bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Button.java

/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;


import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.cocoa.*;

/**
 * Instances of this class represent a selectable user interface object that
 * issues notification when pressed and released. 
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>ARROW, CHECK, PUSH, RADIO, TOGGLE, FLAT</dd>
 * <dd>UP, DOWN, LEFT, RIGHT, CENTER</dd>
 * <dt><b>Events:</b></dt>
 * <dd>Selection</dd>
 * </dl>
 * <p>
 * Note: Only one of the styles ARROW, CHECK, PUSH, RADIO, and TOGGLE 
 * may be specified.
 * </p><p>
 * Note: Only one of the styles LEFT, RIGHT, and CENTER may be specified.
 * </p><p>
 * Note: Only one of the styles UP, DOWN, LEFT, and RIGHT may be specified
 * when the ARROW style is specified.
 * </p><p>
 * IMPORTANT: This class is intended to be subclassed <em>only</em>
 * within the SWT implementation.
 * </p>
 * 
 * @see <a href="http://www.eclipse.org/swt/snippets/#button">Button snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public class Button extends Control {
	String text = "";
	Image image;
	boolean grayed;
	
/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a composite control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see SWT#ARROW
 * @see SWT#CHECK
 * @see SWT#PUSH
 * @see SWT#RADIO
 * @see SWT#TOGGLE
 * @see SWT#FLAT
 * @see SWT#LEFT
 * @see SWT#RIGHT
 * @see SWT#CENTER
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public Button (Composite parent, int style) {
	super (parent, checkStyle (style));
}

/**
 * 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 <code>SelectionListener</code>
 * interface.
 * <p>
 * <code>widgetSelected</code> is called when the control is selected by the user.
 * <code>widgetDefaultSelected</code> is not called.
 * </p>
 *
 * @param listener the listener which should be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #removeSelectionListener
 * @see SelectionEvent
 */
public void addSelectionListener(SelectionListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener(listener);
	addListener(SWT.Selection,typedListener);
	addListener(SWT.DefaultSelection,typedListener);
}

static int checkStyle (int style) {
	style = checkBits (style, SWT.PUSH, SWT.ARROW, SWT.CHECK, SWT.RADIO, SWT.TOGGLE, 0);
	if ((style & (SWT.PUSH | SWT.TOGGLE)) != 0) {
		return checkBits (style, SWT.CENTER, SWT.LEFT, SWT.RIGHT, 0, 0, 0);
	}
	if ((style & (SWT.CHECK | SWT.RADIO)) != 0) {
		return checkBits (style, SWT.LEFT, SWT.RIGHT, SWT.CENTER, 0, 0, 0);
	}
	if ((style & SWT.ARROW) != 0) {
		style |= SWT.NO_FOCUS;
		return checkBits (style, SWT.UP, SWT.DOWN, SWT.LEFT, SWT.RIGHT, 0, 0);
	}
	return style;
}

void click () {
	postEvent (SWT.Selection);
}

public Point computeSize (int wHint, int hHint, boolean changed) {
	checkWidget();
	if ((style & SWT.ARROW) != 0) {
		// TODO use some OS metric instead of hardcoded values
		int width = wHint != SWT.DEFAULT ? wHint : 23;
		int height = hHint != SWT.DEFAULT ? hHint : 23;
		return new Point (width, height);
	}
	return super.computeSize(wHint, hHint, changed);
}

