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a3b510ab NR |
1 | /* |
2 | * This file is part of lanterna (http://code.google.com/p/lanterna/). | |
3 | * | |
4 | * lanterna is free software: you can redistribute it and/or modify | |
5 | * it under the terms of the GNU Lesser General Public License as published by | |
6 | * the Free Software Foundation, either version 3 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU Lesser General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public License | |
15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
16 | * | |
17 | * Copyright (C) 2010-2015 Martin | |
18 | */ | |
19 | package com.googlecode.lanterna.gui2; | |
20 | ||
21 | import com.googlecode.lanterna.TerminalSize; | |
22 | import com.googlecode.lanterna.input.KeyStroke; | |
23 | import com.googlecode.lanterna.input.KeyType; | |
24 | ||
25 | import java.util.List; | |
26 | import java.util.concurrent.CopyOnWriteArrayList; | |
27 | ||
28 | /** | |
29 | * The list box will display a number of items, of which one and only one can be marked as selected. | |
30 | * The user can select an item in the list box by pressing the return key or space bar key. If you | |
31 | * select one item when another item is already selected, the previously selected item will be | |
32 | * deselected and the highlighted item will be the selected one instead. | |
33 | * @author Martin | |
34 | */ | |
35 | public class RadioBoxList<V> extends AbstractListBox<V, RadioBoxList<V>> { | |
36 | /** | |
37 | * Listener interface that can be attached to the {@code RadioBoxList} in order to be notified on user actions | |
38 | */ | |
39 | public interface Listener { | |
40 | /** | |
41 | * Called by the {@code RadioBoxList} when the user changes which item is selected | |
42 | * @param selectedIndex Index of the newly selected item, or -1 if the selection has been cleared (can only be | |
43 | * done programmatically) | |
44 | * @param previousSelection The index of the previously selected item which is now no longer selected, or -1 if | |
45 | * nothing was previously selected | |
46 | */ | |
47 | void onSelectionChanged(int selectedIndex, int previousSelection); | |
48 | } | |
49 | ||
50 | private final List<Listener> listeners; | |
51 | private int checkedIndex; | |
52 | ||
53 | /** | |
54 | * Creates a new RadioCheckBoxList with no items. The size of the {@code RadioBoxList} will be as big as is required | |
55 | * to display all items. | |
56 | */ | |
57 | public RadioBoxList() { | |
58 | this(null); | |
59 | } | |
60 | ||
61 | /** | |
62 | * Creates a new RadioCheckBoxList with a specified size. If the items in the {@code RadioBoxList} cannot fit in the | |
63 | * size specified, scrollbars will be used | |
64 | * @param preferredSize Size of the {@code RadioBoxList} or {@code null} to have it try to be as big as necessary to | |
65 | * be able to draw all items | |
66 | */ | |
67 | public RadioBoxList(TerminalSize preferredSize) { | |
68 | super(preferredSize); | |
69 | this.listeners = new CopyOnWriteArrayList<Listener>(); | |
70 | this.checkedIndex = -1; | |
71 | } | |
72 | ||
73 | @Override | |
74 | protected ListItemRenderer<V,RadioBoxList<V>> createDefaultListItemRenderer() { | |
75 | return new RadioBoxListItemRenderer<V>(); | |
76 | } | |
77 | ||
78 | @Override | |
79 | public synchronized Result handleKeyStroke(KeyStroke keyStroke) { | |
80 | if(keyStroke.getKeyType() == KeyType.Enter || | |
81 | (keyStroke.getKeyType() == KeyType.Character && keyStroke.getCharacter() == ' ')) { | |
82 | checkedIndex = getSelectedIndex(); | |
83 | invalidate(); | |
84 | return Result.HANDLED; | |
85 | } | |
86 | return super.handleKeyStroke(keyStroke); | |
87 | } | |
88 | ||
89 | @Override | |
90 | public synchronized RadioBoxList<V> clearItems() { | |
91 | setCheckedIndex(-1); | |
92 | return super.clearItems(); | |
93 | } | |
94 | ||
95 | /** | |
96 | * This method will see if an object is the currently selected item in this RadioCheckBoxList | |
97 | * @param object Object to test if it's the selected one | |
98 | * @return {@code true} if the supplied object is what's currently selected in the list box, | |
99 | * {@code false} otherwise. Returns null if the supplied object is not an item in the list box. | |
100 | */ | |
101 | public synchronized Boolean isChecked(V object) { | |
102 | if(object == null) | |
103 | return null; | |
104 | ||
105 | if(indexOf(object) == -1) | |
106 | return null; | |
107 | ||
108 | return checkedIndex == indexOf(object); | |
109 | } | |
110 | ||
111 | /** | |
