src/jexer/TField.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 jexer.bits.CellAttributes;
  34 import jexer.bits.GraphicsChars;
  35 import jexer.event.TKeypressEvent;
  36 import jexer.event.TMouseEvent;
  37 import static jexer.TKeypress.*;
  38
  39 /**
  40  * TField implements an editable text field.
  41  */
  42 public class TField extends TWidget {
  43
  44     /**
  45      * Field text.
  46      */
  47     protected String text = "";
  48
  49     /**
  50      * Get field text.
  51      *
  52      * @return field text
  53      */
  54     public final String getText() {
  55         return text;
  56     }
  57
  58     /**
  59      * If true, only allow enough characters that will fit in the width.  If
  60      * false, allow the field to scroll to the right.
  61      */
  62     protected boolean fixed = false;
  63
  64     /**
  65      * Current editing position within text.
  66      */
  67     protected int position = 0;
  68
  69     /**
  70      * Beginning of visible portion.
  71      */
  72     protected int windowStart = 0;
  73
  74     /**
  75      * If true, new characters are inserted at position.
  76      */
  77     protected boolean insertMode = true;
  78
  79     /**
  80      * Remember mouse state.
  81      */
  82     protected TMouseEvent mouse;
  83
  84     /**
  85      * The action to perform when the user presses enter.
  86      */
  87     protected TAction enterAction;
  88
  89     /**
  90      * The action to perform when the text is updated.
  91      */
  92     protected TAction updateAction;
  93
  94     /**
  95      * Public constructor.
  96      *
  97      * @param parent parent widget
  98      * @param x column relative to parent
  99      * @param y row relative to parent
 100      * @param width visible text width
 101      * @param fixed if true, the text cannot exceed the display width
 102      */
 103     public TField(final TWidget parent, final int x, final int y,
 104         final int width, final boolean fixed) {
 105
 106         this(parent, x, y, width, fixed, "", null, null);
 107     }
 108
 109     /**
 110      * Public constructor.
 111      *
 112      * @param parent parent widget
 113      * @param x column relative to parent
 114      * @param y row relative to parent
 115      * @param width visible text width
 116      * @param fixed if true, the text cannot exceed the display width
 117      * @param text initial text, default is empty string
 118      */
 119     public TField(final TWidget parent, final int x, final int y,
 120         final int width, final boolean fixed, final String text) {
 121
 122         this(parent, x, y, width, fixed, text, null, null);
 123     }
 124
 125     /**
 126      * Public constructor.
 127      *
 128      * @param parent parent widget
 129      * @param x column relative to parent
 130      * @param y row relative to parent
 131      * @param width visible text width
 132      * @param fixed if true, the text cannot exceed the display width
 133      * @param text initial text, default is empty string
 134      * @param enterAction function to call when enter key is pressed
 135      * @param updateAction function to call when the text is updated
 136      */
 137     public TField(final TWidget parent, final int x, final int y,
 138         final int width, final boolean fixed, final String text,
 139         final TAction enterAction, final TAction updateAction) {
 140
 141         // Set parent and window
 142         super(parent, x, y, width, 1);
 143
 144         setCursorVisible(true);
 145         this.fixed = fixed;
 146         this.text = text;
 147         this.enterAction = enterAction;
 148         this.updateAction = updateAction;
 149     }
 150
 151     /**
 152      * Returns true if the mouse is currently on the field.
 153      *
 154      * @return if true the mouse is currently on the field
 155      */
 156     protected boolean mouseOnField() {
 157         int rightEdge = getWidth() - 1;
 158         if ((mouse != null)
 159             && (mouse.getY() == 0)
 160             && (mouse.getX() >= 0)
 161             && (mouse.getX() <= rightEdge)
 162         ) {
 163             return true;
 164         }
 165         return false;
 166     }
 167
 168     /**
 169      * Dispatch to the action function.
