ccombo.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.custom;


import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.accessibility.*;

/**
 * The CCombo class represents a selectable user interface object
 * that combines a text field and a list and issues notificiation
 * when an item is selected from the list.
 * <p>
 * Note that although this class is a subclass of <code>Composite</code>,
 * it does not make sense to add children to it, or set a layout on it.
 * </p>
 * <dl>
 * <dt><b>Styles:</b>
 * <dd>BORDER, READ_ONLY, FLAT</dd>
 * <dt><b>Events:</b>
 * <dd>Selection</dd>
 * </dl>
 */
public final class CCombo extends Composite {

	Text text;
	List list;
	int visibleItemCount = 5;
	Shell popup;
	Button arrow;
	boolean hasFocus;
	Listener listener, filter;
	Color foreground, background;
	Font font;
	
/**
 * 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 widget which will be the parent of the new instance (cannot be null)
 * @param style the style of widget 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>
 * </ul>
 *
 * @see SWT#BORDER
 * @see SWT#READ_ONLY
 * @see SWT#FLAT
 * @see Widget#getStyle()
 */
public CCombo (Composite parent, int style) {
	super (parent, style = checkStyle (style));
	
	int textStyle = SWT.SINGLE;
	if ((style & SWT.READ_ONLY) != 0) textStyle |= SWT.READ_ONLY;
	if ((style & SWT.FLAT) != 0) textStyle |= SWT.FLAT;
	text = new Text (this, textStyle);
	int arrowStyle = SWT.ARROW | SWT.DOWN;
	if ((style & SWT.FLAT) != 0) arrowStyle |= SWT.FLAT;
	arrow = new Button (this, arrowStyle);

	listener = new Listener () {
		public void handleEvent (Event event) {
			if (popup == event.widget) {
				popupEvent (event);
				return;
			}
			if (text == event.widget) {
				textEvent (event);
				return;
			}
			if (list == event.widget) {
				listEvent (event);
				return;
			}
			if (arrow == event.widget) {
				arrowEvent (event);
				return;
			}
			if (CCombo.this == event.widget) {
				comboEvent (event);
				return;
			}
			if (getShell () == event.widget) {
				handleFocus (SWT.FocusOut);
			}
		}
	};
	filter = new Listener() {
		public void handleEvent(Event event) {
			Shell shell = ((Control)event.widget).getShell ();
			if (shell == CCombo.this.getShell ()) {
				handleFocus (SWT.FocusOut);
			}
		}
	};
	
	int [] comboEvents = {SWT.Dispose, SWT.Move, SWT.Resize};
	for (int i=0; i<comboEvents.length; i++) this.addListener (comboEvents [i], listener);
	
	int [] textEvents = {SWT.KeyDown, SWT.KeyUp, SWT.Modify, SWT.MouseDown, SWT.MouseUp, SWT.Traverse, SWT.FocusIn};
	for (int i=0; i<textEvents.length; i++) text.addListener (textEvents [i], listener);
	
	int [] arrowEvents = {SWT.Selection, SWT.FocusIn};
	for (int i=0; i<arrowEvents.length; i++) arrow.addListener (arrowEvents [i], listener);
	
