SpellChecker.java revision c1761e7fe10390d90b805f373b51ecaabf214dac
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.view.textservice.SpellCheckerSession; 28import android.view.textservice.SpellCheckerSession.SpellCheckerSessionListener; 29import android.view.textservice.SuggestionsInfo; 30import android.view.textservice.TextInfo; 31import android.view.textservice.TextServicesManager; 32 33import com.android.internal.util.ArrayUtils; 34 35import java.text.BreakIterator; 36import java.util.Locale; 37 38 39/** 40 * Helper class for TextView. Bridge between the TextView and the Dictionnary service. 41 * 42 * @hide 43 */ 44public class SpellChecker implements SpellCheckerSessionListener { 45 46 // No more than this number of words will be parsed on each iteration to ensure a minimum 47 // lock of the UI thread 48 public static final int MAX_NUMBER_OF_WORDS = 50; 49 50 // Rough estimate, such that the word iterator interval usually does not need to be shifted 51 public static final int AVERAGE_WORD_LENGTH = 7; 52 53 // When parsing, use a character window of that size. Will be shifted if needed 54 public static final int WORD_ITERATOR_INTERVAL = AVERAGE_WORD_LENGTH * MAX_NUMBER_OF_WORDS; 55 56 // Pause between each spell check to keep the UI smooth 57 private final static int SPELL_PAUSE_DURATION = 400; // milliseconds 58 59 private final TextView mTextView; 60 61 SpellCheckerSession mSpellCheckerSession; 62 final int mCookie; 63 64 // Paired arrays for the (id, spellCheckSpan) pair. A negative id means the associated 65 // SpellCheckSpan has been recycled and can be-reused. 66 // Contains null SpellCheckSpans after index mLength. 67 private int[] mIds; 68 private SpellCheckSpan[] mSpellCheckSpans; 69 // The mLength first elements of the above arrays have been initialized 70 private int mLength; 71 72 // Parsers on chunck of text, cutting text into words that will be checked 73 private SpellParser[] mSpellParsers = new SpellParser[0]; 74 75 private int mSpanSequenceCounter = 0; 76 77 private Locale mCurrentLocale; 78 79 // Shared by all SpellParsers. Cannot be shared with TextView since it may be used 80 // concurrently due to the asynchronous nature of onGetSuggestions. 81 private WordIterator mWordIterator; 82 83 private TextServicesManager mTextServicesManager; 84 85 private Runnable mSpellRunnable; 86 87 public SpellChecker(TextView textView) { 88 mTextView = textView; 89 90 // Arbitrary: these arrays will automatically double their sizes on demand 91 final int size = ArrayUtils.idealObjectArraySize(1); 92 mIds = new int[size]; 93 mSpellCheckSpans = new SpellCheckSpan[size]; 94 95 setLocale(mTextView.getTextServicesLocale()); 96 97 mCookie = hashCode(); 98 } 99 100 private void setLocale(Locale locale) { 101 closeSession(); 102 final TextServicesManager textServicesManager = (TextServicesManager) 103 mTextView.getContext().getSystemService(Context.TEXT_SERVICES_MANAGER_SERVICE); 104 if (!textServicesManager.isSpellCheckerEnabled()) { 105 mSpellCheckerSession = null; 106 } else { 107 mSpellCheckerSession = textServicesManager.newSpellCheckerSession( 108 null /* Bundle not currently used by the textServicesManager */, 109 locale, this, 110 false /* means any available languages from current spell checker */); 111 } 112 mCurrentLocale = locale; 113 114 // Restore SpellCheckSpans in pool 115 for (int i = 0; i < mLength; i++) { 116 mSpellCheckSpans[i].setSpellCheckInProgress(false); 117 mIds[i] = -1; 118 } 119 mLength = 0; 120 121 mSpellParsers = new SpellParser[0]; 122 123 // This class is the global listener for locale change: warn other locale-aware objects 124 mTextView.onLocaleChanged(); 125 } 126 127 /** 128 * @return true if a spell checker session has successfully been created. Returns false if not, 129 * for instance when spell checking has been disabled in settings. 