SpellChecker.java revision f9bb1cd1fcff7079445dae494ce5d56276092c11
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.Spanned; 23import android.text.method.WordIterator; 24import android.text.style.SpellCheckSpan; 25import android.text.style.SuggestionSpan; 26import android.view.textservice.SpellCheckerSession; 27import android.view.textservice.SpellCheckerSession.SpellCheckerSessionListener; 28import android.view.textservice.SuggestionsInfo; 29import android.view.textservice.TextInfo; 30import android.view.textservice.TextServicesManager; 31 32import com.android.internal.util.ArrayUtils; 33 34import java.text.BreakIterator; 35import java.util.Locale; 36 37 38/** 39 * Helper class for TextView. Bridge between the TextView and the Dictionnary service. 40 * 41 * @hide 42 */ 43public class SpellChecker implements SpellCheckerSessionListener { 44 45 // No more than this number of words will be parsed on each iteration to ensure a minimum 46 // lock of the UI thread 47 public static final int MAX_NUMBER_OF_WORDS = 10; 48 49 // Safe estimate, will ensure that the interval below usually does not have to be updated 50 public static final int AVERAGE_WORD_LENGTH = 10; 51 52 // When parsing, use a character window of that size. Will be shifted if needed 53 public static final int WORD_ITERATOR_INTERVAL = AVERAGE_WORD_LENGTH * MAX_NUMBER_OF_WORDS; 54 55 private final static int SPELL_PAUSE_DURATION = 400; // milliseconds 56 57 private final TextView mTextView; 58 59 SpellCheckerSession mSpellCheckerSession; 60 final int mCookie; 61 62 // Paired arrays for the (id, spellCheckSpan) pair. A negative id means the associated 63 // SpellCheckSpan has been recycled and can be-reused. 64 // Contains null SpellCheckSpans after index mLength. 65 private int[] mIds; 66 private SpellCheckSpan[] mSpellCheckSpans; 67 // The mLength first elements of the above arrays have been initialized 68 private int mLength; 69 70 // Parsers on chunck of text, cutting text into words that will be checked 71 private SpellParser[] mSpellParsers = new SpellParser[0]; 72 73 private int mSpanSequenceCounter = 0; 74 75 private Locale mCurrentLocale; 76 77 public SpellChecker(TextView textView) { 78 mTextView = textView; 79 80 // Arbitrary: these arrays will automatically double their sizes on demand 81 final int size = ArrayUtils.idealObjectArraySize(1); 82 mIds = new int[size]; 83 mSpellCheckSpans = new SpellCheckSpan[size]; 84 85 setLocale(mTextView.getTextServicesLocale()); 86 87 mCookie = hashCode(); 88 } 89 90 private void setLocale(Locale locale) { 91 closeSession(); 92 final TextServicesManager textServicesManager = (TextServicesManager) 93 mTextView.getContext().getSystemService(Context.TEXT_SERVICES_MANAGER_SERVICE); 94 if (!textServicesManager.isSpellCheckerEnabled()) { 95 mSpellCheckerSession = null; 96 } else { 97 mSpellCheckerSession = textServicesManager.newSpellCheckerSession( 98 null /* Bundle not currently used by the textServicesManager */, 99 locale, this, 100 false /* means any available languages from current spell checker */); 101 } 102 mCurrentLocale = locale; 103 104 // Restore SpellCheckSpans in pool 105 for (int i = 0; i < mLength; i++) { 106 mSpellCheckSpans[i].setSpellCheckInProgress(false); 107 mIds[i] = -1; 108 } 109 mLength = 0; 110 111 mSpellParsers = new SpellParser[0]; 112 113 // This class is the global listener for locale change: warn other locale-aware objects 114 mTextView.onLocaleChanged(); 115 } 116 117 /** 118 * @return true if a spell checker session has successfully been created. Returns false if not, 119 * for instance when spell checking has been disabled in settings. 