bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/ExpandBar.java - platform/eclipse.platform.swt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2018 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * 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.*;
 import org.eclipse.swt.internal.gtk.*;
 import org.eclipse.swt.internal.gtk3.*;
 import org.eclipse.swt.internal.gtk4.*;

 /**
  * Instances of this class support the layout of selectable
  * expand bar items.
  * <p>
  * The item children that may be added to instances of this class
  * must be of type <code>ExpandItem</code>.
  * </p>
  * <dl>
  * <dt><b>Styles:</b></dt>
  * <dd>V_SCROLL</dd>
  * <dt><b>Events:</b></dt>
  * <dd>Expand, Collapse</dd>
  * </dl>
  * <p>
  * IMPORTANT: This class is <em>not</em> intended to be subclassed.
  * </p>
  *
  * @see ExpandItem
  * @see ExpandEvent
  * @see ExpandListener
  * @see ExpandAdapter
  * @see <a href="http://www.eclipse.org/swt/snippets/#expandbar">ExpandBar 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>
  *
  * @since 3.2
  * @noextend This class is not intended to be subclassed by clients.
  */
 public class ExpandBar extends Composite {
 	ExpandItem [] items;
 	ExpandItem lastFocus;
 	int itemCount;
 	int spacing;

 /**
  * 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#V_SCROLL
  * @see Widget#checkSubclass
  * @see Widget#getStyle
  */
 public ExpandBar (Composite parent, int style) {
 	super (parent, style);
 }

 /**
  * Adds the listener to the collection of listeners who will
  * be notified when an item in the receiver is expanded or collapsed
  * by sending it one of the messages defined in the <code>ExpandListener</code>
  * interface.
  *
  * @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 ExpandListener
  * @see #removeExpandListener
  */
 public void addExpandListener (ExpandListener listener) {
 	checkWidget ();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	TypedListener typedListener = new TypedListener (listener);
 	addListener (SWT.Expand, typedListener);
 	addListener (SWT.Collapse, typedListener);
 }

 @Override
 protected void checkSubclass () {
 	if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
 }

 @Override
 Point computeSizeInPixels (int wHint, int hHint, boolean changed) {
 	if (wHint != SWT.DEFAULT && wHint < 0) wHint = 0;
 	if (hHint != SWT.DEFAULT && hHint < 0) hHint = 0;
 	Point size = computeNativeSize (handle, wHint, hHint, changed);
 	if (size.x == 0 && wHint == SWT.DEFAULT) size.x = DEFAULT_WIDTH;
 	if (size.y == 0 && hHint == SWT.DEFAULT) size.y = DEFAULT_HEIGHT;
 	int border = gtk_container_get_border_width_or_margin (handle);
 	size.x += 2 * border;
 	size.y += 2 * border;
 	return size;
 }

 @Override
 void createHandle (int index) {
 	state |= HANDLE;

 	fixedHandle = OS.g_object_new(display.gtk_fixed_get_type(), 0);
 	if (fixedHandle == 0) error(SWT.ERROR_NO_HANDLES);
 	if (!GTK.GTK4) GTK3.gtk_widget_set_has_window(fixedHandle, true);

 	handle = gtk_box_new (GTK.GTK_ORIENTATION_VERTICAL, false, 0);
 	if (handle == 0) error (SWT.ERROR_NO_HANDLES);

 	if ((style & SWT.V_SCROLL) != 0) {
 		if (GTK.GTK4) {
 			scrolledHandle = GTK4.gtk_scrolled_window_new();
 		} else {
 			scrolledHandle = GTK3.gtk_scrolled_window_new (0, 0);
 		}
 		if (scrolledHandle == 0) error (SWT.ERROR_NO_HANDLES);
 		GTK.gtk_scrolled_window_set_policy (scrolledHandle, GTK.GTK_POLICY_NEVER, GTK.GTK_POLICY_AUTOMATIC);

 		if (GTK.GTK4) {
 			OS.swt_fixed_add(fixedHandle, scrolledHandle);
 			GTK4.gtk_scrolled_window_set_child(scrolledHandle, handle);
 		} else {
 			GTK3.gtk_container_add (fixedHandle, scrolledHandle);
 			GTK3.gtk_container_add(scrolledHandle, handle);
 		}

