src/com/googlecode/lanterna/gui2/CheckBoxList.java

   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.ArrayList;
  26 import java.util.List;
  27 import java.util.concurrent.CopyOnWriteArrayList;
  28
  29 /**
  30  * This is a list box implementation where each item has its own checked state that can be toggled on and off
  31  * @author Martin
  32  */
  33 public class CheckBoxList<V> extends AbstractListBox<V, CheckBoxList<V>> {
  34     /**
  35      * Listener interface that can be attached to the {@code CheckBoxList} in order to be notified on user actions
  36      */
  37     public interface Listener {
  38         /**
  39          * Called by the {@code CheckBoxList} when the user changes the toggle state of one item
  40          * @param itemIndex Index of the item that was toggled
  41          * @param checked If the state of the item is now checked, this will be {@code true}, otherwise {@code false}
  42          */
  43         void onStatusChanged(int itemIndex, boolean checked);
  44     }
  45
  46     private final List<Listener> listeners;
  47     private final List<Boolean> itemStatus;
  48
  49     /**
  50      * Creates a new {@code CheckBoxList} that is initially empty and has no hardcoded preferred size, so it will
  51      * attempt to be as big as necessary to draw all items.
  52      */
  53     public CheckBoxList() {
  54         this(null);
  55     }
  56
  57     /**
  58      * Creates a new {@code CheckBoxList} that is initially empty and has a pre-defined size that it will request. If
  59      * there are more items that can fit in this size, the list box will use scrollbars.
  60      * @param preferredSize Size the list box should request, no matter how many items it contains
  61      */
  62     public CheckBoxList(TerminalSize preferredSize) {
  63         super(preferredSize);
  64         this.listeners = new CopyOnWriteArrayList<Listener>();
  65         this.itemStatus = new ArrayList<Boolean>();
  66     }
  67
  68     @Override
  69     protected ListItemRenderer<V,CheckBoxList<V>> createDefaultListItemRenderer() {
  70         return new CheckBoxListItemRenderer<V>();
  71     }
  72
  73     @Override
  74     public synchronized CheckBoxList<V> clearItems() {
  75         itemStatus.clear();
  76         return super.clearItems();
  77     }
  78
  79     @Override
  80     public CheckBoxList<V> addItem(V object) {
  81         return addItem(object, false);
  82     }
  83
  84     /**
  85      * Adds an item to the checkbox list with an explicit checked status
  86      * @param object Object to add to the list
  87      * @param checkedState If <code>true</code>, the new item will be initially checked
  88      * @return Itself
  89      */
  90     public synchronized CheckBoxList<V> addItem(V object, boolean checkedState) {
  91         itemStatus.add(checkedState);
  92         return super.addItem(object);
  93     }
  94
  95     /**
  96      * Checks if a particular item is part of the check box list and returns a boolean value depending on the toggle
  97      * state of the item.
  98      * @param object Object to check the status of
  99      * @return If the item wasn't found in the list box, {@code null} is returned, otherwise {@code true} or
 100      * {@code false} depending on checked state of the item
 101      */
 102     public synchronized Boolean isChecked(V object) {
 103         if(indexOf(object) == -1)
 104             return null;
 105
 106         return itemStatus.get(indexOf(object));
 107     }
 108
 109     /**
 110      * Checks if a particular item is part of the check box list and returns a boolean value depending on the toggle
 111      * state of the item.
 112      * @param index Index of the item to check the status of
 113      * @return If the index was not valid in the list box, {@code null} is returned, otherwise {@code true} or
 114      * {@code false} depending on checked state of the item at that index
 115      */
 116     public synchronized Boolean isChecked(int index) {
 117         if(index < 0 || index >= itemStatus.size())
 118             return null;
 119
 120         return itemStatus.get(index);
 121     }
 122
 123     /**
 124      * Programmatically sets the checked state of an item in the list box
 125      * @param object Object to set the checked state of
 126      * @param checked If {@code true}, then the item is set to checked, otherwise not
 127      * @return Itself
 128      */
 129     public synchronized CheckBoxList<V> setChecked(V object, boolean checked) {
 130         int index = indexOf(object);
 131         if(index != -1) {
 132             setChecked(index, checked);
 133         }
 134         return self();
 135     }
 136
 137     private void setChecked(final int index, final boolean checked) {
 138         itemStatus.set(index, checked);
 139         runOnGUIThreadIfExistsOtherwiseRunDirect(new Runnable() {
 140             @Override
 141             public void run() {
 142                 for(Listener listener: listeners) {
 143                     listener.onStatusChanged(index, checked);
 144                 }
 145             }
 146         });
 147     }
 148
 149     /**
 150      * Returns all the items in the list box that have checked state, as a list
 151      * @return List of all items in the list box that has checked state on
 152      */
 153     public synchronized List<V> getCheckedItems() {
 154         List<V> result = new ArrayList<V>();
 155         for(int i = 0; i < itemStatus.size(); i++) {
 156             if(itemStatus.get(i)) {
 157                 result.add(getItemAt(i));
 158             }
 159         }
 160         return result;
 161     }
 162
 163     /**
 164      * Adds a new listener to the {@code CheckBoxList} that will be called on certain user actions
 165      * @param listener Listener to attach to this {@code CheckBoxList}
 166      * @return Itself
 167      */
 168     public synchronized CheckBoxList<V> addListener(Listener listener) {
 169         if(listener != null && !listeners.contains(listener)) {
 170             listeners.add(listener);
 171         }
 172         return this;
 173     }
 174
 175     /**
 176      * Removes a listener from this {@code CheckBoxList} so that if it had been added earlier, it will no longer be
 177      * called on user actions
 178      * @param listener Listener to remove from this {@code CheckBoxList}
 179      * @return Itself
 180      */
 181     public CheckBoxList<V> removeListener(Listener listener) {
 182         listeners.remove(listener);
 183         return this;
 184     }
 185
 186     @Override
 187     public synchronized Result handleKeyStroke(KeyStroke keyStroke) {
 188         if(keyStroke.getKeyType() == KeyType.Enter ||
 189                 (keyStroke.getKeyType() == KeyType.Character && keyStroke.getCharacter() == ' ')) {
 190             if(itemStatus.get(getSelectedIndex()))
 191                 setChecked(getSelectedIndex(), Boolean.FALSE);
 192             else
 193                 setChecked(getSelectedIndex(), Boolean.TRUE);
 194             return Result.HANDLED;
 195         }
 196         return super.handleKeyStroke(keyStroke);
 197     }
 198
 199     /**
 200      * Default renderer for this component which is used unless overridden. The checked state is drawn on the left side
 201      * of the item label using a "[ ]" block filled with an X if the item has checked state on
 202      * @param <V>
 203      */
 204     public static class CheckBoxListItemRenderer<V> extends ListItemRenderer<V,CheckBoxList<V>> {
 205         @Override
 206         public int getHotSpotPositionOnLine(int selectedIndex) {
 207             return 1;
 208         }
 209
 210         @Override
 211         public String getLabel(CheckBoxList<V> listBox, int index, V item) {
 212             String check = " ";
 213             List<Boolean> itemStatus = listBox.itemStatus;
 214             if(itemStatus.get(index))
 215                 check = "x";
 216
 217             String text = item.toString();
 218             return "[" + check + "] " + text;
 219         }
 220     }
 221 }