package private) void	releaseWidget()
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	setText(java.lang.String string) Sets the receiver's text.
(package private) int	widgetExtStyle()
(package private) int	widgetStyle()
(package private) TCHAR	windowClass()
(package private) int	windowProc()
(package private) LRESULT	WM_ERASEBKGND(int wParam, int lParam)
(package private) LRESULT	WM_PAINT(int wParam, int lParam)
(package private) LRESULT	WM_SIZE(int wParam, int lParam)
(package private) LRESULT	WM_UPDATEUISTATE(int wParam, int lParam)
(package private) LRESULT	wmColorChild(int wParam, int lParam)
(package private) LRESULT	wmDrawChild(int wParam, int lParam)

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

addControlListener, addDragDetectListener, addFocusListener, addGestureListener, addHelpListener, addKeyListener, addMenuDetectListener, addMouseListener, addMouseMoveListener, addMouseTrackListener, addMouseWheelListener, addPaintListener, addTouchListener, addTraverseListener, binarySearch, borderHandle, checkBackground, checkBorder, checkBuffered, checkComposited, checkGesture, checkHandle, checkMirrored, computeSize, computeTabGroup, computeTabList, computeTabRoot, createWidget, defaultBackground, defaultFont, defaultForeground, deregister, destroyWidget, dragDetect, dragDetect, dragDetect, drawBackground, drawBackground, drawBackground, drawImageBackground, drawThemeBackground, enableDrag, enableWidget, fillBackground, fillImageBackground, fillThemeBackground, findBackgroundControl, findBrush, findCursor, findImageControl, findMenus, findMnemonic, findThemeControl, fixChildren, fixFocus, forceFocus, forceResize, getAccessible, getBackground, getBackgroundImage, getBackgroundPixel, getBorderWidth, getBounds, getClipboardText, getCodePage, getCursor, getDragDetect, getDrawing, getEnabled, getFont, getForeground, getForegroundPixel, getLayoutData, getLocation, getMenu, getMonitor, getOrientation, getParent, getPath, getRegion, getShell, getSize, getToolTipText, getTouchEnabled, getVisible, hasCursor, hasFocus, internal_dispose_GC, internal_new_GC, isActive, isEnabled, isFocusAncestor, isFocusControl, isReparentable, isShowing, isTabGroup, isTabItem, isVisible, mapEvent, markLayout, menuShell, moveAbove, moveBelow, new_Accessible, new_GC, pack, pack, print, printWidget, redraw, redraw, redraw, redrawChildren, register, releaseHandle, releaseParent, removeControlListener, removeDragDetectListener, removeFocusListener, removeGestureListener, removeHelpListener, removeKeyListener, removeMenuDetectListener, removeMouseListener, removeMouseMoveListener, removeMouseTrackListener, removeMouseWheelListener, removePaintListener, removeTouchListener, removeTraverseListener, sendFocusEvent, sendGestureEvent, sendMove, sendResize, sendTouchEvent, setBackground, setBackground, setBackgroundImage, setBackgroundImage, setBackgroundPixel, setBounds, setBounds, setBounds, setBounds, setCapture, setCursor, setCursor, setDefaultFont, setDragDetect, setEnabled, setFocus, setFont, setForeground, setForegroundPixel, setLayoutData, setLocation, setLocation, setMenu, setOrientation, setParent, setRadioFocus, setRadioSelection, setRedraw, setRegion, setSavedFocus, setSize, setSize, setTabItemFocus, setToolTipText, setToolTipText, setTouchEnabled, setVisible, showWidget, sort, subclass, toControl, toControl, toDisplay, toDisplay, topHandle, translateAccelerator, translateMnemonic, translateMnemonic, translateTraversal, traverse, traverse, traverse, traverse, traverse, traverseEscape, traverseGroup, traverseItem, traverseMnemonic, traversePage, traverseReturn, unsubclass, update, update, updateBackgroundColor, updateBackgroundImage, updateBackgroundMode, updateFont, updateImages, updateLayout, updateOrientation, widgetCreateStruct, widgetParent, windowProc, WM_ACTIVATE, WM_CAPTURECHANGED, WM_CHANGEUISTATE, WM_CHAR, WM_CLEAR, WM_CLOSE, WM_COMMAND, WM_CONTEXTMENU, WM_CTLCOLOR, WM_CUT, WM_DESTROY, WM_DRAWITEM, WM_ENDSESSION, WM_ENTERIDLE, WM_GESTURE, WM_GETDLGCODE, WM_GETFONT, WM_GETMINMAXINFO, WM_GETOBJECT, WM_HELP, WM_HOTKEY, WM_HSCROLL, WM_IME_CHAR, WM_IME_COMPOSITION_START, WM_IME_COMPOSITION, WM_IME_ENDCOMPOSITION, WM_INITMENUPOPUP, WM_INPUTLANGCHANGE, WM_KEYDOWN, WM_KEYUP, WM_KILLFOCUS, WM_LBUTTONDBLCLK, WM_LBUTTONDOWN, WM_LBUTTONUP, WM_MBUTTONDBLCLK, WM_MBUTTONDOWN, WM_MBUTTONUP, WM_MEASUREITEM, WM_MENUCHAR, WM_MENUSELECT, WM_MOUSEACTIVATE, WM_MOUSEHOVER, WM_MOUSEHWHEEL, WM_MOUSELEAVE, WM_MOUSEMOVE, WM_MOUSEWHEEL, WM_MOVE, WM_NCACTIVATE, WM_NCCALCSIZE, WM_NCHITTEST, WM_NCLBUTTONDOWN, WM_NCPAINT, WM_NOTIFY, WM_PALETTECHANGED, WM_PARENTNOTIFY, WM_PASTE, WM_PRINT, WM_PRINTCLIENT, WM_QUERYENDSESSION, WM_QUERYNEWPALETTE, WM_QUERYOPEN, WM_RBUTTONDBLCLK, WM_RBUTTONDOWN, WM_RBUTTONUP, WM_SETCURSOR, WM_SETFOCUS, WM_SETFONT, WM_SETREDRAW, WM_SETTINGCHANGE, WM_SHOWWINDOW, WM_SYSCHAR, WM_SYSCOLORCHANGE, WM_SYSCOMMAND, WM_SYSKEYDOWN, WM_SYSKEYUP, WM_TABLET_FLICK, WM_TIMER, WM_TOUCH, WM_UNDO, WM_UNINITMENUPOPUP, WM_VSCROLL, WM_WINDOWPOSCHANGED, WM_WINDOWPOSCHANGING, WM_XBUTTONDBLCLK, WM_XBUTTONDOWN, WM_XBUTTONUP, wmCommandChild, wmMeasureChild, wmNotify, wmNotifyChild, wmScrollChild

