The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2006 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.text; |
| 18 | |
| 19 | |
| 20 | /** |
| 21 | * Utility class for manipulating cursors and selections in CharSequences. |
| 22 | * A cursor is a selection where the start and end are at the same offset. |
| 23 | */ |
| 24 | public class Selection { |
| 25 | private Selection() { /* cannot be instantiated */ } |
| 26 | |
| 27 | /* |
| 28 | * Retrieving the selection |
| 29 | */ |
| 30 | |
| 31 | /** |
| 32 | * Return the offset of the selection anchor or cursor, or -1 if |
| 33 | * there is no selection or cursor. |
| 34 | */ |
| 35 | public static final int getSelectionStart(CharSequence text) { |
| 36 | if (text instanceof Spanned) |
| 37 | return ((Spanned) text).getSpanStart(SELECTION_START); |
| 38 | else |
| 39 | return -1; |
| 40 | } |
| 41 | |
| 42 | /** |
| 43 | * Return the offset of the selection edge or cursor, or -1 if |
| 44 | * there is no selection or cursor. |
| 45 | */ |
| 46 | public static final int getSelectionEnd(CharSequence text) { |
| 47 | if (text instanceof Spanned) |
| 48 | return ((Spanned) text).getSpanStart(SELECTION_END); |
| 49 | else |
| 50 | return -1; |
| 51 | } |
| 52 | |
| 53 | /* |
| 54 | * Setting the selection |
| 55 | */ |
| 56 | |
| 57 | // private static int pin(int value, int min, int max) { |
| 58 | // return value < min ? 0 : (value > max ? max : value); |
| 59 | // } |
| 60 | |
| 61 | /** |
| 62 | * Set the selection anchor to <code>start</code> and the selection edge |
| 63 | * to <code>stop</code>. |
| 64 | */ |
| 65 | public static void setSelection(Spannable text, int start, int stop) { |
| 66 | // int len = text.length(); |
| 67 | // start = pin(start, 0, len); XXX remove unless we really need it |
| 68 | // stop = pin(stop, 0, len); |
| 69 | |
| 70 | int ostart = getSelectionStart(text); |
| 71 | int oend = getSelectionEnd(text); |
| 72 | |
| 73 | if (ostart != start || oend != stop) { |
| 74 | text.setSpan(SELECTION_START, start, start, |
| 75 | Spanned.SPAN_POINT_POINT|Spanned.SPAN_INTERMEDIATE); |
| 76 | text.setSpan(SELECTION_END, stop, stop, |
| 77 | Spanned.SPAN_POINT_POINT); |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Move the cursor to offset <code>index</code>. |
| 83 | */ |
| 84 | public static final void setSelection(Spannable text, int index) { |
| 85 | setSelection(text, index, index); |
| 86 | } |
| 87 | |
| 88 | /** |
| 89 | * Select the entire text. |
| 90 | */ |
| 91 | public static final void selectAll(Spannable text) { |
| 92 | setSelection(text, 0, text.length()); |
| 93 | } |
| 94 | |
| 95 | /** |
| 96 | * Move the selection edge to offset <code>index</code>. |
| 97 | */ |
| 98 | public static final void extendSelection(Spannable text, int index) { |
| 99 | if (text.getSpanStart(SELECTION_END) != index) |
| 100 | text.setSpan(SELECTION_END, index, index, Spanned.SPAN_POINT_POINT); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Remove the selection or cursor, if any, from the text. |
| 105 | */ |
| 106 | public static final void removeSelection(Spannable text) { |
| 107 | text.removeSpan(SELECTION_START); |
| 108 | text.removeSpan(SELECTION_END); |
| 109 | } |
| 110 | |
| 111 | /* |
| 112 | * Moving the selection within the layout |
| 113 | */ |
| 114 | |
| 115 | /** |
| 116 | * Move the cursor to the buffer offset physically above the current |