NSAttributedString createString() {
	NSMutableDictionary dict = NSMutableDictionary.dictionaryWithCapacity(4);
	if (foreground != null) {
		NSColor color = NSColor.colorWithDeviceRed(foreground.handle[0], foreground.handle[1], foreground.handle[2], 1);
		dict.setObject(color, OS.NSForegroundColorAttributeName());
	}
	if (font != null) {
		dict.setObject(font.handle, OS.NSFontAttributeName());
	}
	int alignment;
	if ((style & SWT.CENTER) != 0) {
		alignment = OS.NSCenterTextAlignment;
	} else if ((style & SWT.LEFT) != 0) {
		alignment = OS.NSLeftTextAlignment;
	} else {
		alignment = OS.NSRightTextAlignment;
	}
	NSMutableParagraphStyle pStyle = (NSMutableParagraphStyle)new NSMutableParagraphStyle().alloc().init();
	pStyle.autorelease();
	pStyle.setAlignment(alignment);
	dict.setObject(pStyle, OS.NSParagraphStyleAttributeName());
	char [] chars = new char [text.length ()];
	text.getChars (0, chars.length, chars, 0);
	int length = fixMnemonic (chars);
	NSString str = NSString.stringWithCharacters(chars, length);
	NSAttributedString attribStr = ((NSAttributedString)new NSAttributedString().alloc()).initWithString_attributes_(str, dict);
	attribStr.autorelease();
	return attribStr;
}

void createHandle () {
	NSButton widget = (NSButton)new SWTButton().alloc();
	widget.initWithFrame(new NSRect());
	int type = OS.NSMomentaryLightButton;
	if ((style & SWT.PUSH) != 0) {
		widget.setBezelStyle(OS.NSRoundedBezelStyle);
	} else if ((style & SWT.CHECK) != 0) {
		type = OS.NSSwitchButton;
		widget.setAllowsMixedState (true);
	} else if ((style & SWT.RADIO) != 0) {
		type = OS.NSRadioButton;		
	} else if ((style & SWT.TOGGLE) != 0) {
		type = OS.NSPushOnPushOffButton;
		widget.setBezelStyle(OS.NSRegularSquareBezelStyle);
	} else if ((style & SWT.ARROW) != 0) {
		widget.setBezelStyle(OS.NSRegularSquareBezelStyle);
	}
	widget.setButtonType(type);
	widget.setTitle(NSString.stringWith(""));
	widget.setImagePosition(OS.NSImageLeft);
	widget.setTarget(widget);
	widget.setAction(OS.sel_sendSelection);
	widget.setTag(jniRef);
	view = widget;	
	parent.contentView().addSubview_(widget);
	_setAlignment(style);
}

void drawRect(int id, NSRect rect) {
	super.drawRect(id, rect);
	if ((style & SWT.ARROW) == 0) return;

	NSRect frame = view.frame();
	int arrowSize = Math.min((int)frame.height, (int)frame.width) / 2;
	NSGraphicsContext context = NSGraphicsContext.currentContext();
	context.saveGraphicsState();
	NSPoint p1 = new NSPoint();
	p1.x = (float)Math.floor(-arrowSize / 2);
	p1.y = (float)Math.floor(-arrowSize / 2);
	NSPoint p2 = new NSPoint();
	p2.x = (float)Math.ceil(arrowSize / 2);
	p2.y = p1.y;
	NSPoint p3 = new NSPoint();
	p3.y = (float)Math.ceil(arrowSize / 2);

	NSBezierPath path = NSBezierPath.bezierPath();
	path.moveToPoint(p1);
	path.lineToPoint(p2);
	path.lineToPoint(p3);
	path.closePath();

	NSAffineTransform transform = NSAffineTransform.transform();
	if ((style & SWT.LEFT) != 0) {
		transform.rotateByDegrees(90);
	} else if ((style & SWT.UP) != 0) {
		transform.rotateByDegrees(180);
	} else if ((style & SWT.RIGHT) != 0) {
		transform.rotateByDegrees(-90);
	}
	path.transformUsingAffineTransform(transform);
	transform = NSAffineTransform.transform();
	transform.translateXBy(frame.width / 2, frame.height / 2);
	path.transformUsingAffineTransform(transform);

	NSColor color = isEnabled() ? NSColor.blackColor() : NSColor.disabledControlTextColor();
	color.set();
	path.fill();
	context.restoreGraphicsState();
}

