src/jexer/TList.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * License: LGPLv3 or later
   5  *
   6  * This module is licensed under the GNU Lesser General Public License
   7  * Version 3.  Please see the file "COPYING" in this directory for more
   8  * information about the GNU Lesser General Public License Version 3.
   9  *
  10  *     Copyright (C) 2015  Kevin Lamonte
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Lesser General Public License
  14  * as published by the Free Software Foundation; either version 3 of
  15  * the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public
  23  * License along with this program; if not, see
  24  * http://www.gnu.org/licenses/, or write to the Free Software
  25  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  26  * 02110-1301 USA
  27  *
  28  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  29  * @version 1
  30  */
  31 package jexer;
  32
  33 import java.util.ArrayList;
  34 import java.util.List;
  35
  36 import jexer.bits.CellAttributes;
  37 import jexer.event.TKeypressEvent;
  38 import jexer.event.TMouseEvent;
  39 import static jexer.TKeypress.*;
  40
  41 /**
  42  * TList shows a list of strings, and lets the user select one.
  43  */
  44 public class TList extends TWidget {
  45
  46     /**
  47      * The list of strings to display.
  48      */
  49     private List<String> strings;
  50
  51     /**
  52      * Selected string.
  53      */
  54     private int selectedString = -1;
  55
  56     /**
  57      * Get the selection index.
  58      *
  59      * @return -1 if nothing is selected, otherwise the index into the list
  60      */
  61     public final int getSelectedIndex() {
  62         return selectedString;
  63     }
  64
  65     /**
  66      * Set the selected string index.
  67      *
  68      * @param index -1 to unselect, otherwise the index into the list
  69      */
  70     public final void setSelectedIndex(final int index) {
  71         selectedString = index;
  72     }
  73
  74     /**
  75      * Get the selected string.
  76      *
  77      * @return the selected string, or null of nothing is selected yet
  78      */
  79     public final String getSelected() {
  80         if ((selectedString >= 0) && (selectedString <= strings.size() - 1)) {
  81             return strings.get(selectedString);
  82         }
  83         return null;
  84     }
  85
  86     /**
  87      * Set the new list of strings to display.
  88      *
  89      * @param list new list of strings
  90      */
  91     public final void setList(final List<String> list) {
  92         strings.clear();
  93         strings.addAll(list);
  94         reflow();
  95     }
  96
  97     /**
  98      * Vertical scrollbar.
  99      */
 100     private TVScroller vScroller;
 101
 102     /**
 103      * Get the vertical scrollbar.  This is used by subclasses.
 104      *
 105      * @return the vertical scrollbar
 106      */
 107     public final TVScroller getVScroller() {
 108         return vScroller;
 109     }
 110
 111     /**
 112      * Horizontal scrollbar.
 113      */
 114     private THScroller hScroller;
 115
 116     /**
 117      * Get the horizontal scrollbar.  This is used by subclasses.
 118      *
 119      * @return the horizontal scrollbar
 120      */
 121     public final THScroller getHScroller() {
 122         return hScroller;
 123     }
 124
 125     /**
 126      * Maximum width of a single line.
 127      */
 128     private int maxLineWidth;
 129
 130     /**
 131      * The action to perform when the user selects an item (clicks or enter).
 132      */
 133     private TAction enterAction = null;
 134
 135     /**
 136      * The action to perform when the user navigates with keyboard.
 137      */
 138     private TAction moveAction = null;
 139
 140     /**
 141      * Perform user selection action.
 142      */
 143     public void dispatchEnter() {
 144         assert (selectedString >= 0);
 145         assert (selectedString < strings.size());
 146         if (enterAction != null) {
 147             enterAction.DO();
 148         }
 149     }
 150
 151     /**
 152      * Perform list movement action.
 153      */
 154     public void dispatchMove() {
 155         assert (selectedString >= 0);
 156         assert (selectedString < strings.size());
 157         if (moveAction != null) {
 158             moveAction.DO();
 159         }
 160     }
 161
 162     /**
 163      * Resize for a new width/height.