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

_addListener, addDisposeListener, addListener, checkBits, checkOpened, checkOrientation, checkParent, checkSubclass, checkWidget, DeferWindowPos, dispose, dragDetect, error, filters, findItem, fixMnemonic, fixMnemonic, getData, getData, getDisplay, getListeners, getName, getStyle, hooks, isDisposed, isListening, isValidSubclass, isValidThread, notifyListeners, postEvent, postEvent, release, releaseChildren, removeDisposeListener, removeListener, removeListener, reskin, reskinChildren, reskinWidget, sendDragEvent, sendDragEvent, sendEvent, sendEvent, sendEvent, sendEvent, sendKeyEvent, sendKeyEvent, sendMouseEvent, sendMouseEvent, sendMouseWheelEvent, sendSelectionEvent, sendSelectionEvent, setData, setData, setInputState, setKeyState, setLocationMask, setTabGroupFocus, SetWindowPos, showMenu, showMenu, toString, updateMenuLocation, wmCaptureChanged, wmChar, wmContextMenu, wmIMEChar, wmKeyDown, wmKeyUp, wmKillFocus, wmLButtonDblClk, wmLButtonDown, wmLButtonUp, wmMButtonDblClk, wmMButtonDown, wmMButtonUp, wmMouseHover, wmMouseHWheel, wmMouseLeave, wmMouseMove, wmMouseWheel, wmNCPaint, wmPaint, wmPrint, wmRButtonDblClk, wmRButtonDown, wmRButtonUp, wmSetFocus, wmSysChar, wmSysKeyDown, wmSysKeyUp, wmXButtonDblClk, wmXButtonDown, wmXButtonUp