130 */ 131 private boolean isSessionActive() { 132 return mSpellCheckerSession != null; 133 } 134 135 public void closeSession() { 136 if (mSpellCheckerSession != null) { 137 mSpellCheckerSession.close(); 138 } 139 140 stopAllSpellParsers(); 141 } 142 143 private void stopAllSpellParsers() { 144 final int length = mSpellParsers.length; 145 for (int i = 0; i < length; i++) { 146 mSpellParsers[i].stop(); 147 } 148 149 if (mSpellRunnable != null) { 150 mTextView.removeCallbacks(mSpellRunnable); 151 } 152 } 153 154 private int nextSpellCheckSpanIndex() { 155 for (int i = 0; i < mLength; i++) { 156 if (mIds[i] < 0) return i; 157 } 158 159 if (mLength == mSpellCheckSpans.length) { 160 final int newSize = mLength * 2; 161 int[] newIds = new int[newSize]; 162 SpellCheckSpan[] newSpellCheckSpans = new SpellCheckSpan[newSize]; 163 System.arraycopy(mIds, 0, newIds, 0, mLength); 164 System.arraycopy(mSpellCheckSpans, 0, newSpellCheckSpans, 0, mLength); 165 mIds = newIds; 166 mSpellCheckSpans = newSpellCheckSpans; 167 } 168 169 mSpellCheckSpans[mLength] = new SpellCheckSpan(); 170 mLength++; 171 return mLength - 1; 172 } 173 174 private void addSpellCheckSpan(Editable editable, int start, int end) { 175 final int index = nextSpellCheckSpanIndex(); 176 editable.setSpan(mSpellCheckSpans[index], start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 177 mIds[index] = mSpanSequenceCounter++; 178 } 179 180 public void removeSpellCheckSpan(SpellCheckSpan spellCheckSpan) { 181 for (int i = 0; i < mLength; i++) { 182 if (mSpellCheckSpans[i] == spellCheckSpan) { 183 mSpellCheckSpans[i].setSpellCheckInProgress(false); 184 mIds[i] = -1; 185 return; 186 } 187 } 188 } 189 190 public void onSelectionChanged() { 191 spellCheck(); 192 } 193 194 public void spellCheck(int start, int end) { 195 final Locale locale = mTextView.getTextServicesLocale(); 196 if (mCurrentLocale == null || (!(mCurrentLocale.equals(locale)))) { 197 setLocale(locale); 198 // Re-check the entire text 199 start = 0; 200 end = mTextView.getText().length(); 201 } 202 203 if (!isSessionActive()) return; 204 205 // Find first available SpellParser from pool 206 final int length = mSpellParsers.length; 207 for (int i = 0; i < length; i++) { 208 final SpellParser spellParser = mSpellParsers[i]; 209 if (!spellParser.isParsing()) { 210 spellParser.init(start, end); 211 spellParser.parse(); 212 return; 213 } 214 } 215 216 // No available parser found in pool, create a new one 217 SpellParser[] newSpellParsers = new SpellParser[length + 1]; 218 System.arraycopy(mSpellParsers, 0, newSpellParsers, 0, length); 219 mSpellParsers = newSpellParsers; 220 221 SpellParser spellParser = new SpellParser(); 222 mSpellParsers[length] = spellParser; 223 spellParser.init(start, end); 224 spellParser.parse(); 225 } 226 227 private void spellCheck() { 228 if (mSpellCheckerSession == null) return; 229 230 Editable editable = (Editable) mTextView.getText(); 231 final int selectionStart = Selection.getSelectionStart(editable); 232 final