1 /******************************************************************************* 2 * Copyright (c) 2000, 2008 IBM Corporation and others. 3 * All rights reserved. This program and the accompanying materials 4 * are made available under the terms of the Eclipse Public License v1.0 5 * which accompanies this distribution, and is available at 6 * http://www.eclipse.org/legal/epl-v10.html 7 * 8 * Contributors: 9 * IBM Corporation - initial API and implementation 10 * Port to the D programming language: 11 * Frank Benoit <benoit@tionex.de> 12 *******************************************************************************/ 13 module org.eclipse.swt.events.TraverseEvent; 14 15 16 import org.eclipse.swt.widgets.Event; 17 import org.eclipse.swt.events.KeyEvent; 18 19 import java.lang.all; 20 21 /** 22 * Instances of this class are sent as a result of 23 * widget traversal actions. 24 * <p> 25 * The traversal event allows fine control over keyboard traversal 26 * in a control both to implement traversal and override the default 27 * traversal behavior defined by the system. This is achieved using 28 * two fields, <code>detail</code> and <code>doit</code>. 29 * </p><p> 30 * When a control is traversed, a traverse event is sent. The detail 31 * describes the type of traversal and the doit field indicates the default 32 * behavior of the system. For example, when a right arrow key is pressed 33 * in a text control, the detail field is <code>TRAVERSE_ARROW_NEXT</code> 34 * and the doit field is <code>false</code>, indicating that the system 35 * will not traverse to the next tab item and the arrow key will be 36 * delivered to the text control. If the same key is pressed in a radio 37 * button, the doit field will be <code>true</code>, indicating that 38 * traversal is to proceed to the next tab item, possibly another radio 39 * button in the group and that the arrow key is not to be delivered 40 * to the radio button. 41 * </p><p> 42 * How can the traversal event be used to implement traversal? 43 * When a tab key is pressed in a canvas, the detail field will be 44 * <code>TRAVERSE_TAB_NEXT</code> and the doit field will be 45 * <code>false</code>. The default behavior of the system is to 46 * provide no traversal for canvas controls. This means that by 47 * default in a canvas, a key listener will see every key that the 48 * user types, including traversal keys. To understand why this 49 * is so, it is important to understand that only the widget implementor 50 * can decide which traversal is appropriate for the widget. Returning 51 * to the <code>TRAVERSE_TAB_NEXT</code> example, a text widget implemented 52 * by a canvas would typically want to use the tab key to insert a 53 * tab character into the widget. A list widget implementation, on the 54 * other hand, would like the system default traversal behavior. Using 55 * only the doit flag, both implementations are possible. The text widget 56 * implementor sets doit to <code>false</code>, ensuring that the system 57 * will not traverse and that the tab key will be delivered to key listeners. 58 * The list widget implementor sets doit to <code>true</code>, indicating 59 * that the system should perform tab traversal and that the key should not 60 * be delivered to the list widget. 61 * </p><p> 62 * How can the traversal event be used to override system traversal? 63 * When the return key is pressed in a single line text control, the 64 * detail field is <code>TRAVERSE_RETURN</code> and the doit field 65 * is <code>true</code>. This means that the return key will be processed 66 * by the default button, not the text widget. If the text widget has 67 * a default selection listener, it will not run because the return key 68 * will be processed by the default button. Imagine that the text control 69 * is being used as an in-place editor and return is used to dispose the 70 * widget. Setting doit to <code>false</code> will stop the system from 71 * activating the default button but the key will be delivered to the text 72 * control, running the key and selection listeners for the text. How 73 * can <code>TRAVERSE_RETURN</code> be implemented so that the default button 74 * will not be activated and the text widget will not see the return key? 75 * This is achieved by setting doit to <code>true</code>, and the detail 76 * to <code>TRAVERSE_NONE</code>. 77 * </p><p> 78 * Note: A widget implementor will typically implement traversal using 79 * only the doit flag to either enable or disable system traversal. 80 * </p> 81 * 82 * @see TraverseListener 83 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> 84 */ 85 86 public final class TraverseEvent : KeyEvent { 87 88 /** 89 * The traversal type. 90 * <p><ul> 91 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_NONE}</li> 92 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_ESCAPE}</li> 93 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_RETURN}</li> 94 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_TAB_NEXT}</li> 95 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_TAB_PREVIOUS}</li> 96 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_ARROW_NEXT}</li> 97 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_ARROW_PREVIOUS}</li> 98 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_MNEMONIC}</li> 99 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_PAGE_NEXT}</li> 100 * <li>{@link org.eclipse.swt.SWT#TRAVERSE_PAGE_PREVIOUS}</li> 101 * </ul></p> 102 * 103 * Setting this field will change the type of traversal. 104 * For example, setting the detail to <code>TRAVERSE_NONE</code> 105 * causes no traversal action to be taken. 106 * 107 * When used in conjunction with the <code>doit</code> field, the 108 * traversal detail field can be useful when overriding the default 109 * traversal mechanism for a control. For example, setting the doit 110 * field to <code>false</code> will cancel the operation and allow 111 * the traversal key stroke to be delivered to the control. Setting 112 * the doit field to <code>true</code> indicates that the traversal 113 * described by the detail field is to be performed. 114 */ 115 public int detail; 116 117 //static const long serialVersionUID = 3257565105301239349L; 118 119 /** 120 * Constructs a new instance of this class based on the 121 * information in the given untyped event. 122 * 123 * @param e the untyped event containing the information 124 */ 125 public this(Event e) { 126 super(e); 127 this.detail = e.detail; 128 } 129 130 /** 131 * Returns a string containing a concise, human-readable 132 * description of the receiver. 133 * 134 * @return a string representation of the event 135 */ 136 public override String toString() { 137 return Format( "{} detail={}}", super.toString[ 0 .. $-1 ], detail ); 138 } 139 }