Methods inherited from class java.lang.Object

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

Field Detail

text

java.lang.String text

image

Image image

MARGIN

static final int MARGIN

See Also:

Constant Field Values

IMAGE_AND_TEXT

static boolean IMAGE_AND_TEXT

LabelProc

static final int LabelProc

LabelClass

static final TCHAR LabelClass

Constructor Detail

Label

public Label(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:

java.lang.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.SEPARATOR, SWT.HORIZONTAL, SWT.VERTICAL, SWT.SHADOW_IN, SWT.SHADOW_OUT, SWT.SHADOW_NONE, SWT.CENTER, SWT.LEFT, SWT.RIGHT, SWT.WRAP, Widget.checkSubclass(), Widget.getStyle()

Method Detail

callWindowProc

int callWindowProc(int hwnd,
                 int msg,
                 int wParam,
                 int lParam)

Overrides:

callWindowProc in class Widget

checkStyle

static int checkStyle(int style)

computeSize

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

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.

Overrides:

computeSize in class Control

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.

See Also:

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

createHandle

void createHandle()

Overrides:

createHandle in class Control

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 unless the receiver is a SEPARATOR label, in which case, NONE is returned.

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

getImage

public Image getImage()

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

Returns:

the receiver's 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

getNameText

java.lang.String getNameText()

Overrides:

getNameText in class Widget

getText

public java.lang.String getText()

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

Returns:

the receiver's 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

mnemonicHit

boolean mnemonicHit(char key)

Overrides:

mnemonicHit in class Control

mnemonicMatch

boolean mnemonicMatch(char key)

Overrides:

mnemonicMatch in class Control

releaseWidget

void releaseWidget()

Overrides:

releaseWidget in class Control

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. If the receiver is a SEPARATOR label, the argument is ignored and the alignment is not changed.

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)

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

Parameters:

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

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the image 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

setText

public void setText(java.lang.String string)

Sets the receiver's text.

This method sets the widget label. The label may include the mnemonic character and line delimiters.

Mnemonics are indicated by an '&' that causes the next character to be the mnemonic. When the user presses a key sequence that matches the mnemonic, focus is assigned to the control that follows the label. On most platforms, the mnemonic appears underlined but may be emphasised in a platform specific manner. The mnemonic indicator character '&' can be escaped by doubling it in the string, causing a single '&' to be displayed.

Parameters:

string - the new text

Throws:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the text 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

widgetExtStyle

int widgetExtStyle()

Overrides:

widgetExtStyle in class Control

widgetStyle

int widgetStyle()

Overrides:

widgetStyle in class Control

windowClass

TCHAR windowClass()

Specified by:

windowClass in class Control

windowProc

int windowProc()

Specified by:

windowProc in class Control

WM_ERASEBKGND

LRESULT WM_ERASEBKGND(int wParam,
                    int lParam)

Overrides:

WM_ERASEBKGND in class Control

WM_SIZE

LRESULT WM_SIZE(int wParam,
              int lParam)

Overrides:

WM_SIZE in class Control

WM_UPDATEUISTATE

LRESULT WM_UPDATEUISTATE(int wParam,
                       int lParam)

Overrides:

WM_UPDATEUISTATE in class Control

wmColorChild

LRESULT wmColorChild(int wParam,
                   int lParam)

Overrides:

wmColorChild in class Control

WM_PAINT

LRESULT WM_PAINT(int wParam,
               int lParam)

Overrides:

WM_PAINT in class Control

wmDrawChild

LRESULT wmDrawChild(int wParam,
                  int lParam)

Overrides:

wmDrawChild in class Control