112 | * This method will see if an item, addressed by index, is the currently selected item in this | |
113 | * RadioCheckBoxList | |
114 | * @param index Index of the item to check if it's currently selected | |
115 | * @return {@code true} if the currently selected object is at the supplied index, | |
116 | * {@code false} otherwise. Returns false if the index is out of range. | |
117 | */ | |
118 | @SuppressWarnings("SimplifiableIfStatement") | |
119 | public synchronized boolean isChecked(int index) { | |
120 | if(index < 0 || index >= getItemCount()) { | |
121 | return false; | |
122 | } | |
123 | ||
124 | return checkedIndex == index; | |
125 | } | |
126 | ||
127 | /** | |
128 | * Sets the currently checked item by the value itself. If null, the selection is cleared. When changing selection, | |
129 | * any previously selected item is deselected. | |
130 | * @param item Item to be checked | |
131 | */ | |
132 | public synchronized void setCheckedItem(V item) { | |
133 | if(item == null) { | |
134 | setCheckedIndex(-1); | |
135 | } | |
136 | else { | |
137 | setCheckedItemIndex(indexOf(item)); | |
138 | } | |
139 | } | |
140 | ||
141 | /** | |
142 | * Sets the currently selected item by index. If the index is out of range, it does nothing. | |
143 | * @param index Index of the item to be selected | |
144 | */ | |
145 | public synchronized void setCheckedItemIndex(int index) { | |
146 | if(index < -1 || index >= getItemCount()) | |
147 | return; | |
148 | ||
149 | setCheckedIndex(index); | |
150 | } | |
151 | ||
152 | /** | |
153 | * @return The index of the item which is currently selected, or -1 if there is no selection | |
154 | */ | |
155 | public int getCheckedItemIndex() { | |
156 | return checkedIndex; | |
157 | } | |
158 | ||
159 | /** | |
160 | * @return The object currently selected, or null if there is no selection | |
161 | */ | |
162 | public synchronized V getCheckedItem() { | |
163 | if(checkedIndex == -1 || checkedIndex >= getItemCount()) | |
164 | return null; | |
165 | ||
166 | return getItemAt(checkedIndex); | |
167 | } | |
168 | ||
169 | /** | |
170 | * Un-checks the currently checked item (if any) and leaves the radio check box in a state where no item is checked. | |
171 | */ | |
172 | public synchronized void clearSelection() { | |
173 | setCheckedIndex(-1); | |
174 | } | |
175 | ||
176 | /** | |
177 | * Adds a new listener to the {@code RadioBoxList} that will be called on certain user actions | |
178 | * @param listener Listener to attach to this {@code RadioBoxList} | |
179 | * @return Itself | |
180 | */ | |
181 | public RadioBoxList<V> addListener(Listener listener) { | |
182 | if(listener != null && !listeners.contains(listener)) { | |
183 | listeners.add(listener); | |
184 | } | |
185 | return this; | |
186 | } | |
187 | ||
188 | /** | |
189 | * Removes a listener from this {@code RadioBoxList} so that if it had been added earlier, it will no longer be | |
190 | * called on user actions | |
191 | * @param listener Listener to remove from this {@code RadioBoxList} | |
192 | * @return Itself | |
193 | */ | |
194 | public RadioBoxList<V> removeListener(Listener listener) { | |
195 | listeners.remove(listener); | |
196 | return this; | |
197 | } | |
198 | ||
199 | private void setCheckedIndex(int index) { | |
200 | final int previouslyChecked = checkedIndex; | |
201 | this.checkedIndex = index; | |
202 | invalidate(); | |
203 | runOnGUIThreadIfExistsOtherwiseRunDirect(new Runnable() { | |
204 | @Override | |
205 | public void run() { | |
206 | for(Listener listener: listeners) { | |
207 | listener.onSelectionChanged(-1, previouslyChecked); | |
208 | } | |
209 | } | |
210 | }); | |
211 | } | |
212 | ||
213 | /** | |
214 | * Default renderer for this component which is used unless overridden. The selected state is drawn on the left side | |
215 | * of the item label using a "< >" block filled with an "o" if the item is the selected one | |
216 | * @param <V> | |
217 | */ | |
218 | public static class RadioBoxListItemRenderer<V> extends ListItemRenderer<V,RadioBoxList<V>> { | |
219 | @Override | |
220 | public int getHotSpotPositionOnLine(int selectedIndex) { | |
221 | return 1; | |
222 | } | |
223 | ||
224 | @Override | |
225 | public String getLabel(RadioBoxList<V> listBox, int index, V item) { | |
226 | String check = " "; | |
227 | if(listBox.checkedIndex == index) | |
228 | check = "o"; | |
229 | ||
230 | String text = (item != null ? item : "<null>").toString(); | |
231 | return "<" + check + "> " + text; | |
232 | } | |
233 | } | |
234 | ||
235 | } |