	createPopup(null, -1);
	initAccessible();
}
static int checkStyle (int style) {
	int mask = SWT.BORDER | SWT.READ_ONLY | SWT.FLAT | SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;
	return style & mask;
}
/**
* Adds an item.
* <p>
* The item is placed at the end of the list.
* Indexing is zero based.
*
* @param string the new item
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
* @exception SWTError(ERROR_NULL_ARGUMENT)
*	when the string is null
* @exception SWTError(ERROR_ITEM_NOT_ADDED)
*	when the item cannot be added
*/
public void add (String string) {
	checkWidget();
	if (string == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
	list.add (string);
}
/**
* Adds an item at an index.
* <p>
* The item is placed at an index in the list.
* Indexing is zero based.
*
* This operation will fail when the index is
* out of range.
*
* @param string the new item
* @param index the index for the item
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
* @exception SWTError(ERROR_NULL_ARGUMENT)
*	when the string is null
* @exception SWTError(ERROR_ITEM_NOT_ADDED)
*	when the item cannot be added
*/
public void add (String string, int index) {
	checkWidget();
	if (string == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
	list.add (string, index);
}
/**	 
* Adds the listener to receive events.
* <p>
*
* @param listener the listener
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
* @exception SWTError(ERROR_NULL_ARGUMENT)
*	when listener is null
*/
public void addModifyListener (ModifyListener listener) {
	checkWidget();
	if (listener == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Modify, typedListener);
}
/**	 
* Adds the listener to receive events.
* <p>
*
* @param listener the listener
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
* @exception SWTError(ERROR_NULL_ARGUMENT)
*	when listener is null
*/
public void addSelectionListener(SelectionListener listener) {
	checkWidget();
	if (listener == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Selection,typedListener);
	addListener (SWT.DefaultSelection,typedListener);
}
void arrowEvent (Event event) {
	switch (event.type) {
		case SWT.FocusIn: {
			handleFocus (SWT.FocusIn);
			break;
		}
		case SWT.Selection: {
			dropDown (!isDropped ());
			break;
		}
	}
}
/**
* Clears the current selection.
* <p>
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
*/
public void clearSelection () {
	checkWidget();
	text.clearSelection ();
	list.deselectAll ();
}
void comboEvent (Event event) {
	switch (event.type) {
		case SWT.Dispose:
			if (popup != null && !popup.isDisposed ()) {
				list.removeListener(SWT.Dispose, listener);
				popup.dispose ();
			}
			Shell shell = getShell ();
			shell.removeListener(SWT.Deactivate, listener);
			Display display = getDisplay();
			display.removeFilter(SWT.FocusIn, filter);
			popup = null;  
			text = null;  
			list = null;  
			arrow = null;
			break;
		case SWT.Move:
			dropDown(false);
			break;
		case SWT.Resize:
			internalLayout();
			break;
	}
}

public Point computeSize (int wHint, int hHint, boolean changed) {
	checkWidget();
	int width = 0, height = 0;
	Point textSize = text.computeSize (wHint, SWT.DEFAULT, changed);
	Point arrowSize = arrow.computeSize(SWT.DEFAULT, SWT.DEFAULT, changed);
	Point listSize = list.computeSize (wHint, SWT.DEFAULT, changed);
	int borderWidth = getBorderWidth();
	
	height = Math.max (hHint, Math.max(textSize.y, arrowSize.y)  + 2*borderWidth);
	width = Math.max (wHint, Math.max(textSize.x + arrowSize.x + 2*borderWidth, listSize.x + 2)  );
	return new Point (width, height);
}
void createPopup(String[] items, int selectionIndex) {		
		// create shell and list
		popup = new Shell (getShell(), SWT.NO_TRIM | SWT.ON_TOP);
		int style = getStyle();
		int listStyle = SWT.SINGLE | SWT.V_SCROLL;
		if ((style & SWT.FLAT) != 0) listStyle |= SWT.FLAT;
		if ((style & SWT.RIGHT_TO_LEFT) != 0) listStyle |= SWT.RIGHT_TO_LEFT;
		if ((style & SWT.LEFT_TO_RIGHT) != 0) listStyle |= SWT.LEFT_TO_RIGHT;
		list = new List (popup, listStyle);
		if (font != null) list.setFont(font);
		if (foreground != null) list.setForeground(foreground);
		if (background != null) list.setBackground(background);
		
		int [] popupEvents = {SWT.Close, SWT.Paint, SWT.Deactivate};
		for (int i=0; i<popupEvents.length; i++) popup.addListener (popupEvents [i], listener);
		int [] listEvents = {SWT.MouseUp, SWT.Selection, SWT.Traverse, SWT.KeyDown, SWT.KeyUp, SWT.FocusIn, SWT.Dispose};
		for (int i=0; i<listEvents.length; i++) list.addListener (listEvents [i], listener);
		