int selectionEnd = Selection.getSelectionEnd(editable); 233 234 TextInfo[] textInfos = new TextInfo[mLength]; 235 int textInfosCount = 0; 236 237 for (int i = 0; i < mLength; i++) { 238 final SpellCheckSpan spellCheckSpan = mSpellCheckSpans[i]; 239 if (spellCheckSpan.isSpellCheckInProgress()) continue; 240 241 final int start = editable.getSpanStart(spellCheckSpan); 242 final int end = editable.getSpanEnd(spellCheckSpan); 243 244 // Do not check this word if the user is currently editing it 245 if (start >= 0 && end > start && (selectionEnd < start || selectionStart > end)) { 246 final String word = (editable instanceof SpannableStringBuilder) ? 247 ((SpannableStringBuilder) editable).substring(start, end) : 248 editable.subSequence(start, end).toString(); 249 spellCheckSpan.setSpellCheckInProgress(true); 250 textInfos[textInfosCount++] = new TextInfo(word, mCookie, mIds[i]); 251 } 252 } 253 254 if (textInfosCount > 0) { 255 if (textInfosCount < textInfos.length) { 256 TextInfo[] textInfosCopy = new TextInfo[textInfosCount]; 257 System.arraycopy(textInfos, 0, textInfosCopy, 0, textInfosCount); 258 textInfos = textInfosCopy; 259 } 260 261 mSpellCheckerSession.getSuggestions(textInfos, SuggestionSpan.SUGGESTIONS_MAX_SIZE, 262 false /* TODO Set sequentialWords to true for initial spell check */); 263 } 264 } 265 266 @Override 267 public void onGetSuggestionsForSentence(SuggestionsInfo[] results) { 268 // TODO: Handle the position and length for each suggestion 269 onGetSuggestions(results); 270 } 271 272 @Override 273 public void onGetSuggestions(SuggestionsInfo[] results) { 274 Editable editable = (Editable) mTextView.getText(); 275 276 for (int i = 0; i < results.length; i++) { 277 SuggestionsInfo suggestionsInfo = results[i]; 278 if (suggestionsInfo.getCookie() != mCookie) continue; 279 final int sequenceNumber = suggestionsInfo.getSequence(); 280 281 for (int j = 0; j < mLength; j++) { 282 if (sequenceNumber == mIds[j]) { 283 final int attributes = suggestionsInfo.getSuggestionsAttributes(); 284 boolean isInDictionary = 285 ((attributes & SuggestionsInfo.RESULT_ATTR_IN_THE_DICTIONARY) > 0); 286 boolean looksLikeTypo = 287 ((attributes & SuggestionsInfo.RESULT_ATTR_LOOKS_LIKE_TYPO) > 0); 288 289 SpellCheckSpan spellCheckSpan = mSpellCheckSpans[j]; 290 291 if (!isInDictionary && looksLikeTypo) { 292 createMisspelledSuggestionSpan(editable, suggestionsInfo, spellCheckSpan); 293 } 294 295 editable.removeSpan(spellCheckSpan); 296 break; 297 } 298 } 299 } 300 301 scheduleNewSpellCheck(); 302 } 303 304 private void scheduleNewSpellCheck() { 305 if (mSpellRunnable == null) { 306 mSpellRunnable = new Runnable() { 307 @Override 308 public void run() { 309 final int length = mSpellParsers.length; 310 for (int i = 0; i < length; i++) { 311 final SpellParser spellParser = mSpellParsers[i]; 312 if (!spellParser.isParsing()) { 313 spellParser.parse(); 314 break; // run one spell parser at a time to bound running time 315 } 316 } 317 } 318 }; 319 } else { 320 mTextView.removeCallbacks(mSpellRunnable); 321 } 322 323 mTextView.postDelayed(mSpellRunnable, SPELL_PAUSE_DURATION); 324 } 325 326 private void createMisspelledSuggestionSpan(Editable editable, SuggestionsInfo suggestionsInfo, 327 SpellCheckSpan spellCheckSpan) { 328 final int start = editable.getSpanStart(spellCheckSpan); 329 final int end = editable.getSpanEnd(spellCheckSpan); 330 if (start < 0 || end <= start) return; // span was removed in the meantime 331 332 // Other suggestion spans may exist on that region, with identical suggestions, filter 333 // them out to avoid duplicates. 