120 */ 121 private boolean isSessionActive() { 122 return mSpellCheckerSession != null; 123 } 124 125 public void closeSession() { 126 if (mSpellCheckerSession != null) { 127 mSpellCheckerSession.close(); 128 } 129 130 stopAllSpellParsers(); 131 } 132 133 private void stopAllSpellParsers() { 134 final int length = mSpellParsers.length; 135 for (int i = 0; i < length; i++) { 136 mSpellParsers[i].stop(); 137 } 138 } 139 140 private int nextSpellCheckSpanIndex() { 141 for (int i = 0; i < mLength; i++) { 142 if (mIds[i] < 0) return i; 143 } 144 145 if (mLength == mSpellCheckSpans.length) { 146 final int newSize = mLength * 2; 147 int[] newIds = new int[newSize]; 148 SpellCheckSpan[] newSpellCheckSpans = new SpellCheckSpan[newSize]; 149 System.arraycopy(mIds, 0, newIds, 0, mLength); 150 System.arraycopy(mSpellCheckSpans, 0, newSpellCheckSpans, 0, mLength); 151 mIds = newIds; 152 mSpellCheckSpans = newSpellCheckSpans; 153 } 154 155 mSpellCheckSpans[mLength] = new SpellCheckSpan(); 156 mLength++; 157 return mLength - 1; 158 } 159 160 private void addSpellCheckSpan(Editable editable, int start, int end) { 161 final int index = nextSpellCheckSpanIndex(); 162 editable.setSpan(mSpellCheckSpans[index], start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 163 mIds[index] = mSpanSequenceCounter++; 164 } 165 166 public void removeSpellCheckSpan(SpellCheckSpan spellCheckSpan) { 167 for (int i = 0; i < mLength; i++) { 168 if (mSpellCheckSpans[i] == spellCheckSpan) { 169 mSpellCheckSpans[i].setSpellCheckInProgress(false); 170 mIds[i] = -1; 171 return; 172 } 173 } 174 } 175 176 public void onSelectionChanged() { 177 spellCheck(); 178 } 179 180 public void spellCheck(int start, int end) { 181 final Locale locale = mTextView.getTextServicesLocale(); 182 if (mCurrentLocale == null || (!(mCurrentLocale.equals(locale)))) { 183 setLocale(locale); 184 // Re-check the entire text 185 start = 0; 186 end = mTextView.getText().length(); 187 } 188 189 if (!isSessionActive()) return; 190 191 // Find first available SpellParser from pool 192 final int length = mSpellParsers.length; 193 for (int i = 0; i < length; i++) { 194 final SpellParser spellParser = mSpellParsers[i]; 195 if (!spellParser.isParsing()) { 196 spellParser.init(start, end); 197 spellParser.parse(); 198 return; 199 } 200 } 201 202 // No available parser found in pool, create a new one 203 SpellParser[] newSpellParsers = new SpellParser[length + 1]; 204 System.arraycopy(mSpellParsers, 0, newSpellParsers, 0, length); 205 mSpellParsers = newSpellParsers; 206 207 SpellParser spellParser = new SpellParser(); 208 mSpellParsers[length] = spellParser; 209 spellParser.init(start, end); 210 spellParser.parse(); 211 } 212 213 private void spellCheck() { 214 if (mSpellCheckerSession == null) return; 215 216 Editable editable = (Editable) mTextView.getText(); 217 final int selectionStart = Selection.getSelectionStart(editable); 218 final int selectionEnd = Selection.getSelectionEnd(editable); 219 220 TextInfo[] textInfos = new TextInfo[mLength]; 221 int textInfosCount = 0; 222 223 final String text = editable.toString(); 224 for (int i = 0; i < mLength; i++) { 225 final SpellCheckSpan spellCheckSpan = mSpellCheckSpans[i]; 226 if (spellCheckSpan.isSpellCheckInProgress()) continue; 227 228 final int start = editable.getSpanStart(spellCheckSpan); 229 final int end = editable.getSpanEnd(spellCheckSpan); 230 231 // Do not check this word if the user is currently editing it 232 if (start >= 0 && end > start && (selectionEnd < start || selectionStart > end)) { 233 final String word = text.substring(start, end); 234 spellCheckSpan.setSpellCheckInProgress(true); 235 textInfos[textInfosCount++] = new TextInfo(word, mCookie, mIds[i]); 236 } 237 } 238 239 if (textInfosCount > 0) { 240 if (textInfosCount < textInfos.length) { 241 TextInfo[] textInfosCopy = new TextInfo[textInfosCount]; 242 System.arraycopy(textInfos, 0, textInfosCopy, 0, textInfosCount); 243 textInfos = textInfosCopy; 244 } 245 246 mSpellCheckerSession.getSuggestions(textInfos, SuggestionSpan.SUGGESTIONS_MAX_SIZE, 247 false /* TODO Set sequentialWords to true for initial spell check */); 248 } 249 } 250 251 @Override 252 public void onGetSuggestionsForSentence(SuggestionsInfo[] results) { 253 // TODO: Handle the position and length for each suggestion 254 onGetSuggestions(results); 255 } 256 257 @Override 258 public void onGetSuggestions(SuggestionsInfo[] results) { 259 Editable editable = (Editable) mTextView.getText(); 260 261 for (int i = 0; i < results.length; i++) { 262 SuggestionsInfo suggestionsInfo = results[i]; 263 if (suggestionsInfo.getCookie() != mCookie) continue; 264 final int sequenceNumber = suggestionsInfo.getSequence(); 265 266 for (int j = 0; j < mLength; j++) { 267 if (sequenceNumber == mIds[j]) { 268 final int attributes = suggestionsInfo.getSuggestionsAttributes(); 269 boolean isInDictionary = 270 ((attributes & SuggestionsInfo.RESULT_ATTR_IN_THE_DICTIONARY) > 0); 271 boolean looksLikeTypo = 272 ((attributes & SuggestionsInfo.RESULT_ATTR_LOOKS_LIKE_TYPO) > 0); 273 274 SpellCheckSpan spellCheckSpan = mSpellCheckSpans[j]; 275 276 if (!isInDictionary && looksLikeTypo) { 277 createMisspelledSuggestionSpan(editable, suggestionsInfo, spellCheckSpan); 278 } 279 280 editable.removeSpan(spellCheckSpan); 281 break; 282 } 283 } 284 } 285 286 mTextView.postDelayed(new Runnable() { 287 @Override 288 public void run() { 289 final int length = mSpellParsers.length; 290 for (int i = 0; i < length; i++) { 291 final SpellParser spellParser = mSpellParsers[i]; 292 if (spellParser.isParsing()) { 293 spellParser.parse(); 294 } 295 } 296 } 297 }, SPELL_PAUSE_DURATION); 298 } 299 300 private void createMisspelledSuggestionSpan(Editable editable, SuggestionsInfo suggestionsInfo, 301 SpellCheckSpan spellCheckSpan) { 302 final int start = editable.getSpanStart(spellCheckSpan); 303 final int end = editable.getSpanEnd(spellCheckSpan); 304 if (start < 0 || end <= start) return; // span was removed in the meantime 305 306 // Other suggestion spans may exist on that region, with identical suggestions, filter 307 // them out to avoid duplicates. 308 SuggestionSpan[] suggestionSpans = editable.getSpans(start, end, SuggestionSpan.class); 309 final int length = suggestionSpans.length; 310 for (int i = 0; i < length; i++) { 311 final int spanStart = editable.getSpanStart(suggestionSpans[i]); 312 final int spanEnd = editable.getSpanEnd(suggestionSpans[i]); 313 if (spanStart != start || spanEnd != end) { 314 // Nulled (to avoid new array allocation) if not on that exact same region 315 suggestionSpans[i] = null; 316 } 317 } 318 319 final int suggestionsCount = suggestionsInfo.getSuggestionsCount(); 320 String[] suggestions; 321 if (suggestionsCount <= 0) { 322 // A negative suggestion count is possible 323 suggestions = ArrayUtils.emptyArray(String.class); 324 } else { 325 int numberOfSuggestions = 0; 326 suggestions = new String[suggestionsCount]; 327 328 for (int i = 0; i < suggestionsCount; i++) { 329 final String spellSuggestion = suggestionsInfo.getSuggestionAt(i); 330 if (spellSuggestion == null) break; 331 boolean suggestionFound = false; 332 333 for (int j = 0; j < length && !suggestionFound; j++) { 334 if (suggestionSpans[j] == null) break; 335 336 String[] suggests = suggestionSpans[j].getSuggestions(); 337 for (int k = 0; k < suggests.length; k++) { 338 if (spellSuggestion.equals(suggests[k])) { 339 // The suggestion is already provided by an other SuggestionSpan 340 suggestionFound = true; 341 break; 342 } 343 } 344 } 345 346 if (!suggestionFound) { 347 suggestions[numberOfSuggestions++] = spellSuggestion; 348 } 349 } 350 351 if (numberOfSuggestions != suggestionsCount) { 352 String[] newSuggestions = new String[numberOfSuggestions]; 353 System.arraycopy(suggestions, 0, newSuggestions, 0, numberOfSuggestions); 354 suggestions = newSuggestions; 355 } 356 } 357 358 SuggestionSpan suggestionSpan = new SuggestionSpan(mTextView.getContext(), suggestions, 359 SuggestionSpan.FLAG_EASY_CORRECT | SuggestionSpan.FLAG_MISSPELLED); 360 editable.setSpan(suggestionSpan, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 361 362 mTextView.invalidateRegion(start, end); 363 } 364 365 private class SpellParser { 366 private Object mRange = new Object(); 367 368 public void init(int start, int end) { 369 setRangeSpan((Editable) mTextView.getText(), start, end); 370 } 371 372 public void stop() { 373 removeRangeSpan((Editable) mTextView.getText()); 374 } 375 376 public boolean isParsing() { 377 return ((Editable) mTextView.getText()).getSpanStart(mRange) >= 0; 378 } 379 380 private void setRangeSpan(Editable editable, int start, int end) { 381 editable.setSpan(mRange, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 