SpellChecker.java revision 24d146b966c87fd9c3b48027cbfb4238cb892ca5
1/* 2 * Copyright (C) 2011 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 17package android.widget; 18 19import android.content.Context; 20import android.text.Editable; 21import android.text.Selection; 22import android.text.SpannableStringBuilder; 23import android.text.Spanned; 24import android.text.method.WordIterator; 25import android.text.style.SpellCheckSpan; 26import android.text.style.SuggestionSpan; 27import android.util.Log; 28import android.view.textservice.SentenceSuggestionsInfo; 29import android.view.textservice.SpellCheckerSession; 30import android.view.textservice.SpellCheckerSession.SpellCheckerSessionListener; 31import android.view.textservice.SuggestionsInfo; 32import android.view.textservice.TextInfo; 33import android.view.textservice.TextServicesManager; 34 35import com.android.internal.util.ArrayUtils; 36 37import java.text.BreakIterator; 38import java.util.Locale; 39 40 41/** 42 * Helper class for TextView. Bridge between the TextView and the Dictionnary service. 43 * 44 * @hide 45 */ 46public class SpellChecker implements SpellCheckerSessionListener { 47 private static final String TAG = SpellChecker.class.getSimpleName(); 48 private static final boolean DBG = false; 49 50 // No more than this number of words will be parsed on each iteration to ensure a minimum 51 // lock of the UI thread 52 public static final int MAX_NUMBER_OF_WORDS = 50; 53 54 // Rough estimate, such that the word iterator interval usually does not need to be shifted 55 public static final int AVERAGE_WORD_LENGTH = 7; 56 57 // When parsing, use a character window of that size. Will be shifted if needed 58 public static final int WORD_ITERATOR_INTERVAL = AVERAGE_WORD_LENGTH * MAX_NUMBER_OF_WORDS; 59 60 // Pause between each spell check to keep the UI smooth 61 private final static int SPELL_PAUSE_DURATION = 400; // milliseconds 62 63 private static final int MIN_SENTENCE_LENGTH = 50; 64 65 private static final int USE_SPAN_RANGE = -1; 66 67 private final TextView mTextView; 68 69 SpellCheckerSession mSpellCheckerSession; 70 // We assume that the sentence level spell check will always provide better results than words. 71 // Although word SC has a sequential option. 72 private boolean mIsSentenceSpellCheckSupported; 73 final int mCookie; 74 75 // Paired arrays for the (id, spellCheckSpan) pair. A negative id means the associated 76 // SpellCheckSpan has been recycled and can be-reused. 77 // Contains null SpellCheckSpans after index mLength. 78 private int[] mIds; 79 private SpellCheckSpan[] mSpellCheckSpans; 80 // The mLength first elements of the above arrays have been initialized 81 private int mLength; 82 83 // Parsers on chunck of text, cutting text into words that will be checked 84 private SpellParser[] mSpellParsers = new SpellParser[0]; 85 86 private int mSpanSequenceCounter = 0; 87 88 private Locale mCurrentLocale; 89 90 // Shared by all SpellParsers. Cannot be shared with TextView since it may be used 91 // concurrently due to the asynchronous nature of onGetSuggestions. 92 private WordIterator mWordIterator; 93 94 private TextServicesManager mTextServicesManager; 95 96 private Runnable mSpellRunnable; 97 98 public SpellChecker(TextView textView) { 99 mTextView = textView; 100 101 // Arbitrary: these arrays will automatically double their sizes on demand 102 final int size = ArrayUtils.idealObjectArraySize(1); 103 mIds = new int[size]; 104 mSpellCheckSpans = new SpellCheckSpan[size]; 105 106 setLocale(mTextView.getTextServicesLocale()); 107 108 mCookie = hashCode(); 109 } 110 111 private void resetSession() { 112 closeSession(); 113 114 mTextServicesManager = (TextServicesManager) mTextView.getContext(). 