334 SuggestionSpan[] suggestionSpans = editable.getSpans(start, end, SuggestionSpan.class); 335 final int length = suggestionSpans.length; 336 for (int i = 0; i < length; i++) { 337 final int spanStart = editable.getSpanStart(suggestionSpans[i]); 338 final int spanEnd = editable.getSpanEnd(suggestionSpans[i]); 339 if (spanStart != start || spanEnd != end) { 340 // Nulled (to avoid new array allocation) if not on that exact same region 341 suggestionSpans[i] = null; 342 } 343 } 344 345 final int suggestionsCount = suggestionsInfo.getSuggestionsCount(); 346 String[] suggestions; 347 if (suggestionsCount <= 0) { 348 // A negative suggestion count is possible 349 suggestions = ArrayUtils.emptyArray(String.class); 350 } else { 351 int numberOfSuggestions = 0; 352 suggestions = new String[suggestionsCount]; 353 354 for (int i = 0; i < suggestionsCount; i++) { 355 final String spellSuggestion = suggestionsInfo.getSuggestionAt(i); 356 if (spellSuggestion == null) break; 357 boolean suggestionFound = false; 358 359 for (int j = 0; j < length && !suggestionFound; j++) { 360 if (suggestionSpans[j] == null) break; 361 362 String[] suggests = suggestionSpans[j].getSuggestions(); 363 for (int k = 0; k < suggests.length; k++) { 364 if (spellSuggestion.equals(suggests[k])) { 365 // The suggestion is already provided by an other SuggestionSpan 366 suggestionFound = true; 367 break; 368 } 369 } 370 } 371 372 if (!suggestionFound) { 373 suggestions[numberOfSuggestions++] = spellSuggestion; 374 } 375 } 376 377 if (numberOfSuggestions != suggestionsCount) { 378 String[] newSuggestions = new String[numberOfSuggestions]; 379 System.arraycopy(suggestions, 0, newSuggestions, 0, numberOfSuggestions); 380 suggestions = newSuggestions; 381 } 382 } 383 384 SuggestionSpan suggestionSpan = new SuggestionSpan(mTextView.getContext(), suggestions, 385 SuggestionSpan.FLAG_EASY_CORRECT | SuggestionSpan.FLAG_MISSPELLED); 386 editable.setSpan(suggestionSpan, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 387 388 mTextView.invalidateRegion(start, end); 389 } 390 391 private class SpellParser { 392 private Object mRange = new Object(); 393 394 public void init(int start, int end) { 395 setRangeSpan((Editable) mTextView.getText(), start, end); 396 } 397 398 public void stop() { 399 removeRangeSpan((Editable) mTextView.getText()); 400 } 401 402 public boolean isParsing() { 403 return ((Editable) mTextView.getText()).getSpanStart(mRange) >= 0; 404 } 405 406 private void setRangeSpan(Editable editable, int start, int end) { 407 editable.setSpan(mRange, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 408 } 409 410 private void removeRangeSpan(Editable editable) { 411 editable.removeSpan(mRange); 412 } 413 414 public void parse() { 415 Editable editable = (Editable) mTextView.getText(); 416 // Iterate over the newly added text and schedule new SpellCheckSpans 417 final int start = editable.getSpanStart(mRange); 418 final int end = editable.getSpanEnd(mRange); 419 420 int wordIteratorWindowEnd = Math.min(end, start + WORD_ITERATOR_INTERVAL); 421 mWordIterator.setCharSequence(editable, start, wordIteratorWindowEnd); 422 423 // Move back to the beginning of the current word, if any 424 int wordStart = mWordIterator.preceding(start); 425 int wordEnd; 426 if (wordStart == BreakIterator.DONE) { 427 wordEnd = mWordIterator.following(start); 428 if (wordEnd != BreakIterator.DONE) { 429 wordStart = mWordIterator.getBeginning(wordEnd); 430 } 431 } else { 432 wordEnd = mWordIterator.getEnd(wordStart); 433 } 434 if (wordEnd == BreakIterator.DONE) { 435 removeRangeSpan(editable); 436 return; 437 } 438 439 // We need to expand by one character because we want to include the spans that 440 // end/start at position start/end respectively. 