 164      */
 165     public void reflow() {
 166
 167         // Reset the lines
 168         selectedString = -1;
 169         maxLineWidth = 0;
 170
 171         for (int i = 0; i < strings.size(); i++) {
 172             String line = strings.get(i);
 173             if (line.length() > maxLineWidth) {
 174                 maxLineWidth = line.length();
 175             }
 176         }
 177
 178         // Start at the top
 179         if (vScroller == null) {
 180             vScroller = new TVScroller(this, getWidth() - 1, 0,
 181                 getHeight() - 1);
 182         } else {
 183             vScroller.setX(getWidth() - 1);
 184             vScroller.setHeight(getHeight() - 1);
 185         }
 186         vScroller.setBottomValue(strings.size() - getHeight() + 1);
 187         vScroller.setTopValue(0);
 188         vScroller.setValue(0);
 189         if (vScroller.getBottomValue() < 0) {
 190             vScroller.setBottomValue(0);
 191         }
 192         vScroller.setBigChange(getHeight() - 1);
 193
 194         // Start at the left
 195         if (hScroller == null) {
 196             hScroller = new THScroller(this, 0, getHeight() - 1,
 197                 getWidth() - 1);
 198         } else {
 199             hScroller.setY(getHeight() - 1);
 200             hScroller.setWidth(getWidth() - 1);
 201         }
 202         hScroller.setRightValue(maxLineWidth - getWidth() + 1);
 203         hScroller.setLeftValue(0);
 204         hScroller.setValue(0);
 205         if (hScroller.getRightValue() < 0) {
 206             hScroller.setRightValue(0);
 207         }
 208         hScroller.setBigChange(getWidth() - 1);
 209     }
 210
 211     /**
 212      * Public constructor.
 213      *
 214      * @param parent parent widget
 215      * @param strings list of strings to show
 216      * @param x column relative to parent
 217      * @param y row relative to parent
 218      * @param width width of text area
 219      * @param height height of text area
 220      */
 221     public TList(final TWidget parent, final List<String> strings, final int x,
 222         final int y, final int width, final int height) {
 223
 224         this(parent, strings, x, y, width, height, null);
 225     }
 226
 227     /**
 228      * Public constructor.
 229      *
 230      * @param parent parent widget
 231      * @param strings list of strings to show.  This is allowed to be null
 232      * and set later with setList() or by subclasses.
 233      * @param x column relative to parent
 234      * @param y row relative to parent
 235      * @param width width of text area
 236      * @param height height of text area
 237      * @param enterAction action to perform when an item is selected
 238      */
 239     public TList(final TWidget parent, final List<String> strings, final int x,
 240         final int y, final int width, final int height,
 241         final TAction enterAction) {
 242
 243         super(parent, x, y, width, height);
 244         this.enterAction = enterAction;
 245         this.strings = new ArrayList<String>();
 246         if (strings != null) {
 247             this.strings.addAll(strings);
 248         }
 249         reflow();
 250     }
 251
 252     /**
 253      * Public constructor.
 254      *
 255      * @param parent parent widget
 256      * @param strings list of strings to show.  This is allowed to be null
 257      * and set later with setList() or by subclasses.
 258      * @param x column relative to parent
 259      * @param y row relative to parent
 260      * @param width width of text area
 261      * @param height height of text area
 262      * @param enterAction action to perform when an item is selected
 263      * @param moveAction action to perform when the user navigates to a new
 264      * item with arrow/page keys
 265      */
 266     public TList(final TWidget parent, final List<String> strings, final int x,
 267         final int y, final int width, final int height,
 268         final TAction enterAction, final TAction moveAction) {
 269
 270         super(parent, x, y, width, height);
 271         this.enterAction = enterAction;
 272         this.moveAction = moveAction;
 273         this.strings = new ArrayList<String>();
 274         if (strings != null) {
 275             this.strings.addAll(strings);
 276         }
 277         reflow();
 278     }
 279
 280     /**
 281      * Draw the files list.
 282      */
 283     @Override
 284     public void draw() {
 285         CellAttributes color = null;
 286         int begin = vScroller.getValue();
 287         int topY = 0;
 288         for (int i = begin; i < strings.size(); i++) {
 289             String line = strings.get(i);
 290             if (hScroller.getValue() < line.length()) {
 291                 line = line.substring(hScroller.getValue());
 292             } else {
 293                 line = "";
 294             }
 295             if (i == selectedString) {
 296                 color = getTheme().getColor("tlist.selected");
 297             } else if (isAbsoluteActive()) {
 298                 color = getTheme().getColor("tlist");
 299             } else {
 300                 color = getTheme().getColor("tlist.inactive");
 301             }
 302             String formatString = "%-" + Integer.toString(getWidth() - 1) + "s";
 303             getScreen().putStringXY(0, topY, String.format(formatString, line),
 304                     color);
 305             topY++;
 306             if (topY >= getHeight() - 1) {
 307                 break;
 308             }
 309         }
 310
 311         if (isAbsoluteActive()) {
 312             color = getTheme().getColor("tlist");
 313         } else {
 314             color = getTheme().getColor("tlist.inactive");
 315         }
 316
 317         // Pad the rest with blank lines
 318         for (int i = topY; i < getHeight() - 1; i++) {
 319             getScreen().hLineXY(0, i, getWidth() - 1, ' ', color);
 320         }
 321     }
 322
 323     /**
 324      * Handle mouse press events.