115 getSystemService(Context.TEXT_SERVICES_MANAGER_SERVICE); 116 if (!mTextServicesManager.isSpellCheckerEnabled() 117 || mTextServicesManager.getCurrentSpellCheckerSubtype(true) == null) { 118 mSpellCheckerSession = null; 119 } else { 120 mSpellCheckerSession = mTextServicesManager.newSpellCheckerSession( 121 null /* Bundle not currently used by the textServicesManager */, 122 mCurrentLocale, this, 123 false /* means any available languages from current spell checker */); 124 mIsSentenceSpellCheckSupported = true; 125 } 126 127 // Restore SpellCheckSpans in pool 128 for (int i = 0; i < mLength; i++) { 129 mSpellCheckSpans[i].setSpellCheckInProgress(false); 130 mIds[i] = -1; 131 } 132 mLength = 0; 133 134 // Remove existing misspelled SuggestionSpans 135 mTextView.removeMisspelledSpans((Editable) mTextView.getText()); 136 } 137 138 private void setLocale(Locale locale) { 139 mCurrentLocale = locale; 140 141 resetSession(); 142 143 // Change SpellParsers' wordIterator locale 144 mWordIterator = new WordIterator(locale); 145 146 // This class is the listener for locale change: warn other locale-aware objects 147 mTextView.onLocaleChanged(); 148 } 149 150 /** 151 * @return true if a spell checker session has successfully been created. Returns false if not, 152 * for instance when spell checking has been disabled in settings. 153 */ 154 private boolean isSessionActive() { 155 return mSpellCheckerSession != null; 156 } 157 158 public void closeSession() { 159 if (mSpellCheckerSession != null) { 160 mSpellCheckerSession.close(); 161 } 162 163 final int length = mSpellParsers.length; 164 for (int i = 0; i < length; i++) { 165 mSpellParsers[i].stop(); 166 } 167 168 if (mSpellRunnable != null) { 169 mTextView.removeCallbacks(mSpellRunnable); 170 } 171 } 172 173 private int nextSpellCheckSpanIndex() { 174 for (int i = 0; i < mLength; i++) { 175 if (mIds[i] < 0) return i; 176 } 177 178 if (mLength == mSpellCheckSpans.length) { 179 final int newSize = mLength * 2; 180 int[] newIds = new int[newSize]; 181 SpellCheckSpan[] newSpellCheckSpans = new SpellCheckSpan[newSize]; 182 System.arraycopy(mIds, 0, newIds, 0, mLength); 183 System.arraycopy(mSpellCheckSpans, 0, newSpellCheckSpans, 0, mLength); 184 mIds = newIds; 185 mSpellCheckSpans = newSpellCheckSpans; 186 } 187 188 mSpellCheckSpans[mLength] = new SpellCheckSpan(); 189 mLength++; 190 return mLength - 1; 191 } 192 193 private void addSpellCheckSpan(Editable editable, int start, int end) { 194 final int index = nextSpellCheckSpanIndex(); 195 editable.setSpan(mSpellCheckSpans[index], start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 196 mIds[index] = mSpanSequenceCounter++; 197 } 198 199 public void removeSpellCheckSpan(SpellCheckSpan spellCheckSpan) { 200 for (int i = 0; i < mLength; i++) { 201 if (mSpellCheckSpans[i] == spellCheckSpan) { 202 mSpellCheckSpans[i].setSpellCheckInProgress(false); 203 mIds[i] = -1; 204 return; 205 } 206 } 207 } 208 209 public void onSelectionChanged() { 210 spellCheck(); 211 } 212 213 public void spellCheck(int start, int end) { 214 final Locale locale = mTextView.getTextServicesLocale(); 215 final boolean isSessionActive = isSessionActive(); 216 if (mCurrentLocale == null || (!