/**
 * Returns a value which describes the position of the
 * text or image in the receiver. The value will be one of
 * <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code>
 * unless the receiver is an <code>ARROW</code> button, in 
 * which case, the alignment will indicate the direction of
 * the arrow (one of <code>LEFT</code>, <code>RIGHT</code>, 
 * <code>UP</code> or <code>DOWN</code>).
 *
 * @return the alignment 
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getAlignment () {
	checkWidget ();
	if ((style & SWT.ARROW) != 0) {
		if ((style & SWT.UP) != 0) return SWT.UP;
		if ((style & SWT.DOWN) != 0) return SWT.DOWN;
		if ((style & SWT.LEFT) != 0) return SWT.LEFT;
		if ((style & SWT.RIGHT) != 0) return SWT.RIGHT;
		return SWT.UP;
	}
	if ((style & SWT.LEFT) != 0) return SWT.LEFT;
	if ((style & SWT.CENTER) != 0) return SWT.CENTER;
	if ((style & SWT.RIGHT) != 0) return SWT.RIGHT;
	return SWT.LEFT;
}

/**
 * Returns <code>true</code> if the receiver is grayed,
 * and false otherwise. When the widget does not have
 * the <code>CHECK</code> style, return false.
 *
 * @return the grayed state of the checkbox
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @since 3.4
 */
public boolean getGrayed() {
	checkWidget ();
	if ((style &SWT.CHECK) != 0) return false;
	return grayed;
}

/**
 * Returns the receiver's image if it has one, or null
 * if it does not.
 *
 * @return the receiver's image
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Image getImage () {
	checkWidget();
	return image;
}

String getNameText () {
	return getText ();
}

/**
 * Returns <code>true</code> if the receiver is selected,
 * and false otherwise.
 * <p>
 * When the receiver is of type <code>CHECK</code> or <code>RADIO</code>,
 * it is selected when it is checked. When it is of type <code>TOGGLE</code>,
 * it is selected when it is pushed in. If the receiver is of any other type,
 * this method returns false.
 *
 * @return the selection state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public boolean getSelection () {
	checkWidget ();
	if ((style & (SWT.CHECK | SWT.RADIO | SWT.TOGGLE)) == 0) return false;
	if ((style & SWT.CHECK) != 0 && grayed) return ((NSButton)view).state() == OS.NSMixedState;
    return ((NSButton)view).state() == OS.NSOnState;
}

/**
 * Returns the receiver's text, which will be an empty
 * string if it has never been set or if the receiver is
 * an <code>ARROW</code> button.
 *
 * @return the receiver's text
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public String getText () {
	checkWidget ();
	return text;
}

void releaseWidget () {
	super.releaseWidget ();
	image = null;
	text = null;
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the control is selected by the user.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #addSelectionListener
 */
public void removeSelectionListener(SelectionListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook(SWT.Selection, listener);
	eventTable.unhook(SWT.DefaultSelection,listener);
}

void selectRadio () {
	/*
	* This code is intentionally commented.  When two groups
	* of radio buttons with the same parent are separated by
	* another control, the correct behavior should be that
	* the two groups act independently.  This is consistent
	* with radio tool and menu items.  The commented code
	* implements this behavior.
	*/
//	int index = 0;
//	Control [] children = parent._getChildren ();
//	while (index < children.length && children [index] != this) index++;
//	int i = index - 1;
//	while (i >= 0 && children [i].setRadioSelection (false)) --i;
//	int j = index + 1;
//	while (j < children.length && children [j].setRadioSelection (false)) j++;
//	setSelection (true);
	Control [] children = parent._getChildren ();
	for (int i=0; i<children.length; i++) {
		Control child = children [i];
		if (this != child) child.setRadioSelection (false);
	}
	setSelection (true);
}

void sendSelection () {
	if ((style & SWT.RADIO) != 0) {
		if ((parent.getStyle () & SWT.NO_RADIO_GROUP) == 0) {
			selectRadio ();
		}
	}
	if ((style & SWT.CHECK) != 0) {
		if (grayed && ((NSButton)view).state() == OS.NSOnState) {
			((NSButton)view).setState(OS.NSOffState);
		}
		if (!grayed && ((NSButton)view).state() == OS.NSMixedState) {
			((NSButton)view).setState(OS.NSOnState);
		}
	}
	postEvent (SWT.Selection);
}