441 SpellCheckSpan[] spellCheckSpans = editable.getSpans(start - 1, end + 1, 442 SpellCheckSpan.class); 443 SuggestionSpan[] suggestionSpans = editable.getSpans(start - 1, end + 1, 444 SuggestionSpan.class); 445 446 int wordCount = 0; 447 boolean scheduleOtherSpellCheck = false; 448 449 while (wordStart <= end) { 450 if (wordEnd >= start && wordEnd > wordStart) { 451 if (wordCount >= MAX_NUMBER_OF_WORDS) { 452 scheduleOtherSpellCheck = true; 453 break; 454 } 455 456 // A new word has been created across the interval boundaries with this edit. 457 // Previous spans (ended on start / started on end) removed, not valid anymore 458 if (wordStart < start && wordEnd > start) { 459 removeSpansAt(editable, start, spellCheckSpans); 460 removeSpansAt(editable, start, suggestionSpans); 461 } 462 463 if (wordStart < end && wordEnd > end) { 464 removeSpansAt(editable, end, spellCheckSpans); 465 removeSpansAt(editable, end, suggestionSpans); 466 } 467 468 // Do not create new boundary spans if they already exist 469 boolean createSpellCheckSpan = true; 470 if (wordEnd == start) { 471 for (int i = 0; i < spellCheckSpans.length; i++) { 472 final int spanEnd = editable.getSpanEnd(spellCheckSpans[i]); 473 if (spanEnd == start) { 474 createSpellCheckSpan = false; 475 break; 476 } 477 } 478 } 479 480 if (wordStart == end) { 481 for (int i = 0; i < spellCheckSpans.length; i++) { 482 final int spanStart = editable.getSpanStart(spellCheckSpans[i]); 483 if (spanStart == end) { 484 createSpellCheckSpan = false; 485 break; 486 } 487 } 488 } 489 490 if (createSpellCheckSpan) { 491 addSpellCheckSpan(editable, wordStart, wordEnd); 492 } 493 wordCount++; 494 } 495 496 // iterate word by word 497 int originalWordEnd = wordEnd; 498 wordEnd = mWordIterator.following(wordEnd); 499 if ((wordIteratorWindowEnd < end) && 500 (wordEnd == BreakIterator.DONE || wordEnd >= wordIteratorWindowEnd)) { 501 wordIteratorWindowEnd = Math.min(end, originalWordEnd + WORD_ITERATOR_INTERVAL); 502 mWordIterator.setCharSequence(editable, originalWordEnd, wordIteratorWindowEnd); 503 wordEnd = mWordIterator.following(originalWordEnd); 504 } 505 if (wordEnd == BreakIterator.DONE) break; 506 wordStart = mWordIterator.getBeginning(wordEnd); 507 if (wordStart == BreakIterator.DONE) { 508 break; 509 } 510 } 511 512 if (scheduleOtherSpellCheck) { 513 // Update range span: start new spell check from last wordStart 514 setRangeSpan(editable, wordStart, end); 515 } else { 516 removeRangeSpan(editable); 517 } 518 519 spellCheck(); 520 } 521 522 private <T> void removeSpansAt(Editable editable, int offset, T[] spans) { 523 final int length = spans.length; 524 for (int i = 0; i < length; i++) { 525 final T span = spans[i]; 526 final int start = editable.getSpanStart(span); 527 if (start > offset) continue; 528 final int end = editable.getSpanEnd(span); 529 if (end < offset) continue; 530 editable.removeSpan(span); 531 } 532 } 533 } 534} 535