(mCurrentLocale.equals(locale)))) { 217 setLocale(locale); 218 // Re-check the entire text 219 start = 0; 220 end = mTextView.getText().length(); 221 } else { 222 final boolean spellCheckerActivated = mTextServicesManager.isSpellCheckerEnabled(); 223 if (isSessionActive != spellCheckerActivated) { 224 // Spell checker has been turned of or off since last spellCheck 225 resetSession(); 226 } 227 } 228 229 if (!isSessionActive) return; 230 231 // Find first available SpellParser from pool 232 final int length = mSpellParsers.length; 233 for (int i = 0; i < length; i++) { 234 final SpellParser spellParser = mSpellParsers[i]; 235 if (spellParser.isFinished()) { 236 spellParser.parse(start, end); 237 return; 238 } 239 } 240 241 // No available parser found in pool, create a new one 242 SpellParser[] newSpellParsers = new SpellParser[length + 1]; 243 System.arraycopy(mSpellParsers, 0, newSpellParsers, 0, length); 244 mSpellParsers = newSpellParsers; 245 246 SpellParser spellParser = new SpellParser(); 247 mSpellParsers[length] = spellParser; 248 spellParser.parse(start, end); 249 } 250 251 private void spellCheck() { 252 if (mSpellCheckerSession == null) return; 253 254 Editable editable = (Editable) mTextView.getText(); 255 final int selectionStart = Selection.getSelectionStart(editable); 256 final int selectionEnd = Selection.getSelectionEnd(editable); 257 258 TextInfo[] textInfos = new TextInfo[mLength]; 259 int textInfosCount = 0; 260 261 for (int i = 0; i < mLength; i++) { 262 final SpellCheckSpan spellCheckSpan = mSpellCheckSpans[i]; 263 if (spellCheckSpan.isSpellCheckInProgress()) continue; 264 265 final int start = editable.getSpanStart(spellCheckSpan); 266 final int end = editable.getSpanEnd(spellCheckSpan); 267 268 // Do not check this word if the user is currently editing it 269 if (start >= 0 && end > start && (selectionEnd < start || selectionStart > end)) { 270 final String word = (editable instanceof SpannableStringBuilder) ? 271 ((SpannableStringBuilder) editable).substring(start, end) : 272 editable.subSequence(start, end).toString(); 273 spellCheckSpan.setSpellCheckInProgress(true); 274 textInfos[textInfosCount++] = new TextInfo(word, mCookie, mIds[i]); 275 if (DBG) { 276 Log.d(TAG, "create TextInfo: (" + i + "/" + mLength + ")" + word 277 + ", cookie = " + mCookie + ", seq = " 278 + mIds[i] + ", sel start = " + selectionStart + ", sel end = " 279 + selectionEnd + ", start = " + start + ", end = " + end); 280 } 281 } 282 } 283 284 if (textInfosCount > 0) { 285 if (textInfosCount < textInfos.length) { 286 TextInfo[] textInfosCopy = new TextInfo[textInfosCount]; 287 System.arraycopy(textInfos, 0, textInfosCopy, 0, textInfosCount); 288 textInfos = textInfosCopy; 289 } 290 291 if (mIsSentenceSpellCheckSupported) { 292 mSpellCheckerSession.getSentenceSuggestions( 293 textInfos, SuggestionSpan.SUGGESTIONS_MAX_SIZE); 294 } else { 295 mSpellCheckerSession.getSuggestions(textInfos, SuggestionSpan.SUGGESTIONS_MAX_SIZE, 296 false /* TODO Set sequentialWords to true for initial spell check */); 297 } 298 } 299 } 300 301 private SpellCheckSpan onGetSuggestionsInternal( 302 SuggestionsInfo suggestionsInfo, int offset, int length) { 303 if (suggestionsInfo == null || suggestionsInfo.getCookie() != mCookie) { 304 return null; 305 } 306 final Editable editable = (Editable) mTextView.getText(); 307 final int sequenceNumber = suggestionsInfo.getSequence(); 308 for (int k = 0; k < mLength; ++k) { 309 if (sequenceNumber == mIds[k]) { 310 final int attributes = suggestionsInfo.getSuggestionsAttributes(); 311 final boolean isInDictionary = 312 ((attributes & SuggestionsInfo.RESULT_ATTR_IN_THE_DICTIONARY) > 0); 313 final boolean looksLikeTypo = 314 ((attributes & SuggestionsInfo.RESULT_ATTR_LOOKS_LIKE_TYPO) > 0); 315 316 final SpellCheckSpan spellCheckSpan = mSpellCheckSpans[k]; 317 //TODO: we need to change that rule for results from a sentence-level spell 318 // checker that will probably be in dictionary. 