382 } 383 384 private void removeRangeSpan(Editable editable) { 385 editable.removeSpan(mRange); 386 } 387 388 public void parse() { 389 Editable editable = (Editable) mTextView.getText(); 390 // Iterate over the newly added text and schedule new SpellCheckSpans 391 final int start = editable.getSpanStart(mRange); 392 final int end = editable.getSpanEnd(mRange); 393 394 final WordIterator wordIterator = mTextView.getWordIterator(); 395 int wordIteratorWindowEnd = Math.min(end, start + WORD_ITERATOR_INTERVAL); 396 wordIterator.setCharSequence(editable, start, wordIteratorWindowEnd); 397 398 // Move back to the beginning of the current word, if any 399 int wordStart = wordIterator.preceding(start); 400 int wordEnd; 401 if (wordStart == BreakIterator.DONE) { 402 wordEnd = wordIterator.following(start); 403 if (wordEnd != BreakIterator.DONE) { 404 wordStart = wordIterator.getBeginning(wordEnd); 405 } 406 } else { 407 wordEnd = wordIterator.getEnd(wordStart); 408 } 409 if (wordEnd == BreakIterator.DONE) { 410 removeRangeSpan(editable); 411 return; 412 } 413 414 // We need to expand by one character because we want to include the spans that 415 // end/start at position start/end respectively. 416 SpellCheckSpan[] spellCheckSpans = editable.getSpans(start - 1, end + 1, 417 SpellCheckSpan.class); 418 SuggestionSpan[] suggestionSpans = editable.getSpans(start - 1, end + 1, 419 SuggestionSpan.class); 420 421 int wordCount = 0; 422 boolean scheduleOtherSpellCheck = false; 423 424 while (wordStart <= end) { 425 if (wordEnd >= start && wordEnd > wordStart) { 426 if (wordCount >= MAX_NUMBER_OF_WORDS) { 427 scheduleOtherSpellCheck = true; 428 break; 429 } 430 431 // A new word has been created across the interval boundaries with this edit. 432 // Previous spans (ended on start / started on end) removed, not valid anymore 433 if (wordStart < start && wordEnd > start) { 434 removeSpansAt(editable, start, spellCheckSpans); 435 removeSpansAt(editable, start, suggestionSpans); 436 } 437 438 if (wordStart < end && wordEnd > end) { 439 removeSpansAt(editable, end, spellCheckSpans); 440 removeSpansAt(editable, end, suggestionSpans); 441 } 442 443 // Do not create new boundary spans if they already exist 444 boolean createSpellCheckSpan = true; 445 if (wordEnd == start) { 446 for (int i = 0; i < spellCheckSpans.length; i++) { 447 final int spanEnd = editable.getSpanEnd(spellCheckSpans[i]); 448 if (spanEnd == start) { 449 createSpellCheckSpan = false; 450 break; 451 } 452 } 453 } 454 455 if (wordStart == end) { 456 for (int i = 0; i < spellCheckSpans.length; i++) { 457 final int spanStart = editable.getSpanStart(spellCheckSpans[i]); 458 if (spanStart == end) { 459 createSpellCheckSpan = false; 460 break; 461 } 462 } 463 } 464 465 if (createSpellCheckSpan) { 466 addSpellCheckSpan(editable, wordStart, wordEnd); 467 } 468 wordCount++; 469 } 470 471 // iterate word by word 472 int originalWordEnd = wordEnd; 473 wordEnd = wordIterator.following(wordEnd); 474 if ((wordIteratorWindowEnd < end) && 475 (wordEnd == BreakIterator.DONE || wordEnd >= wordIteratorWindowEnd)) { 476 wordIteratorWindowEnd = Math.min(end, originalWordEnd + WORD_ITERATOR_INTERVAL); 477 wordIterator.setCharSequence(editable, originalWordEnd, wordIteratorWindowEnd); 478 wordEnd = wordIterator.following(originalWordEnd); 479 } 480 if (wordEnd == BreakIterator.DONE) break; 481 wordStart = wordIterator.getBeginning(wordEnd); 482 if (wordStart == BreakIterator.DONE) { 483 break; 484 } 485 } 486 487 if (scheduleOtherSpellCheck) { 488 // Update range span: start new spell check from last wordStart 489 setRangeSpan(editable, wordStart, end); 490 } else { 491 removeRangeSpan(editable); 492 } 493 494 spellCheck(); 495 } 496 497 private <T> void removeSpansAt(Editable editable, int offset, T[] spans) { 498 final int length = spans.length; 499 for (int i = 0; i < length; i++) { 500 final T span = spans[i]; 501 final int start = editable.getSpanStart(span); 502 if (start > offset) continue; 503 final int end = editable.getSpanEnd(span); 504 if (end < offset) continue; 505 editable.removeSpan(span); 506 } 507 } 508 } 509} 510