		if (items != null) list.setItems(items);
		if (selectionIndex != -1) list.setSelection(selectionIndex);
}
/**
* Deselects an item.
* <p>
* If the item at an index is selected, it is
* deselected.  If the item at an index is not
* selected, it remains deselected.  Indices
* that are out of range are ignored.  Indexing
* is zero based.
*
* @param index the index of the item
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
*/
public void deselect (int index) {
	checkWidget();
	list.deselect (index);
}
/**
* Deselects all items.
* <p>
*
* If an item is selected, it is deselected.
* If an item is not selected, it remains unselected.
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
*/
public void deselectAll () {
	checkWidget();
	list.deselectAll ();
}
void dropDown (boolean drop) {
	if (drop == isDropped ()) return;
	if (!drop) {
		popup.setVisible (false);
		text.setFocus();
		return;
	}

	if (getShell() != popup.getParent()) {
		String[] items = list.getItems();
		int selectionIndex = list.getSelectionIndex();
		list.removeListener(SWT.Dispose, listener);
		popup.dispose();
		popup = null;
		list = null;
		createPopup(items, selectionIndex);
	}
	
	Point size = getSize();
	int itemCount = list.getItemCount();
	itemCount = (itemCount == 0) ? visibleItemCount : Math.min(visibleItemCount, itemCount);
	int itemHeight = list.getItemHeight () * itemCount;
	Point listSize = list.computeSize (SWT.DEFAULT, itemHeight);
	list.setBounds (1, 1, Math.max (size.x - 2, listSize.x), listSize.y);
	
	int index = list.getSelectionIndex ();
	if (index != -1) list.setTopIndex (index);
	Display display = getDisplay ();
	Rectangle listRect = list.getBounds ();
	Rectangle parentRect = display.map (getParent (), null, getBounds());
	Point comboSize = getSize ();
	Rectangle displayRect = getMonitor().getClientArea();
	int width = Math.max (comboSize.x, listRect.width + 2);
	int height = listRect.height + 2;
	int x = parentRect.x;
	int y = parentRect.y + comboSize.y;
	if (y + height > displayRect.y + displayRect.height) y = parentRect.y - height;
	popup.setBounds (x, y, width, height);
	popup.setVisible (true);
	list.setFocus();
}
/* 
 * Return the Label immediately preceding the receiver in the z-order, 
 * or null if none. 
 */
Label getAssociatedLabel () {
	Control[] siblings = getParent().getChildren();
	for (int i = 0; i < siblings.length; i++) {
		if (siblings[i] == CCombo.this) {
			if (i > 0 && siblings[i-1] instanceof Label) {
				return (Label) siblings[i-1];
			}
		}
	}
	return null;
}
public Control [] getChildren () {
	checkWidget();
	return new Control [0];
}
/**
 * Gets the editable state.
 * 
 * @return true if the contents can be edited
 *
 * @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 3.0
 *
 */
public boolean getEditable () {
	checkWidget ();
	return text.getEditable();
}
/**
* Gets an item at an index.
* <p>
* Indexing is zero based.
*
* This operation will fail when the index is out
* of range or an item could not be queried from
* the OS.
*
* @param index the index of the item
* @return the item
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed
* @exception SWTError(ERROR_CANNOT_GET_ITEM)
*	when the operation fails
*/
public String getItem (int index) {
	checkWidget();
	return list.getItem (index);
}
/**
* Gets the number of items.
* <p>
* This operation will fail if the number of
* items could not be queried from the OS.
*
* @return the number of items in the widget
*
* @exception SWTError(ERROR_THREAD_INVALID_ACCESS)
*	when called from the wrong thread
* @exception SWTError(ERROR_WIDGET_DISPOSED)
*	when the widget has been disposed