319 if (!isInDictionary && looksLikeTypo) { 320 createMisspelledSuggestionSpan( 321 editable, suggestionsInfo, spellCheckSpan, offset, length); 322 } 323 return spellCheckSpan; 324 } 325 } 326 return null; 327 } 328 329 @Override 330 public void onGetSuggestions(SuggestionsInfo[] results) { 331 final Editable editable = (Editable) mTextView.getText(); 332 for (int i = 0; i < results.length; ++i) { 333 final SpellCheckSpan spellCheckSpan = 334 onGetSuggestionsInternal(results[i], USE_SPAN_RANGE, USE_SPAN_RANGE); 335 if (spellCheckSpan != null) { 336 editable.removeSpan(spellCheckSpan); 337 } 338 } 339 scheduleNewSpellCheck(); 340 } 341 342 @Override 343 public void onGetSentenceSuggestions(SentenceSuggestionsInfo[] results) { 344 final Editable editable = (Editable) mTextView.getText(); 345 346 for (int i = 0; i < results.length; ++i) { 347 final SentenceSuggestionsInfo ssi = results[i]; 348 if (ssi == null) { 349 continue; 350 } 351 SpellCheckSpan spellCheckSpan = null; 352 for (int j = 0; j < ssi.getSuggestionsCount(); ++j) { 353 final SuggestionsInfo suggestionsInfo = ssi.getSuggestionsInfoAt(j); 354 if (suggestionsInfo == null) { 355 continue; 356 } 357 final int offset = ssi.getOffsetAt(j); 358 final int length = ssi.getLengthAt(j); 359 final SpellCheckSpan scs = onGetSuggestionsInternal( 360 suggestionsInfo, offset, length); 361 if (spellCheckSpan == null && scs != null) { 362 // the spellCheckSpan is shared by all the "SuggestionsInfo"s in the same 363 // SentenceSuggestionsInfo 364 spellCheckSpan = scs; 365 } 366 } 367 if (spellCheckSpan != null) { 368 editable.removeSpan(spellCheckSpan); 369 } 370 } 371 scheduleNewSpellCheck(); 372 } 373 374 private void scheduleNewSpellCheck() { 375 if (mSpellRunnable == null) { 376 mSpellRunnable = new Runnable() { 377 @Override 378 public void run() { 379 final int length = mSpellParsers.length; 380 for (int i = 0; i < length; i++) { 381 final SpellParser spellParser = mSpellParsers[i]; 382 if (!spellParser.isFinished()) { 383 spellParser.parse(); 384 break; // run one spell parser at a time to bound running time 385 } 386 } 387 } 388 }; 389 } else { 390 mTextView.removeCallbacks(mSpellRunnable); 391 } 392 393 mTextView.postDelayed(mSpellRunnable, SPELL_PAUSE_DURATION); 394 } 395 396 private void createMisspelledSuggestionSpan(Editable editable, SuggestionsInfo suggestionsInfo, 397 SpellCheckSpan spellCheckSpan, int offset, int length) { 398 final int spellCheckSpanStart = editable.getSpanStart(spellCheckSpan); 399 final int spellCheckSpanEnd = editable.getSpanEnd(spellCheckSpan); 400 if (spellCheckSpanStart < 0 || spellCheckSpanEnd <= spellCheckSpanStart) 401 return; // span was removed in the meantime 402 403 final int suggestionsCount = suggestionsInfo.getSuggestionsCount(); 404 if (suggestionsCount <= 0) { 405 // A negative suggestion count is possible 406 return; 407 } 408 409 final int start; 410 final int end; 411 if (offset != USE_SPAN_RANGE && length != USE_SPAN_RANGE) { 412 start = spellCheckSpanStart + offset; 413 end = start + length; 414 } else { 415 start = spellCheckSpanStart; 416 end = spellCheckSpanEnd; 417 } 418 