 		if (!GTK.GTK4) {
 			long viewport = GTK3.gtk_bin_get_child (scrolledHandle);
 			GTK3.gtk_viewport_set_shadow_type (viewport, GTK.GTK_SHADOW_NONE);
 		}
 	} else {
 		if (GTK.GTK4) {
 			OS.swt_fixed_add(fixedHandle, handle);
 		} else {
 			GTK3.gtk_container_add (fixedHandle, handle);
 		}
 	}
 	gtk_container_set_border_width (handle, 0);
 	// In GTK 3 font description is inherited from parent widget which is not how SWT has always worked,
 	// reset to default font to get the usual behavior
 	setFontDescription(defaultFont().handle);
 }

 void createItem (ExpandItem item, int style, int index) {
 	if (!(0 <= index && index <= itemCount)) error (SWT.ERROR_INVALID_RANGE);
 	if (itemCount == items.length) {
 		ExpandItem [] newItems = new ExpandItem [itemCount + 4];
 		System.arraycopy (items, 0, newItems, 0, items.length);
 		items = newItems;
 	}
 	System.arraycopy (items, index, items, index + 1, itemCount - index);
 	items [index] = item;
 	itemCount++;
 	item.width = Math.max (0, getClientAreaInPixels ().width - spacing * 2);
 	layoutItems();
 }

 @Override
 void createWidget (int index) {
 	super.createWidget (index);
 	items = new ExpandItem [4];
 }

 void destroyItem (ExpandItem item) {
 	int index = 0;
 	while (index < itemCount) {
 		if (items [index] == item) break;
 		index++;
 	}
 	if (index == itemCount) return;
 	System.arraycopy (items, index + 1, items, index, --itemCount - index);
 	items [itemCount] = null;
 	layoutItems();
 }

 @Override
 long eventHandle () {
 	return fixedHandle;
 }

 @Override
 boolean forceFocus (long focusHandle) {
 	if (lastFocus != null && lastFocus.setFocus ()) return true;
 	for (int i = 0; i < itemCount; i++) {
 		ExpandItem item = items [i];
 		if (item.setFocus ()) return true;
 	}
 	return super.forceFocus (focusHandle);
 }

 @Override
 boolean hasFocus () {
 	for (int i=0; i<itemCount; i++) {
 		ExpandItem item = items [i];
 		if (item.hasFocus ()) return true;
 	}
 	return super.hasFocus();
 }

 @Override
 void hookEvents() {
 	super.hookEvents();

 	if (!GTK.GTK4) {
 		if (scrolledHandle != 0) OS.g_signal_connect_closure(scrolledHandle, OS.size_allocate, display.getClosure(SIZE_ALLOCATE), true);
 	}
 }

 /**
  * Returns the item at the given, zero-relative index in the
  * receiver. Throws an exception if the index is out of range.
  *
  * @param index the index of the item to return
  * @return the item at the given index
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</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 ExpandItem getItem (int index) {
 	checkWidget();
 	if (!(0 <= index && index < itemCount)) error (SWT.ERROR_INVALID_RANGE);
 	return items [index];
 }

 /**
  * Returns the number of items contained in the receiver.
  *
  * @return the number of items
  *
  * @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 getItemCount () {
 	checkWidget();
 	return itemCount;
 }

 /**
  * Returns an array of <code>ExpandItem</code>s which are the items
  * in the receiver.
  * <p>
  * Note: This is not the actual structure used by the receiver
  * to maintain its list of items, so modifying the array will
  * not affect the receiver.
  * </p>
  *
  * @return the items in the receiver
  *
  * @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 ExpandItem [] getItems () {
 	checkWidget ();
 	ExpandItem [] result = new ExpandItem [itemCount];
 	System.arraycopy (items, 0, result, 0, itemCount);
 	return result;
 }

 /**
  * Returns the receiver's spacing.
  *
  * @return the spacing
  *
  * @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 getSpacing () {
 	checkWidget ();
 	return DPIUtil.autoScaleDown(spacing);
 }

