Class Button
- java.lang.Object
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- org.eclipse.swt.widgets.Widget
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- org.eclipse.swt.widgets.Control
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- org.eclipse.swt.widgets.Button
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public class Button extends Control
Instances of this class represent a selectable user interface object that issues notification when pressed and released.- Styles:
- CHECK, PUSH, RADIO, TOGGLE, FLAT, WRAP
- LEFT, RIGHT, CENTER
- Events:
- Selection
Note: Only one of the styles ARROW, CHECK, PUSH, RADIO, and TOGGLE may be specified.
Note: Only one of the styles LEFT, RIGHT, and CENTER may be specified.
Note: Only one of the styles UP, DOWN, LEFT, and RIGHT may be specified when the ARROW style is specified.
IMPORTANT: This class is intended to be subclassed only within the SWT implementation.
- Since:
- 1.0
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voidaddSelectionListener(SelectionListener listener)Adds the listener to the collection of listeners who will be notified when the control is selected, by sending it one of the messages defined in theSelectionListenerinterface.PointcomputeSize(int wHint, int hHint, boolean changed)Returns the preferred size of the receiver.<T> TgetAdapter(java.lang.Class<T> adapter)Implementation of theAdaptableinterface.intgetAlignment()Returns a value which describes the position of the text or image in the receiver.booleangetGrayed()Returnstrueif the receiver is grayed, and false otherwise.ImagegetImage()Returns the receiver's image if it has one, or null if it does not.booleangetSelection()Returnstrueif the receiver is selected, and false otherwise.java.lang.StringgetText()Returns the receiver's text, which will be an empty string if it has never been set.voidremoveSelectionListener(SelectionListener listener)Removes the listener from the collection of listeners who will be notified when the control is selected.voidsetAlignment(int alignment)Controls how text, images and arrows will be displayed in the receiver.voidsetData(java.lang.String key, java.lang.Object value)Sets the application defined property of the receiver with the specified name to the given value.voidsetGrayed(boolean grayed)Sets the grayed state of the receiver.voidsetImage(Image image)Sets the receiver's image to the argument, which may benullindicating that no image should be displayed.voidsetSelection(boolean selected)Sets the selection state of the receiver, if it is of typeCHECK,RADIO, orTOGGLE.voidsetText(java.lang.String text)Sets the receiver's text.-
Methods inherited from class org.eclipse.swt.widgets.Control
addControlListener, addDragDetectListener, addFocusListener, addGestureListener, addHelpListener, addKeyListener, addMenuDetectListener, addMouseListener, addTouchListener, addTraverseListener, computeSize, forceFocus, getAccessible, getBackground, getBackgroundImage, getBorderWidth, getBounds, getCursor, getEnabled, getFont, getForeground, getLayoutData, getLocation, getMenu, getMonitor, getOrientation, getParent, getShell, getSize, getToolTipText, getTouchEnabled, getVisible, isEnabled, isFocusControl, isReparentable, isVisible, moveAbove, moveBelow, pack, pack, redraw, redraw, removeControlListener, removeDragDetectListener, removeFocusListener, removeGestureListener, removeHelpListener, removeKeyListener, removeMenuDetectListener, removeMouseListener, removeTouchListener, removeTraverseListener, requestLayout, setBackground, setBackgroundImage, setBounds, setBounds, setCursor, setEnabled, setFocus, setFont, setForeground, setLayoutData, setLocation, setLocation, setMenu, setOrientation, setParent, setRedraw, setSize, setSize, setToolTipText, setTouchEnabled, setVisible, toControl, toControl, toDisplay, toDisplay, update
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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, reskin, setData, toString
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Constructor Detail
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Button
public Button(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
SWTwhich is applicable to instances of this class, or must be built by bitwise OR'ing together (that is, using theint"|" operator) two or more of thoseSWTstyle 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.CHECK,SWT.PUSH,SWT.RADIO,SWT.TOGGLE,SWT.FLAT,SWT.LEFT,SWT.RIGHT,SWT.CENTER,Widget.checkSubclass(),Widget.getStyle()
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Method Detail
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setText
public void setText(java.lang.String text)
Sets the receiver's text.This method sets the button label. The label may include the mnemonic character but must not contain 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, a selection event occurs. 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:
text- 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
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getText
public java.lang.String getText()
Returns the receiver's text, which will be an empty string if it has never been set.- 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
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getSelection
public boolean getSelection()