/**
 * Controls how text, images and arrows will be displayed
 * in the receiver. The argument should be one of
 * <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code>
 * unless the receiver is an <code>ARROW</code> button, in 
 * which case, the argument indicates the direction of
 * the arrow (one of <code>LEFT</code>, <code>RIGHT</code>, 
 * <code>UP</code> or <code>DOWN</code>).
 *
 * @param alignment the new alignment 
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setAlignment (int alignment) {
	checkWidget ();
	_setAlignment (alignment);
	redraw ();
}

void _setAlignment (int alignment) {
	if ((style & SWT.ARROW) != 0) {
		if ((style & (SWT.UP | SWT.DOWN | SWT.LEFT | SWT.RIGHT)) == 0) return; 
		style &= ~(SWT.UP | SWT.DOWN | SWT.LEFT | SWT.RIGHT);
		style |= alignment & (SWT.UP | SWT.DOWN | SWT.LEFT | SWT.RIGHT);
//		int orientation = OS.kThemeDisclosureRight;
//		if ((style & SWT.UP) != 0) orientation = OS.kThemeDisclosureDown;
//		if ((style & SWT.DOWN) != 0) orientation = OS.kThemeDisclosureDown;
//		if ((style & SWT.LEFT) != 0) orientation = OS.kThemeDisclosureLeft;
//		OS.SetControl32BitValue (handle, orientation);
		return;
	}
	if ((alignment & (SWT.LEFT | SWT.RIGHT | SWT.CENTER)) == 0) return;
	style &= ~(SWT.LEFT | SWT.RIGHT | SWT.CENTER);
	style |= alignment & (SWT.LEFT | SWT.RIGHT | SWT.CENTER);
	/* text is still null when this is called from createHandle() */
	if (text != null) {
		((NSButton)view).setAttributedTitle(createString());
	}
//	/* Alignment not honoured when image and text is visible */
//	boolean bothVisible = text != null && text.length () > 0 && image != null;
//	if (bothVisible) {
//		if ((style & (SWT.RADIO | SWT.CHECK)) != 0) alignment = SWT.LEFT;
//		if ((style & (SWT.PUSH | SWT.TOGGLE)) != 0) alignment = SWT.CENTER;
//	}
//	int textAlignment = 0;
//	int graphicAlignment = 0;
//	if ((alignment & SWT.LEFT) != 0) {
//		textAlignment = OS.kControlBevelButtonAlignTextFlushLeft;
//		graphicAlignment = OS.kControlBevelButtonAlignLeft;
//	}
//	if ((alignment & SWT.CENTER) != 0) {
//		textAlignment = OS.kControlBevelButtonAlignTextCenter;
//		graphicAlignment = OS.kControlBevelButtonAlignCenter;
//	}
//	if ((alignment & SWT.RIGHT) != 0) {
//		textAlignment = OS.kControlBevelButtonAlignTextFlushRight;
//		graphicAlignment = OS.kControlBevelButtonAlignRight;
//	}
//	OS.SetControlData (handle, OS.kControlEntireControl, OS.kControlBevelButtonTextAlignTag, 2, new short [] {(short)textAlignment});
//	OS.SetControlData (handle, OS.kControlEntireControl, OS.kControlBevelButtonGraphicAlignTag, 2, new short [] {(short)graphicAlignment});
//	if (bothVisible) {
//		OS.SetControlData (handle, OS.kControlEntireControl, OS.kControlBevelButtonTextPlaceTag, 2, new short [] {(short)OS.kControlBevelButtonPlaceToRightOfGraphic});
//	}
}

void setBackground (float [] color) {
	NSColor nsColor;
	if (color == null) {
		return;	// TODO set to OS default
	} else {
		nsColor = NSColor.colorWithDeviceRed(color[0], color[1], color[2], 1);
	}
	NSButtonCell cell = new NSButtonCell(((NSButton)view).cell());
	cell.setBackgroundColor(nsColor);
}

void setDefault (boolean value) {
	if ((style & SWT.PUSH) == 0) return;
//	int window = OS.GetControlOwner (handle);
//	OS.SetWindowDefaultButton (window, value ? handle : 0);
}

void setForeground (float [] color) {
	((NSButton)view).setAttributedTitle(createString());
}