 @Override
 long gtk_key_press_event (long widget, long event) {
 	if (!hasFocus ()) return 0;
 	long result = super.gtk_key_press_event (widget, event);
 	if (result != 0) return result;
 	int index = 0;
 	while (index < itemCount) {
 		if (items [index].hasFocus ()) break;
 		index++;
 	}

 	int [] key = new int [1];
 	if (GTK.GTK4) {
 		key[0] = GDK.gdk_key_event_get_keyval(event);
 	} else {
 		GDK.gdk_event_get_keyval(event, key);
 	}

 	boolean next = false;
 	switch (key[0]) {
 		case GDK.GDK_Up:
 		case GDK.GDK_Left: next = false; break;
 		case GDK.GDK_Down:
 		case GDK.GDK_Right: next = true; break;
 		default: return result;
 	}
 	int start = index, offset = next ? 1 : -1;
 	while ((index = (index + offset + itemCount) % itemCount) != start) {
 		ExpandItem item = items [index];
 		if (item.setFocus ()) return result;
 	}
 	return result;
 }

 /**
  * Searches the receiver's list starting at the first item
  * (index 0) until an item is found that is equal to the
  * argument, and returns the index of that item. If no item
  * is found, returns -1.
  *
  * @param item the search item
  * @return the index of the item
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the item is null</li>
  *    <li>ERROR_INVALID_ARGUMENT - if the item 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 int indexOf (ExpandItem item) {
 	checkWidget();
 	if (item == null) error (SWT.ERROR_NULL_ARGUMENT);
 	for (int i = 0; i < itemCount; i++) {
 		if (items [i] == item) return i;
 	}
 	return -1;
 }

 void layoutItems() {
 	for (int i = 0; i < itemCount; i++) {
 		ExpandItem item = items [i];
 		if (item != null) item.resizeControl();
 	}
 }

 @Override
 long gtk_size_allocate (long widget, long allocation) {
 	long result = super.gtk_size_allocate (widget, allocation);
 	layoutItems();
 	return result;
 }

 @Override
 long parentingHandle () {
 	return fixedHandle;
 }

 @Override
 void releaseChildren (boolean destroy) {
 	for (int i = 0; i < itemCount; i++) {
 		ExpandItem item = items [i];
 		if (item != null && !item.isDisposed ()) {
 			item.release (false);
 		}
 	}
 	super.releaseChildren (destroy);
 }

 /**
  * Removes the listener from the collection of listeners who will
  * be notified when items in the receiver are expanded or collapsed.
  *
  * @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 ExpandListener
  * @see #addExpandListener
  */
 public void removeExpandListener (ExpandListener listener) {
 	checkWidget ();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	if (eventTable == null) return;
 	eventTable.unhook (SWT.Expand, listener);
 	eventTable.unhook (SWT.Collapse, listener);
 }

 @Override
 void reskinChildren (int flags) {
 	if (items != null) {
 		for (int i=0; i<items.length; i++) {
 			ExpandItem item = items [i];
 			if (item != null ) item.reskin (flags);
 		}
 	}
 	super.reskinChildren (flags);
 }

 @Override
 void setWidgetBackground  () {
 	GdkRGBA rgba = (state & BACKGROUND) != 0 ? getBackgroundGdkRGBA () : null;
 	super.setBackgroundGdkRGBA (handle, rgba);
 }

 @Override
 void setFontDescription (long font) {
 	super.setFontDescription (font);
 	for (int i = 0; i < itemCount; i++) {
 		items[i].setFontDescription (font);
 	}
 	layoutItems();
 }

 @Override
 void setForegroundGdkRGBA (GdkRGBA rgba) {
 	super.setForegroundGdkRGBA(rgba);
 	for (int i = 0; i < itemCount; i++) {
 		items[i].setForegroundRGBA (rgba);
 	}
 }

 @Override
 void setOrientation (boolean create) {
 	super.setOrientation (create);
 	if (items != null) {
 		for (int i=0; i<items.length; i++) {
 			if (items[i] != null) items[i].setOrientation (create);
 		}
 	}
 }

 /**
  * Sets the receiver's spacing. Spacing specifies the number of points allocated around
  * each item.
  *
  * @param spacing the spacing around each item
  *
  * @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 setSpacing (int spacing) {
 	checkWidget ();
 	setSpacingInPixels(DPIUtil.autoScaleUp(spacing));
 }

 void setSpacingInPixels (int spacing) {
 	checkWidget ();
 	if (spacing < 0) return;
 	if (spacing == this.spacing) return;
 	this.spacing = spacing;
 	GTK.gtk_box_set_spacing (handle, spacing);
 	gtk_container_set_border_width (handle, spacing);
 }