| 117 | * offset, or return false if the cursor is already on the top line. |
| 118 | */ |
| 119 | public static boolean moveUp(Spannable text, Layout layout) { |
| 120 | int start = getSelectionStart(text); |
| 121 | int end = getSelectionEnd(text); |
| 122 | |
| 123 | if (start != end) { |
| 124 | int min = Math.min(start, end); |
| 125 | int max = Math.max(start, end); |
| 126 | |
| 127 | setSelection(text, min); |
| 128 | |
| 129 | if (min == 0 && max == text.length()) { |
| 130 | return false; |
| 131 | } |
| 132 | |
| 133 | return true; |
| 134 | } else { |
| 135 | int line = layout.getLineForOffset(end); |
| 136 | |
| 137 | if (line > 0) { |
| 138 | int move; |
| 139 | |
| 140 | if (layout.getParagraphDirection(line) == |
| 141 | layout.getParagraphDirection(line - 1)) { |
| 142 | float h = layout.getPrimaryHorizontal(end); |
| 143 | move = layout.getOffsetForHorizontal(line - 1, h); |
| 144 | } else { |
| 145 | move = layout.getLineStart(line - 1); |
| 146 | } |
| 147 | |
| 148 | setSelection(text, move); |
| 149 | return true; |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | return false; |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * Move the cursor to the buffer offset physically below the current |
| 158 | * offset, or return false if the cursor is already on the bottom line. |
| 159 | */ |
| 160 | public static boolean moveDown(Spannable text, Layout layout) { |
| 161 | int start = getSelectionStart(text); |
| 162 | int end = getSelectionEnd(text); |
| 163 | |
| 164 | if (start != end) { |
| 165 | int min = Math.min(start, end); |
| 166 | int max = Math.max(start, end); |
| 167 | |
| 168 | setSelection(text, max); |
| 169 | |
| 170 | if (min == 0 && max == text.length()) { |
| 171 | return false; |
| 172 | } |
| 173 | |
| 174 | return true; |
| 175 | } else { |
| 176 | int line = layout.getLineForOffset(end); |
| 177 | |
| 178 | if (line < layout.getLineCount() - 1) { |
| 179 | int move; |
| 180 | |
| 181 | if (layout.getParagraphDirection(line) == |
| 182 | layout.getParagraphDirection(line + 1)) { |
| 183 | float h = layout.getPrimaryHorizontal(end); |
| 184 | move = layout.getOffsetForHorizontal(line + 1, h); |
| 185 | } else { |
| 186 | move = layout.getLineStart(line + 1); |
| 187 | } |
| 188 | |
| 189 | setSelection(text, move); |
| 190 | return true; |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | return false; |
| 195 | } |
| 196 | |
| 197 | /** |
| 198 | * Move the cursor to the buffer offset physically to the left of |
| 199 | * the current offset, or return false if the cursor is already |
| 200 | * at the left edge of the line and there is not another line to move it to. |
| 201 | */ |
| 202 | public static boolean moveLeft(Spannable text, Layout layout) { |
| 203 | int start = getSelectionStart(text); |
| 204 | int end = getSelectionEnd(text); |
| 205 | |
| 206 | if (start != end) { |
| 207 | setSelection(text, chooseHorizontal(layout, -1, start, end)); |
| 208 | return true; |
| 209 | } else { |
| 210 | int to = layout.getOffsetToLeftOf(end); |
| 211 | |
| 212 | if (to != end) { |
| 213 | setSelection(text, to); |
| 214 | return true; |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | return false; |
| 219 | } |
| 220 | |
| 221 | /** |
| 222 | * Move the cursor to the buffer offset physically to the right of |