 170      *
 171      * @param enter if true, the user pressed Enter, else this was an update
 172      * to the text.
 173      */
 174     protected void dispatch(final boolean enter) {
 175         if (enter) {
 176             if (enterAction != null) {
 177                 enterAction.DO();
 178             }
 179         } else {
 180             if (updateAction != null) {
 181                 updateAction.DO();
 182             }
 183         }
 184     }
 185
 186     /**
 187      * Draw the text field.
 188      */
 189     @Override
 190     public void draw() {
 191         CellAttributes fieldColor;
 192
 193         if (isAbsoluteActive()) {
 194             fieldColor = getTheme().getColor("tfield.active");
 195         } else {
 196             fieldColor = getTheme().getColor("tfield.inactive");
 197         }
 198
 199         int end = windowStart + getWidth();
 200         if (end > text.length()) {
 201             end = text.length();
 202         }
 203         getScreen().hLineXY(0, 0, getWidth(), GraphicsChars.HATCH, fieldColor);
 204         getScreen().putStrXY(0, 0, text.substring(windowStart, end),
 205             fieldColor);
 206
 207         // Fix the cursor, it will be rendered by TApplication.drawAll().
 208         updateCursor();
 209     }
 210
 211     /**
 212      * Update the cursor position.
 213      */
 214     protected void updateCursor() {
 215         if ((position > getWidth()) && fixed) {
 216             setCursorX(getWidth());
 217         } else if ((position - windowStart == getWidth()) && !fixed) {
 218             setCursorX(getWidth() - 1);
 219         } else {
 220             setCursorX(position - windowStart);
 221         }
 222     }
 223
 224     /**
 225      * Handle mouse button presses.
 226      *
 227      * @param mouse mouse button event
 228      */
 229     @Override
 230     public void onMouseDown(final TMouseEvent mouse) {
 231         this.mouse = mouse;
 232
 233         if ((mouseOnField()) && (mouse.isMouse1())) {
 234             // Move cursor
 235             int deltaX = mouse.getX() - getCursorX();
 236             position += deltaX;
 237             if (position > text.length()) {
 238                 position = text.length();
 239             }
 240             updateCursor();
 241             return;
 242         }
 243     }
 244
 245     /**
 246      * Handle keystrokes.
 247      *
 248      * @param keypress keystroke event
 249      */
 250     @Override
 251     public void onKeypress(final TKeypressEvent keypress) {
 252
 253         if (keypress.equals(kbLeft)) {
 254             if (position > 0) {
 255                 position--;
 256             }
 257             if (fixed == false) {
 258                 if ((position == windowStart) && (windowStart > 0)) {
 259                     windowStart--;
 260                 }
 261             }
 262             return;
 263         }
 264
 265         if (keypress.equals(kbRight)) {
 266             if (position < text.length()) {
 267                 position++;
 268                 if (fixed == true) {
 269                     if (position == getWidth()) {
 270                         position--;
 271                     }
 272                 } else {
 273                     if ((position - windowStart) == getWidth()) {
 274                         windowStart++;
 275                     }
 276                 }
 277             }
 278             return;
 279         }
 280
 281         if (keypress.equals(kbEnter)) {
 282             dispatch(true);
 283             return;
 284         }
 285
 286         if (keypress.equals(kbIns)) {
 287             insertMode = !insertMode;
 288             return;
 289         }
 290         if (keypress.equals(kbHome)) {
 291             position = 0;
 292             windowStart = 0;
 293             return;
 294         }
 295
 296         if (keypress.equals(kbEnd)) {
 297             position = text.length();
 298             if (fixed == true) {
 299                 if (position >= getWidth()) {
 300                     position = text.length() - 1;
 301                 }
 302             } else {
 303                 windowStart = text.length() - getWidth() + 1;
 304                 if (windowStart < 0) {
 305                     windowStart = 0;
 306                 }
 307             }
 308             return;
 309         }
 310
 311         if (keypress.equals(kbDel)) {
 312             if ((text.length() > 0) && (position < text.length())) {
 313                 text = text.substring(0, position)
 314                         + text.substring(position + 1);
 315             }
 316             return;
 317         }
 318