 @Override
 void updateScrollBarValue (ScrollBar bar) {
 	layoutItems();
 }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2018 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* 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.*;
	import org.eclipse.swt.internal.gtk.*;
	import org.eclipse.swt.internal.gtk3.*;
	import org.eclipse.swt.internal.gtk4.*;

	/**
	* Instances of this class support the layout of selectable
	* expand bar items.
	* <p>
	* The item children that may be added to instances of this class
	* must be of type <code>ExpandItem</code>.
	* </p>
	* <dl>
	* <dt><b>Styles:</b></dt>
	* <dd>V_SCROLL</dd>
	* <dt><b>Events:</b></dt>
	* <dd>Expand, Collapse</dd>
	* </dl>
	* <p>
	* IMPORTANT: This class is <em>not</em> intended to be subclassed.
	* </p>
	*
	* @see ExpandItem
	* @see ExpandEvent
	* @see ExpandListener
	* @see ExpandAdapter
	* @see <a href="http://www.eclipse.org/swt/snippets/#expandbar">ExpandBar 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>
	*
	* @since 3.2
	* @noextend This class is not intended to be subclassed by clients.
	*/
	public class ExpandBar extends Composite {
	ExpandItem [] items;
	ExpandItem lastFocus;
	int itemCount;
	int spacing;

	/**
	* 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#V_SCROLL
	* @see Widget#checkSubclass
	* @see Widget#getStyle
	*/
	public ExpandBar (Composite parent, int style) {
	super (parent, style);
	}

	/**
	* Adds the listener to the collection of listeners who will
	* be notified when an item in the receiver is expanded or collapsed
	* by sending it one of the messages defined in the <code>ExpandListener</code>
	* interface.
	*
	* @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 ExpandListener
	* @see #removeExpandListener
	*/
	public void addExpandListener (ExpandListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Expand, typedListener);
	addListener (SWT.Collapse, typedListener);
	}

	@Override
	protected void checkSubclass () {
	if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
	}

	@Override
	Point computeSizeInPixels (int wHint, int hHint, boolean changed) {
	if (wHint != SWT.DEFAULT && wHint < 0) wHint = 0;
	if (hHint != SWT.DEFAULT && hHint < 0) hHint = 0;
	Point size = computeNativeSize (handle, wHint, hHint, changed);
	if (size.x == 0 && wHint == SWT.DEFAULT) size.x = DEFAULT_WIDTH;
	if (size.y == 0 && hHint == SWT.DEFAULT) size.y = DEFAULT_HEIGHT;
	int border = gtk_container_get_border_width_or_margin (handle);
	size.x += 2 * border;
	size.y += 2 * border;
	return size;
	}

	@Override
	void createHandle (int index) {
	state \|= HANDLE;

	fixedHandle = OS.g_object_new(display.gtk_fixed_get_type(), 0);
	if (fixedHandle == 0) error(SWT.ERROR_NO_HANDLES);
	if (!GTK.GTK4) GTK3.gtk_widget_set_has_window(fixedHandle, true);

	handle = gtk_box_new (GTK.GTK_ORIENTATION_VERTICAL, false, 0);
	if (handle == 0) error (SWT.ERROR_NO_HANDLES);

	if ((style & SWT.V_SCROLL) != 0) {
	if (GTK.GTK4) {
	scrolledHandle = GTK4.gtk_scrolled_window_new();
	} else {
	scrolledHandle = GTK3.gtk_scrolled_window_new (0, 0);
	}
	if (scrolledHandle == 0) error (SWT.ERROR_NO_HANDLES);
	GTK.gtk_scrolled_window_set_policy (scrolledHandle, GTK.GTK_POLICY_NEVER, GTK.GTK_POLICY_AUTOMATIC);

	if (GTK.GTK4) {
	OS.swt_fixed_add(fixedHandle, scrolledHandle);
	GTK4.gtk_scrolled_window_set_child(scrolledHandle, handle);
	} else {
	GTK3.gtk_container_add (fixedHandle, scrolledHandle);
	GTK3.gtk_container_add(scrolledHandle, handle);
	}