Returnstrueif the receiver is selected, and false otherwise.When the receiver is of type
CHECKorRADIO, it is selected when it is checked. When it is of typeTOGGLE, it is selected when it is pushed in. If the receiver is of any other type, this method returns false.- Returns:
- the selection 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
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setSelection
public void setSelection(boolean selected)
Sets the selection state of the receiver, if it is of typeCHECK,RADIO, orTOGGLE.When the receiver is of type
CHECKorRADIO, it is selected when it is checked. When it is of typeTOGGLE, it is selected when it is pushed in.- Parameters:
selected- the new selection 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
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getGrayed
public boolean getGrayed()
Returnstrueif the receiver is grayed, and false otherwise. When the widget does not have theCHECKstyle, return false.- Returns:
- the grayed state of the checkbox
- 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:
- 1.2
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setGrayed
public void setGrayed(boolean grayed)
Sets the grayed state of the receiver. This state change only applies if the control was created with the SWT.CHECK style.- Parameters:
grayed- the new grayed 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:
- 1.2
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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
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setImage
public void setImage(Image image)
Sets the receiver's image to the argument, which may benullindicating that no image should be displayed.- Parameters:
image- the image to display on the receiver (may benull)- 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
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getAlignment
public int getAlignment()
Returns a value which describes the position of the text or image in the receiver. The value will be one ofLEFT,RIGHTorCENTERunless the receiver is anARROWbutton, in which case, the alignment will indicate the direction of the arrow (one ofLEFT,RIGHT,UPorDOWN)- 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
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setAlignment
public void setAlignment(int alignment)
Controls how text, images and arrows will be displayed in the receiver. The argument should be one ofLEFT,RIGHTorCENTER.- 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
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computeSize
public Point computeSize(int wHint, int hHint, boolean changed)
Description copied from class:ControlReturns 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.DEFAULTis 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 befalse, so layout manager caches can be retained.- Overrides:
computeSizein classControl- Parameters:
wHint- the width hint (can beSWT.DEFAULT)hHint- the height hint (can beSWT.DEFAULT)changed-trueif the control's contents have changed, andfalseotherwise- 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"
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addSelectionListener
public void addSelectionListener(SelectionListener listener)
Adds the listener to the collection of listeners who will be notified when the control is selected, by sending it one of the messages defined in theSelectionListenerinterface.widgetSelectedis called when the control is selected.widgetDefaultSelectedis not called.- Parameters:
listener- the listener which should be notified- Throws:
java.lang.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
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removeSelectionListener
public void removeSelectionListener(SelectionListener listener)
Removes the listener from the collection of listeners who will be notified when the control is selected.- Parameters:
listener- the listener which should no longer be notified- Throws:
java.lang.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)
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setData
public void setData(java.lang.String key, java.lang.Object value)Description copied from class:WidgetSets the application defined property of the receiver with the specified name to the given value.Applications may associate arbitrary objects with the receiver in this fashion. If the objects stored in the properties need to be notified when the widget is disposed of, it is the application's responsibility to hook the Dispose event on the widget and do so.
- Overrides:
setDatain classControl- Parameters:
key- the name of the propertyvalue- the new value for the property- See Also:
Widget.getData(String)
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getAdapter
public <T> T getAdapter(java.lang.Class<T> adapter)
Description copied from class:WidgetImplementation of theAdaptableinterface.IMPORTANT: This method is not part of the RWT public API. It is marked public only so that it can be shared within the packages provided by RWT. It should never be accessed from application code.
- Specified by:
getAdapterin interfaceAdaptable- Overrides:
getAdapterin classControl- Parameters:
adapter- the lookup class- Returns:
- an object that can be cast to the given class or
nullif there is no adapter associated with the given class.
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