 319         if (keypress.equals(kbBackspace) || keypress.equals(kbBackspaceDel)) {
 320             if (position > 0) {
 321                 position--;
 322                 text = text.substring(0, position)
 323                         + text.substring(position + 1);
 324             }
 325             if (fixed == false) {
 326                 if ((position == windowStart)
 327                     && (windowStart > 0)
 328                 ) {
 329                     windowStart--;
 330                 }
 331             }
 332             dispatch(false);
 333             return;
 334         }
 335
 336         if (!keypress.getKey().isFnKey()
 337             && !keypress.getKey().isAlt()
 338             && !keypress.getKey().isCtrl()
 339         ) {
 340             // Plain old keystroke, process it
 341             if ((position == text.length())
 342                 && (text.length() < getWidth())) {
 343
 344                 // Append case
 345                 appendChar(keypress.getKey().getChar());
 346             } else if ((position < text.length())
 347                 && (text.length() < getWidth())) {
 348
 349                 // Overwrite or insert a character
 350                 if (insertMode == false) {
 351                     // Replace character
 352                     text = text.substring(0, position)
 353                             + keypress.getKey().getChar()
 354                             + text.substring(position + 1);
 355                     position++;
 356                 } else {
 357                     // Insert character
 358                     insertChar(keypress.getKey().getChar());
 359                 }
 360             } else if ((position < text.length())
 361                 && (text.length() >= getWidth())) {
 362
 363                 // Multiple cases here
 364                 if ((fixed == true) && (insertMode == true)) {
 365                     // Buffer is full, do nothing
 366                 } else if ((fixed == true) && (insertMode == false)) {
 367                     // Overwrite the last character, maybe move position
 368                     text = text.substring(0, position)
 369                             + keypress.getKey().getChar()
 370                             + text.substring(position + 1);
 371                     if (position < getWidth() - 1) {
 372                         position++;
 373                     }
 374                 } else if ((fixed == false) && (insertMode == false)) {
 375                     // Overwrite the last character, definitely move position
 376                     text = text.substring(0, position)
 377                             + keypress.getKey().getChar()
 378                             + text.substring(position + 1);
 379                     position++;
 380                 } else {
 381                     if (position == text.length()) {
 382                         // Append this character
 383                         appendChar(keypress.getKey().getChar());
 384                     } else {
 385                         // Insert this character
 386                         insertChar(keypress.getKey().getChar());
 387                     }
 388                 }
 389             } else {
 390                 assert (!fixed);
 391
 392                 // Append this character
 393                 appendChar(keypress.getKey().getChar());
 394             }
 395             dispatch(false);
 396             return;
 397         }
 398
 399         // Pass to parent for the things we don't care about.
 400         super.onKeypress(keypress);
 401     }
 402
 403     /**
 404      * Append char to the end of the field.
 405      *
 406      * @param ch = char to append
 407      */
 408     protected void appendChar(final char ch) {
 409         // Append the LAST character
 410         text += ch;
 411         position++;
 412
 413         assert (position == text.length());
 414
 415         if (fixed) {
 416             if (position == getWidth()) {
 417                 position--;
 418             }
 419         } else {
 420             if ((position - windowStart) == getWidth()) {
 421                 windowStart++;
 422             }
 423         }
 424     }
 425
 426     /**
 427      * Insert char somewhere in the middle of the field.
 428      *
 429      * @param ch char to append
 430      */
 431     protected void insertChar(final char ch) {
 432         text = text.substring(0, position) + ch + text.substring(position);
 433         position++;
 434         if ((position - windowStart) == getWidth()) {
 435             assert (!fixed);
 436             windowStart++;
 437         }
 438     }
 439
 440 }