| 223 | * the current offset, or return false if the cursor is already at |
| 224 | * at the right edge of the line and there is not another line |
| 225 | * to move it to. |
| 226 | */ |
| 227 | public static boolean moveRight(Spannable text, Layout layout) { |
| 228 | int start = getSelectionStart(text); |
| 229 | int end = getSelectionEnd(text); |
| 230 | |
| 231 | if (start != end) { |
| 232 | setSelection(text, chooseHorizontal(layout, 1, start, end)); |
| 233 | return true; |
| 234 | } else { |
| 235 | int to = layout.getOffsetToRightOf(end); |
| 236 | |
| 237 | if (to != end) { |
| 238 | setSelection(text, to); |
| 239 | return true; |
| 240 | } |
| 241 | } |
| 242 | |
| 243 | return false; |
| 244 | } |
| 245 | |
| 246 | /** |
| 247 | * Move the selection end to the buffer offset physically above |
| 248 | * the current selection end. |
| 249 | */ |
| 250 | public static boolean extendUp(Spannable text, Layout layout) { |
| 251 | int end = getSelectionEnd(text); |
| 252 | int line = layout.getLineForOffset(end); |
| 253 | |
| 254 | if (line > 0) { |
| 255 | int move; |
| 256 | |
| 257 | if (layout.getParagraphDirection(line) == |
| 258 | layout.getParagraphDirection(line - 1)) { |
| 259 | float h = layout.getPrimaryHorizontal(end); |
| 260 | move = layout.getOffsetForHorizontal(line - 1, h); |
| 261 | } else { |
| 262 | move = layout.getLineStart(line - 1); |
| 263 | } |
| 264 | |
| 265 | extendSelection(text, move); |
| 266 | return true; |
| 267 | } else if (end != 0) { |
| 268 | extendSelection(text, 0); |
| 269 | return true; |
| 270 | } |
| 271 | |
| 272 | return true; |
| 273 | } |
| 274 | |
| 275 | /** |
| 276 | * Move the selection end to the buffer offset physically below |
| 277 | * the current selection end. |
| 278 | */ |
| 279 | public static boolean extendDown(Spannable text, Layout layout) { |
| 280 | int end = getSelectionEnd(text); |
| 281 | int line = layout.getLineForOffset(end); |
| 282 | |
| 283 | if (line < layout.getLineCount() - 1) { |
| 284 | int move; |
| 285 | |
| 286 | if (layout.getParagraphDirection(line) == |
| 287 | layout.getParagraphDirection(line + 1)) { |
| 288 | float h = layout.getPrimaryHorizontal(end); |
| 289 | move = layout.getOffsetForHorizontal(line + 1, h); |
| 290 | } else { |
| 291 | move = layout.getLineStart(line + 1); |
| 292 | } |
| 293 | |
| 294 | extendSelection(text, move); |
| 295 | return true; |
| 296 | } else if (end != text.length()) { |
| 297 | extendSelection(text, text.length()); |
| 298 | return true; |
| 299 | } |
| 300 | |
| 301 | return true; |
| 302 | } |
| 303 | |
| 304 | /** |
| 305 | * Move the selection end to the buffer offset physically to the left of |
| 306 | * the current selection end. |
| 307 | */ |
| 308 | public static boolean extendLeft(Spannable text, Layout layout) { |
| 309 | int end = getSelectionEnd(text); |
| 310 | int to = layout.getOffsetToLeftOf(end); |
| 311 | |
| 312 | if (to != end) { |
| 313 | extendSelection(text, to); |
| 314 | return true; |
| 315 | } |
| 316 | |
| 317 | return true; |
| 318 | } |
| 319 | |
| 320 | /** |
| 321 | * Move the selection end to the buffer offset physically to the right of |
| 322 | * the current selection end. |
| 323 | */ |
| 324 | public static boolean extendRight(Spannable text, Layout layout) { |
| 325 | int end = getSelectionEnd(text); |
| 326 | int to = layout.getOffsetToRightOf(end); |
| 327 | |
| 328 | if (to != end) { |