419 String[] suggestions = new String[suggestionsCount]; 420 for (int i = 0; i < suggestionsCount; i++) { 421 suggestions[i] = suggestionsInfo.getSuggestionAt(i); 422 } 423 424 SuggestionSpan suggestionSpan = new SuggestionSpan(mTextView.getContext(), suggestions, 425 SuggestionSpan.FLAG_EASY_CORRECT | SuggestionSpan.FLAG_MISSPELLED); 426 editable.setSpan(suggestionSpan, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 427 428 mTextView.invalidateRegion(start, end, false /* No cursor involved */); 429 } 430 431 private class SpellParser { 432 private Object mRange = new Object(); 433 434 public void parse(int start, int end) { 435 if (end > start) { 436 setRangeSpan((Editable) mTextView.getText(), start, end); 437 parse(); 438 } 439 } 440 441 public boolean isFinished() { 442 return ((Editable) mTextView.getText()).getSpanStart(mRange) < 0; 443 } 444 445 public void stop() { 446 removeRangeSpan((Editable) mTextView.getText()); 447 } 448 449 private void setRangeSpan(Editable editable, int start, int end) { 450 editable.setSpan(mRange, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 451 } 452 453 private void removeRangeSpan(Editable editable) { 454 editable.removeSpan(mRange); 455 } 456 457 public void parse() { 458 Editable editable = (Editable) mTextView.getText(); 459 // Iterate over the newly added text and schedule new SpellCheckSpans 460 final int start; 461 if (mIsSentenceSpellCheckSupported) { 462 // TODO: Find the start position of the sentence. 463 // Set span with the context 464 start = Math.max( 465 0, editable.getSpanStart(mRange) - MIN_SENTENCE_LENGTH); 466 } else { 467 start = editable.getSpanStart(mRange); 468 } 469 470 final int end = editable.getSpanEnd(mRange); 471 472 int wordIteratorWindowEnd = Math.min(end, start + WORD_ITERATOR_INTERVAL); 473 mWordIterator.setCharSequence(editable, start, wordIteratorWindowEnd); 474 475 // Move back to the beginning of the current word, if any 476 int wordStart = mWordIterator.preceding(start); 477 int wordEnd; 478 if (wordStart == BreakIterator.DONE) { 479 wordEnd = mWordIterator.following(start); 480 if (wordEnd != BreakIterator.DONE) { 481 wordStart = mWordIterator.getBeginning(wordEnd); 482 } 483 } else { 484 wordEnd = mWordIterator.getEnd(wordStart); 485 } 486 if (wordEnd == BreakIterator.DONE) { 487 removeRangeSpan(editable); 488 return; 489 } 490 491 // We need to expand by one character because we want to include the spans that 492 // end/start at position start/end respectively. 493 SpellCheckSpan[] spellCheckSpans = editable.getSpans(start - 1, end + 1, 494 SpellCheckSpan.class); 495 SuggestionSpan[] suggestionSpans = editable.getSpans(start - 1, end + 1, 496 SuggestionSpan.class); 497 498 int wordCount = 0; 499 boolean scheduleOtherSpellCheck = false; 500 501 if (mIsSentenceSpellCheckSupported) { 502 int regionEnd; 503 if (wordIteratorWindowEnd < end) { 504 // Several batches needed on that region. Cut after last previous word 505 regionEnd = mWordIterator.preceding(wordIteratorWindowEnd); 506 scheduleOtherSpellCheck = true; 507 } else { 508 regionEnd = mWordIterator.preceding(end); 509 } 510 boolean correct = regionEnd != BreakIterator.DONE; 511 if (correct) { 512 regionEnd = mWordIterator.getEnd(regionEnd); 513 correct = regionEnd != BreakIterator.DONE; 514 } 515 if (!correct) { 516 editable.removeSpan(mRange); 517 return; 518 } 519 // Stop spell checking when there are no characters in the range. 520 if (wordEnd < start) { 521 return; 522 } 523 // TODO: Find the start position of the sentence. 