org.eclipse.swt.widgets.Item Maven / Gradle / Ivy

/*******************************************************************************
 * Copyright (c) 2000, 2013 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.graphics.*;

/**
 * This class is the abstract superclass of all non-windowed
 * user interface objects that occur within specific controls.
 * For example, a tree will contain tree items.
 * 
 * Styles:
 * (none)
 * Events:
 * (none)
 * 
 *
 * @see Sample code and further information
 */

public abstract class Item extends Widget {
	String text;
	Image image;

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * The item is added to the end of the items maintained by its parent.
 * 
 * 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.
 * 
 *
 * @param parent a widget which will be the parent of the new instance (cannot be null)
 * @param style the style of item to construct
 *
 * @exception IllegalArgumentException 
 *    ERROR_NULL_ARGUMENT - if the parent is null
 * 
 * @exception SWTException 
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
 * 
 *
 * @see SWT
 * @see Widget#getStyle
 */
public Item (Widget parent, int style) {
	super (parent, style);
	text = "";
}

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance,
 * and the index at which to place it in the items maintained
 * by its parent.
 * 
 * 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.
 * 
 *
 * @param parent a widget which will be the parent of the new instance (cannot be null)
 * @param style the style of item to construct
 * @param index the zero-relative index at which to store the receiver in its parent
 *
 * @exception IllegalArgumentException 
 *    ERROR_NULL_ARGUMENT - if the parent is null
 *    ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the parent (inclusive)
 * 
 * @exception SWTException 
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
 * 
 *
 * @see SWT
 * @see Widget#getStyle
 */
public Item (Widget parent, int style, int index) {
	this (parent, style);
}

protected void checkSubclass () {
	/* Do Nothing - Subclassing is allowed */
}

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

String getNameText () {
	return getText ();
}

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

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

/**
 * Sets the receiver's image to the argument, which may be
 * null indicating that no image should be displayed.
 *
 * @param image the image to display on the receiver (may be null)
 *
 * @exception IllegalArgumentException 
 *    ERROR_INVALID_ARGUMENT - if the image has been disposed 
 * 
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setImage (Image image) {
	checkWidget ();
	if (image != null && image.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT);
	this.image = image;
}

/**
 * Sets the receiver's text.
 *
 * @param string the new text
 *
 * @exception IllegalArgumentException 
 *    ERROR_NULL_ARGUMENT - if the text is null
 * 
 * @exception SWTException 
 *    ERROR_WIDGET_DISPOSED - if the receiver has been disposed
 *    ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
 * 
 */
public void setText (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	text = string;
}

boolean updateTextDirection(int textDirection) {
	if (((style  & SWT.FLIP_TEXT_DIRECTION) ^ textDirection) != 0) {
		style ^= SWT.FLIP_TEXT_DIRECTION;
		return true;
	}
	return false;
}


}