/**
 * Sets the grayed state of the receiver.  This state change 
 * only applies if the control was created with the SWT.CHECK
 * style.
 *
 * @param grayed the new grayed state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @since 3.4
 */
public void setGrayed(boolean grayed) {
	checkWidget ();
	if ((style & SWT.CHECK) == 0) return;
	boolean checked = getSelection ();
	this.grayed = grayed;
	if (checked) {
		if (grayed) {
			((NSButton) view).setState (OS.NSMixedState);
		} else {
			((NSButton) view).setState (OS.NSOnState);
		}
	}
}

/**
 * Sets the receiver's image to the argument, which may be
 * <code>null</code> indicating that no image should be displayed.
 * <p>
 * Note that a Button can display an image and text simultaneously
 * on Windows (starting with XP), GTK+ and OSX.  On other platforms,
 * a Button that has an image and text set into it will display the
 * image or text that was set most recently.
 * </p>
 * @param image the image to display on the receiver (may be <code>null</code>)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the image has been disposed</li>
 * </ul> 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setImage (Image image) {
	checkWidget();
	if ((style & SWT.ARROW) != 0) return;
	if (image != null && image.isDisposed ()) {
		error (SWT.ERROR_INVALID_ARGUMENT);
	}
	this.image = image;
	((NSButton)view).setImage(image.handle);
}

boolean setRadioSelection (boolean value){
	if ((style & SWT.RADIO) == 0) return false;
	if (getSelection () != value) {
		setSelection (value);
		postEvent (SWT.Selection);
	}
	return true;
}

/**
 * Sets the selection state of the receiver, if it is of type <code>CHECK</code>, 
 * <code>RADIO</code>, or <code>TOGGLE</code>.
 *
 * <p>
 * When the receiver is of type <code>CHECK</code> or <code>RADIO</code>,
 * it is selected when it is checked. When it is of type <code>TOGGLE</code>,
 * it is selected when it is pushed in.
 *
 * @param selected the new selection state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setSelection (boolean selected) {
	checkWidget();
	if ((style & (SWT.CHECK | SWT.RADIO | SWT.TOGGLE)) == 0) return;
	if (grayed) {
		((NSButton)view).setState (selected ? OS.NSMixedState : OS.NSOffState);
	} else {
		((NSButton)view).setState (selected ? OS.NSOnState : OS.NSOffState);
	}
}

/**
 * Sets the receiver's text.
 * <p>
 * This method sets the button label.  The label may include
 * the mnemonic character but must not contain line delimiters.
 * </p>
 * <p>
 * Mnemonics are indicated by an '&amp;' 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 emphasized in a platform specific
 * manner.  The mnemonic indicator character '&amp;' can be
 * escaped by doubling it in the string, causing a single
 * '&amp;' to be displayed.
 * </p><p>
 * Note that a Button can display an image and text simultaneously
 * on Windows (starting with XP), GTK+ and OSX.  On other platforms,
 * a Button that has an image and text set into it will display the
 * image or text that was set most recently.
 * </p>
 * @param string the new text
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the text is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setText (String string) {
	checkWidget();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	if ((style & SWT.ARROW) != 0) return;
	text = string;
	((NSButton)view).setAttributedTitle(createString());
}

int traversalCode (int key, NSEvent theEvent) {
	int code = super.traversalCode (key, theEvent);
	if ((style & SWT.RADIO) != 0) code |= SWT.TRAVERSE_ARROW_NEXT | SWT.TRAVERSE_ARROW_PREVIOUS;
	return code;
}

}