524 final int spellCheckStart = wordStart; 525 if (regionEnd <= spellCheckStart) { 526 return; 527 } 528 final int selectionStart = Selection.getSelectionStart(editable); 529 final int selectionEnd = Selection.getSelectionEnd(editable); 530 if (DBG) { 531 Log.d(TAG, "addSpellCheckSpan: " 532 + editable.subSequence(spellCheckStart, regionEnd) 533 + ", regionEnd = " + regionEnd + ", spellCheckStart = " 534 + spellCheckStart + ", sel start = " + selectionStart + ", sel end =" 535 + selectionEnd); 536 } 537 // Do not check this word if the user is currently editing it 538 if (spellCheckStart >= 0 && regionEnd > spellCheckStart 539 && (selectionEnd < spellCheckStart || selectionStart > regionEnd)) { 540 addSpellCheckSpan(editable, spellCheckStart, regionEnd); 541 } 542 wordStart = regionEnd; 543 } else { 544 while (wordStart <= end) { 545 if (wordEnd >= start && wordEnd > wordStart) { 546 if (wordCount >= MAX_NUMBER_OF_WORDS) { 547 scheduleOtherSpellCheck = true; 548 break; 549 } 550 // A new word has been created across the interval boundaries with this 551 // edit. The previous spans (that ended on start / started on end) are 552 // not valid anymore and must be removed. 553 if (wordStart < start && wordEnd > start) { 554 removeSpansAt(editable, start, spellCheckSpans); 555 removeSpansAt(editable, start, suggestionSpans); 556 } 557 558 if (wordStart < end && wordEnd > end) { 559 removeSpansAt(editable, end, spellCheckSpans); 560 removeSpansAt(editable, end, suggestionSpans); 561 } 562 563 // Do not create new boundary spans if they already exist 564 boolean createSpellCheckSpan = true; 565 if (wordEnd == start) { 566 for (int i = 0; i < spellCheckSpans.length; i++) { 567 final int spanEnd = editable.getSpanEnd(spellCheckSpans[i]); 568 if (spanEnd == start) { 569 createSpellCheckSpan = false; 570 break; 571 } 572 } 573 } 574 575 if (wordStart == end) { 576 for (int i = 0; i < spellCheckSpans.length; i++) { 577 final int spanStart = editable.getSpanStart(spellCheckSpans[i]); 578 if (spanStart == end) { 579 createSpellCheckSpan = false; 580 break; 581 } 582 } 583 } 584 585 if (createSpellCheckSpan) { 586 addSpellCheckSpan(editable, wordStart, wordEnd); 587 } 588 wordCount++; 589 } 590 591 // iterate word by word 592 int originalWordEnd = wordEnd; 593 wordEnd = mWordIterator.following(wordEnd); 594 if ((wordIteratorWindowEnd < end) && 595 (wordEnd == BreakIterator.DONE || wordEnd >= wordIteratorWindowEnd)) { 596 wordIteratorWindowEnd = 597 Math.min(end, originalWordEnd + WORD_ITERATOR_INTERVAL); 598 mWordIterator.setCharSequence( 599 editable, originalWordEnd, wordIteratorWindowEnd); 600 wordEnd = mWordIterator.following(originalWordEnd); 601 } 602 if (wordEnd == BreakIterator.DONE) break; 603 wordStart = mWordIterator.getBeginning(wordEnd); 604 if (wordStart == BreakIterator.DONE) { 605 break; 606 } 607 } 608 } 609 610 if (scheduleOtherSpellCheck) { 611 // Update range span: start new spell check from last wordStart 612 setRangeSpan(editable, wordStart, end); 613 } else { 614 removeRangeSpan(editable); 615 } 616 617 spellCheck(); 618 } 619 620 private <T> void removeSpansAt(Editable editable, int offset, T[] spans) { 621 final int length = spans.length; 622 for (int i = 0; i < length; i++) { 623 final T span = spans[i]; 624 final int start = editable.getSpanStart(span); 625 if (start > offset) continue; 626 final int end = editable.getSpanEnd(span); 627 if (end < offset) continue; 628 editable.removeSpan(span); 629 } 630 } 631 } 632} 633