	if (!GTK.GTK4) {
	long viewport = GTK3.gtk_bin_get_child (scrolledHandle);
	GTK3.gtk_viewport_set_shadow_type (viewport, GTK.GTK_SHADOW_NONE);
	}
	} else {
	if (GTK.GTK4) {
	OS.swt_fixed_add(fixedHandle, handle);
	} else {
	GTK3.gtk_container_add (fixedHandle, handle);
	}
	}
	gtk_container_set_border_width (handle, 0);
	// In GTK 3 font description is inherited from parent widget which is not how SWT has always worked,
	// reset to default font to get the usual behavior
	setFontDescription(defaultFont().handle);
	}

	void createItem (ExpandItem item, int style, int index) {
	if (!(0 <= index && index <= itemCount)) error (SWT.ERROR_INVALID_RANGE);
	if (itemCount == items.length) {
	ExpandItem [] newItems = new ExpandItem [itemCount + 4];
	System.arraycopy (items, 0, newItems, 0, items.length);
	items = newItems;
	}
	System.arraycopy (items, index, items, index + 1, itemCount - index);
	items [index] = item;
	itemCount++;
	item.width = Math.max (0, getClientAreaInPixels ().width - spacing * 2);
	layoutItems();
	}

	@Override
	void createWidget (int index) {
	super.createWidget (index);
	items = new ExpandItem [4];
	}

	void destroyItem (ExpandItem item) {
	int index = 0;
	while (index < itemCount) {
	if (items [index] == item) break;
	index++;
	}
	if (index == itemCount) return;
	System.arraycopy (items, index + 1, items, index, --itemCount - index);
	items [itemCount] = null;
	layoutItems();
	}

	@Override
	long eventHandle () {
	return fixedHandle;
	}

	@Override
	boolean forceFocus (long focusHandle) {
	if (lastFocus != null && lastFocus.setFocus ()) return true;
	for (int i = 0; i < itemCount; i++) {
	ExpandItem item = items [i];
	if (item.setFocus ()) return true;
	}
	return super.forceFocus (focusHandle);
	}

	@Override
	boolean hasFocus () {
	for (int i=0; i<itemCount; i++) {
	ExpandItem item = items [i];
	if (item.hasFocus ()) return true;
	}
	return super.hasFocus();
	}

	@Override
	void hookEvents() {
	super.hookEvents();

	if (!GTK.GTK4) {
	if (scrolledHandle != 0) OS.g_signal_connect_closure(scrolledHandle, OS.size_allocate, display.getClosure(SIZE_ALLOCATE), true);
	}
	}

	/**
	* Returns the item at the given, zero-relative index in the
	* receiver. Throws an exception if the index is out of range.
	*
	* @param index the index of the item to return
	* @return the item at the given index
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</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 ExpandItem getItem (int index) {
	checkWidget();
	if (!(0 <= index && index < itemCount)) error (SWT.ERROR_INVALID_RANGE);
	return items [index];
	}

	/**
	* Returns the number of items contained in the receiver.
	*
	* @return the number of items
	*
	* @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 getItemCount () {
	checkWidget();
	return itemCount;
	}

	/**
	* Returns an array of <code>ExpandItem</code>s which are the items
	* in the receiver.
	* <p>
	* Note: This is not the actual structure used by the receiver
	* to maintain its list of items, so modifying the array will
	* not affect the receiver.
	* </p>
	*
	* @return the items in the receiver
	*
	* @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 ExpandItem [] getItems () {
	checkWidget ();
	ExpandItem [] result = new ExpandItem [itemCount];
	System.arraycopy (items, 0, result, 0, itemCount);
	return result;
	}

	/**
	* Returns the receiver's spacing.
	*
	* @return the spacing
	*
	* @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 getSpacing () {
	checkWidget ();
	return DPIUtil.autoScaleDown(spacing);
	}