 325      *
 326      * @param mouse mouse button press event
 327      */
 328     @Override
 329     public void onMouseDown(final TMouseEvent mouse) {
 330         if (mouse.isMouseWheelUp()) {
 331             vScroller.decrement();
 332             return;
 333         }
 334         if (mouse.isMouseWheelDown()) {
 335             vScroller.increment();
 336             return;
 337         }
 338
 339         if ((mouse.getX() < getWidth() - 1)
 340             && (mouse.getY() < getHeight() - 1)) {
 341             if (vScroller.getValue() + mouse.getY() < strings.size()) {
 342                 selectedString = vScroller.getValue() + mouse.getY();
 343             }
 344             dispatchEnter();
 345             return;
 346         }
 347
 348         // Pass to children
 349         super.onMouseDown(mouse);
 350     }
 351
 352     /**
 353      * Handle keystrokes.
 354      *
 355      * @param keypress keystroke event
 356      */
 357     @Override
 358     public void onKeypress(final TKeypressEvent keypress) {
 359         if (keypress.equals(kbLeft)) {
 360             hScroller.decrement();
 361         } else if (keypress.equals(kbRight)) {
 362             hScroller.increment();
 363         } else if (keypress.equals(kbUp)) {
 364             if (strings.size() > 0) {
 365                 if (selectedString >= 0) {
 366                     if (selectedString > 0) {
 367                         if (selectedString - vScroller.getValue() == 0) {
 368                             vScroller.decrement();
 369                         }
 370                         selectedString--;
 371                     }
 372                 } else {
 373                     selectedString = strings.size() - 1;
 374                 }
 375             }
 376             if (selectedString >= 0) {
 377                 dispatchMove();
 378             }
 379         } else if (keypress.equals(kbDown)) {
 380             if (strings.size() > 0) {
 381                 if (selectedString >= 0) {
 382                     if (selectedString < strings.size() - 1) {
 383                         selectedString++;
 384                         if (selectedString - vScroller.getValue() == getHeight() - 1) {
 385                             vScroller.increment();
 386                         }
 387                     }
 388                 } else {
 389                     selectedString = 0;
 390                 }
 391             }
 392             if (selectedString >= 0) {
 393                 dispatchMove();
 394             }
 395         } else if (keypress.equals(kbPgUp)) {
 396             vScroller.bigDecrement();
 397             if (selectedString >= 0) {
 398                 selectedString -= getHeight() - 1;
 399                 if (selectedString < 0) {
 400                     selectedString = 0;
 401                 }
 402             }
 403             if (selectedString >= 0) {
 404                 dispatchMove();
 405             }
 406         } else if (keypress.equals(kbPgDn)) {
 407             vScroller.bigIncrement();
 408             if (selectedString >= 0) {
 409                 selectedString += getHeight() - 1;
 410                 if (selectedString > strings.size() - 1) {
 411                     selectedString = strings.size() - 1;
 412                 }
 413             }
 414             if (selectedString >= 0) {
 415                 dispatchMove();
 416             }
 417         } else if (keypress.equals(kbHome)) {
 418             vScroller.toTop();
 419             if (strings.size() > 0) {
 420                 selectedString = 0;
 421             }
 422             if (selectedString >= 0) {
 423                 dispatchMove();
 424             }
 425         } else if (keypress.equals(kbEnd)) {
 426             vScroller.toBottom();
 427             if (strings.size() > 0) {
 428                 selectedString = strings.size() - 1;
 429             }
 430             if (selectedString >= 0) {
 431                 dispatchMove();
 432             }
 433         } else if (keypress.equals(kbTab)) {
 434             getParent().switchWidget(true);
 435         } else if (keypress.equals(kbShiftTab) || keypress.equals(kbBackTab)) {
 436             getParent().switchWidget(false);
 437         } else if (keypress.equals(kbEnter)) {
 438             if (selectedString >= 0) {
 439                 dispatchEnter();
 440             }
 441         } else {
 442             // Pass other keys (tab etc.) on
 443             super.onKeypress(keypress);
 444         }
 445     }
 446
 447 }