Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2011 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.graphics.*; import org.eclipse.swt.internal.*; /** * Instances of this class provide a description of a particular * event which occurred within SWT. The SWT <em>untyped listener</em> * API uses these instances for all event dispatching. * <p> * Note: For a given event, only the fields which are appropriate * will be filled in. The contents of the fields which are not used * by the event are unspecified. * </p> * * @see Listener * @see org.eclipse.swt.events.TypedEvent * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample, Listeners</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> */ public class Event { /** * the display where the event occurred * * @since 2.0 */ public Display display; /** * the widget that issued the event */ public Widget widget; /** * the type of event, as defined by the event type constants * in class <code>SWT</code> * * @see org.eclipse.swt.SWT */ public int type; /** * the event specific detail field, as defined by the detail constants * in class <code>SWT</code> * * @see org.eclipse.swt.SWT */ public int detail; /** * the item that the event occurred in (can be null) */ public Widget item; /** * the index of the item where the event occurred * * @since 3.2 */ public int index; /** * the graphics context to use when painting * that is configured to use the colors, font and * damaged region of the control. It is valid * only during the paint and must not be disposed */ public GC gc; /** * depending on the event type, the x offset of the bounding * rectangle of the region that requires painting or the * widget-relative, x coordinate of the pointer at the * time the mouse button was pressed or released */ public int x; /** * depending on the event type, the y offset of the bounding * rectangle of the region that requires painting or the * widget-relative, y coordinate of the pointer at the * time the mouse button was pressed or released */ public int y; /** * the width of the bounding rectangle of the * region that requires painting */ public int width; /** * the height of the bounding rectangle of the * region that requires painting */ public int height; /** * depending on the event type, the number of following * paint events that are pending which may always be zero * on some platforms, or the number of lines or pages to * scroll using the mouse wheel, or the number of times the * mouse has been clicked */ public int count; /** * the time that the event occurred. * * NOTE: This field is an unsigned integer and should * be AND'ed with 0xFFFFFFFFL so that it can be treated * as a signed long. */ public int time; /** * the button that was pressed or released; 1 for the * first button, 2 for the second button, and 3 for the * third button, etc. */ public int button; /** * depending on the event, the character represented by the key * that was typed. This is the final character that results * after all modifiers have been applied. For example, when the * user types Ctrl+A, the character value is 0x01 (ASCII SOH). * It is important that applications do not attempt to modify the * character value based on a stateMask (such as SWT.CTRL) or the * resulting character will not be correct. */ public char character; /** * depending on the event, the key code of the key that was typed, * as defined by the key code constants in class <code>SWT</code>. * When the character field of the event is ambiguous, this field * contains the unaffected value of the original character. For * example, typing Ctrl+M or Enter both result in the character '\r' * but the keyCode field will also contain '\r' when Enter was typed * and 'm' when Ctrl+M was typed. * * @see org.eclipse.swt.SWT */ public int keyCode; /** * depending on the event, the location of key specified by the * keyCode or character. The possible values for this field are * <code>SWT.LEFT</code>, <code>SWT.RIGHT</code>, <code>SWT.KEYPAD</code>, * or <code>SWT.NONE</code> representing the main keyboard area. * <p> * The location field can be used to differentiate key events that have * the same key code and character but are generated by different keys * in the keyboard. For example, a key down event with the key code equals * to SWT.SHIFT can be generated by the left and the right shift keys in the * keyboard. The location field can only be used to determine the location * of the key code or character in the current event. It does not * include information about the location of modifiers in state * mask. * </p> * * @see org.eclipse.swt.SWT#LEFT * @see org.eclipse.swt.SWT#RIGHT * @see org.eclipse.swt.SWT#KEYPAD * * @since 3.6 */ public int keyLocation; /** * depending on the event, the state of the keyboard modifier * keys and mouse masks at the time the event was generated. * * @see org.eclipse.swt.SWT#MODIFIER_MASK * @see org.eclipse.swt.SWT#BUTTON_MASK */ public int stateMask; /** * depending on the event, the range of text being modified. * Setting these fields only has effect during ImeComposition * events. */ public int start, end; /** * depending on the event, the new text that will be inserted. * Setting this field will change the text that is about to * be inserted or deleted. */ public String text; /** * Bidi segment offsets * @since 3.8 */ public int[] segments; /** * Characters to be applied on the segment boundaries * @since 3.8 */ public char[] segmentsChars; /** * depending on the event, a flag indicating whether the operation * should be allowed. Setting this field to false will cancel the * operation. */ public boolean doit = true; /** * a field for application use */ public Object data; /** * An array of the touch states for the current touch event. * * @since 3.7 */ public Touch[] touches; /** * If nonzero, a positive value indicates a swipe to the right, * and a negative value indicates a swipe to the left. * * @since 3.7 */ public int xDirection; /** * If nonzero, a positive value indicates a swipe in the up direction, * and a negative value indicates a swipe in the down direction. * * @since 3.7 */ public int yDirection; /** * The change in magnification. This value should be added to the current * scaling of an item to get the new scale factor. * * @since 3.7 */ public double magnification; /** * The number of degrees rotated on the track pad. * * @since 3.7 */ public double rotation; /** * Gets the bounds. * * @return a rectangle that is the bounds. */ public Rectangle getBounds() { return new Rectangle(x, y, width, height); } Rectangle getBoundsInPixels() { return DPIUtil.autoScaleUp(getBounds()); } Point getLocation() { return new Point(x, y); } Point getLocationInPixels() { return DPIUtil.autoScaleUp(new Point(x, y)); } /** * Sets the bounds. * * @param rect the new rectangle */ public void setBounds(Rectangle rect) { this.x = rect.x; this.y = rect.y; this.width = rect.width; this.height = rect.height; } void setBoundsInPixels(Rectangle rect) { setBounds(DPIUtil.autoScaleDown(rect)); } void setLocationInPixels(int x, int y) { this.x = DPIUtil.autoScaleDown(x); this.y = DPIUtil.autoScaleDown(y); } /** * Returns a string containing a concise, human-readable * description of the receiver. * * @return a string representation of the event */ @Override public String toString() { return "Event {type=" + type + " " + widget + " time=" + time + " data=" + data + " x=" + x + " y=" + y //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$//$NON-NLS-4$//$NON-NLS-5$//$NON-NLS-6$ + " width=" + width + " height=" + height + " detail=" + detail + "}"; //$NON-NLS-1$ } }