	@Override
	long gtk_key_press_event (long widget, long event) {
	if (!hasFocus ()) return 0;
	long result = super.gtk_key_press_event (widget, event);
	if (result != 0) return result;
	int index = 0;
	while (index < itemCount) {
	if (items [index].hasFocus ()) break;
	index++;
	}

	int [] key = new int [1];
	if (GTK.GTK4) {
	key[0] = GDK.gdk_key_event_get_keyval(event);
	} else {
	GDK.gdk_event_get_keyval(event, key);
	}

	boolean next = false;
	switch (key[0]) {
	case GDK.GDK_Up:
	case GDK.GDK_Left: next = false; break;
	case GDK.GDK_Down:
	case GDK.GDK_Right: next = true; break;
	default: return result;
	}
	int start = index, offset = next ? 1 : -1;
	while ((index = (index + offset + itemCount) % itemCount) != start) {
	ExpandItem item = items [index];
	if (item.setFocus ()) return result;
	}
	return result;
	}

	/**
	* Searches the receiver's list starting at the first item
	* (index 0) until an item is found that is equal to the
	* argument, and returns the index of that item. If no item
	* is found, returns -1.
	*
	* @param item the search item
	* @return the index of the item
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the item is null</li>
	* <li>ERROR_INVALID_ARGUMENT - if the item 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 int indexOf (ExpandItem item) {
	checkWidget();
	if (item == null) error (SWT.ERROR_NULL_ARGUMENT);
	for (int i = 0; i < itemCount; i++) {
	if (items [i] == item) return i;
	}
	return -1;
	}

	void layoutItems() {
	for (int i = 0; i < itemCount; i++) {
	ExpandItem item = items [i];
	if (item != null) item.resizeControl();
	}
	}

	@Override
	long gtk_size_allocate (long widget, long allocation) {
	long result = super.gtk_size_allocate (widget, allocation);
	layoutItems();
	return result;
	}

	@Override
	long parentingHandle () {
	return fixedHandle;
	}

	@Override
	void releaseChildren (boolean destroy) {
	for (int i = 0; i < itemCount; i++) {
	ExpandItem item = items [i];
	if (item != null && !item.isDisposed ()) {
	item.release (false);
	}
	}
	super.releaseChildren (destroy);
	}

	/**
	* Removes the listener from the collection of listeners who will
	* be notified when items in the receiver are expanded or collapsed.
	*
	* @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 ExpandListener
	* @see #addExpandListener
	*/
	public void removeExpandListener (ExpandListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Expand, listener);
	eventTable.unhook (SWT.Collapse, listener);
	}

	@Override
	void reskinChildren (int flags) {
	if (items != null) {
	for (int i=0; i<items.length; i++) {
	ExpandItem item = items [i];
	if (item != null ) item.reskin (flags);
	}
	}
	super.reskinChildren (flags);
	}

	@Override
	void setWidgetBackground () {
	GdkRGBA rgba = (state & BACKGROUND) != 0 ? getBackgroundGdkRGBA () : null;
	super.setBackgroundGdkRGBA (handle, rgba);
	}

	@Override
	void setFontDescription (long font) {
	super.setFontDescription (font);
	for (int i = 0; i < itemCount; i++) {
	items[i].setFontDescription (font);
	}
	layoutItems();
	}

	@Override
	void setForegroundGdkRGBA (GdkRGBA rgba) {
	super.setForegroundGdkRGBA(rgba);
	for (int i = 0; i < itemCount; i++) {
	items[i].setForegroundRGBA (rgba);
	}
	}

	@Override
	void setOrientation (boolean create) {
	super.setOrientation (create);
	if (items != null) {
	for (int i=0; i<items.length; i++) {
	if (items[i] != null) items[i].setOrientation (create);
	}
	}
	}

	/**
	* Sets the receiver's spacing. Spacing specifies the number of points allocated around
	* each item.
	*
	* @param spacing the spacing around each item
	*
	* @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 setSpacing (int spacing) {
	checkWidget ();
	setSpacingInPixels(DPIUtil.autoScaleUp(spacing));
	}

	void setSpacingInPixels (int spacing) {
	checkWidget ();
	if (spacing < 0) return;
	if (spacing == this.spacing) return;
	this.spacing = spacing;
	GTK.gtk_box_set_spacing (handle, spacing);
	gtk_container_set_border_width (handle, spacing);
	}

	@Override
	void updateScrollBarValue (ScrollBar bar) {
	layoutItems();
	}
	}