| 329 | extendSelection(text, to); |
| 330 | return true; |
| 331 | } |
| 332 | |
| 333 | return true; |
| 334 | } |
| 335 | |
| 336 | public static boolean extendToLeftEdge(Spannable text, Layout layout) { |
| 337 | int where = findEdge(text, layout, -1); |
| 338 | extendSelection(text, where); |
| 339 | return true; |
| 340 | } |
| 341 | |
| 342 | public static boolean extendToRightEdge(Spannable text, Layout layout) { |
| 343 | int where = findEdge(text, layout, 1); |
| 344 | extendSelection(text, where); |
| 345 | return true; |
| 346 | } |
| 347 | |
| 348 | public static boolean moveToLeftEdge(Spannable text, Layout layout) { |
| 349 | int where = findEdge(text, layout, -1); |
| 350 | setSelection(text, where); |
| 351 | return true; |
| 352 | } |
| 353 | |
| 354 | public static boolean moveToRightEdge(Spannable text, Layout layout) { |
| 355 | int where = findEdge(text, layout, 1); |
| 356 | setSelection(text, where); |
| 357 | return true; |
| 358 | } |
| 359 | |
| 360 | private static int findEdge(Spannable text, Layout layout, int dir) { |
| 361 | int pt = getSelectionEnd(text); |
| 362 | int line = layout.getLineForOffset(pt); |
| 363 | int pdir = layout.getParagraphDirection(line); |
| 364 | |
| 365 | if (dir * pdir < 0) { |
| 366 | return layout.getLineStart(line); |
| 367 | } else { |
| 368 | int end = layout.getLineEnd(line); |
| 369 | |
| 370 | if (line == layout.getLineCount() - 1) |
| 371 | return end; |
| 372 | else |
| 373 | return end - 1; |
| 374 | } |
| 375 | } |
| 376 | |
| 377 | private static int chooseHorizontal(Layout layout, int direction, |
| 378 | int off1, int off2) { |
| 379 | int line1 = layout.getLineForOffset(off1); |
| 380 | int line2 = layout.getLineForOffset(off2); |
| 381 | |
| 382 | if (line1 == line2) { |
| 383 | // same line, so it goes by pure physical direction |
| 384 | |
| 385 | float h1 = layout.getPrimaryHorizontal(off1); |
| 386 | float h2 = layout.getPrimaryHorizontal(off2); |
| 387 | |
| 388 | if (direction < 0) { |
| 389 | // to left |
| 390 | |
| 391 | if (h1 < h2) |
| 392 | return off1; |
| 393 | else |
| 394 | return off2; |
| 395 | } else { |
| 396 | // to right |
| 397 | |
| 398 | if (h1 > h2) |
| 399 | return off1; |
| 400 | else |
| 401 | return off2; |
| 402 | } |
| 403 | } else { |
| 404 | // different line, so which line is "left" and which is "right" |
| 405 | // depends upon the directionality of the text |
| 406 | |
| 407 | // This only checks at one end, but it's not clear what the |
| 408 | // right thing to do is if the ends don't agree. Even if it |
| 409 | // is wrong it should still not be too bad. |
| 410 | int line = layout.getLineForOffset(off1); |
| 411 | int textdir = layout.getParagraphDirection(line); |
| 412 | |
| 413 | if (textdir == direction) |
| 414 | return Math.max(off1, off2); |
| 415 | else |
| 416 | return Math.min(off1, off2); |
| 417 | } |
| 418 | } |
| 419 | |
Gilles Debunne | 2d0e87b | 2010-07-13 10:14:24 -0700 | [diff] [blame] | 420 | private static final class START implements NoCopySpan { } |
| 421 | private static final class END implements NoCopySpan { } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 422 | |
| 423 | /* |
| 424 | * Public constants |
| 425 | */ |
| 426 | |
| 427 | public static final Object SELECTION_START = new START(); |
| 428 | public static final Object SELECTION_END = new END(); |
| 429 | } |