1 /* 2 * Copyright (C) 2008 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.speech; 18 19 import java.util.ArrayList; 20 21 import android.app.Activity; 22 import android.content.ActivityNotFoundException; 23 import android.content.BroadcastReceiver; 24 import android.content.ComponentName; 25 import android.content.Context; 26 import android.content.Intent; 27 import android.content.pm.PackageManager; 28 import android.content.pm.ResolveInfo; 29 import android.os.Bundle; 30 31 /** 32 * Constants for supporting speech recognition through starting an {@link Intent} 33 */ 34 public class RecognizerIntent { 35 /** 36 * The extra key used in an intent to the speech recognizer for voice search. Not 37 * generally to be used by developers. The system search dialog uses this, for example, 38 * to set a calling package for identification by a voice search API. If this extra 39 * is set by anyone but the system process, it should be overridden by the voice search 40 * implementation. 41 */ 42 public final static String EXTRA_CALLING_PACKAGE = "calling_package"; 43 RecognizerIntent()44 private RecognizerIntent() { 45 // Not for instantiating. 46 } 47 48 /** 49 * Starts an activity that will prompt the user for speech and send it through a 50 * speech recognizer. The results will be returned via activity results (in 51 * {@link Activity#onActivityResult}, if you start the intent using 52 * {@link Activity#startActivityForResult(Intent, int)}), or forwarded via a PendingIntent 53 * if one is provided. 54 * 55 * <p>Starting this intent with just {@link Activity#startActivity(Intent)} is not supported. 56 * You must either use {@link Activity#startActivityForResult(Intent, int)}, or provide a 57 * PendingIntent, to receive recognition results. 58 * 59 * <p>The implementation of this API is likely to stream audio to remote servers to perform 60 * speech recognition which can use a substantial amount of bandwidth. 61 * 62 * <p>Required extras: 63 * <ul> 64 * <li>{@link #EXTRA_LANGUAGE_MODEL} 65 * </ul> 66 * 67 * <p>Optional extras: 68 * <ul> 69 * <li>{@link #EXTRA_PROMPT} 70 * <li>{@link #EXTRA_LANGUAGE} 71 * <li>{@link #EXTRA_MAX_RESULTS} 72 * <li>{@link #EXTRA_RESULTS_PENDINGINTENT} 73 * <li>{@link #EXTRA_RESULTS_PENDINGINTENT_BUNDLE} 74 * </ul> 75 * 76 * <p> Result extras (returned in the result, not to be specified in the request): 77 * <ul> 78 * <li>{@link #EXTRA_RESULTS} 79 * </ul> 80 * 81 * <p>NOTE: There may not be any applications installed to handle this action, so you should 82 * make sure to catch {@link ActivityNotFoundException}. 83 */ 84 public static final String ACTION_RECOGNIZE_SPEECH = "android.speech.action.RECOGNIZE_SPEECH"; 85 86 /** 87 * Starts an activity that will prompt the user for speech, send it through a 88 * speech recognizer, and either display a web search result or trigger 89 * another type of action based on the user's speech. 90 * 91 * <p>If you want to avoid triggering any type of action besides web search, you can use 92 * the {@link #EXTRA_WEB_SEARCH_ONLY} extra. 93 * 94 * <p>Required extras: 95 * <ul> 96 * <li>{@link #EXTRA_LANGUAGE_MODEL} 97 * </ul> 98 * 99 * <p>Optional extras: 100 * <ul> 101 * <li>{@link #EXTRA_PROMPT} 102 * <li>{@link #EXTRA_LANGUAGE} 103 * <li>{@link #EXTRA_MAX_RESULTS} 104 * <li>{@link #EXTRA_PARTIAL_RESULTS} 105 * <li>{@link #EXTRA_WEB_SEARCH_ONLY} 106 * <li>{@link #EXTRA_ORIGIN} 107 * </ul> 108 * 109 * <p> Result extras (returned in the result, not to be specified in the request): 110 * <ul> 111 * <li>{@link #EXTRA_RESULTS} 112 * <li>{@link #EXTRA_CONFIDENCE_SCORES} (optional) 113 * </ul> 114 * 115 * <p>NOTE: There may not be any applications installed to handle this action, so you should 116 * make sure to catch {@link ActivityNotFoundException}. 117 */ 118 public static final String ACTION_WEB_SEARCH = "android.speech.action.WEB_SEARCH"; 119 120 /** 121 * Starts an activity that will prompt the user for speech without requiring the user's 122 * visual attention or touch input. It will send it through a speech recognizer, 123 * and either synthesize speech for a web search result or trigger 124 * another type of action based on the user's speech. 125 * 126 * This activity may be launched while device is locked in a secure mode. 127 * Special care must be taken to ensure that the voice actions that are performed while 128 * hands free cannot compromise the device's security. 129 * The activity should check the value of the {@link #EXTRA_SECURE} extra to determine 130 * whether the device has been securely locked. If so, the activity should either restrict 131 * the set of voice actions that are permitted or require some form of secure 132 * authentication before proceeding. 133 * 134 * To ensure that the activity's user interface is visible while the lock screen is showing, 135 * the activity should set the 136 * {@link android.view.WindowManager.LayoutParams#FLAG_SHOW_WHEN_LOCKED} window flag. 137 * Otherwise the activity's user interface may be hidden by the lock screen. The activity 138 * should take care not to leak private information when the device is securely locked. 139 * 140 * <p>Optional extras: 141 * <ul> 142 * <li>{@link #EXTRA_SECURE} 143 * </ul> 144 */ 145 public static final String ACTION_VOICE_SEARCH_HANDS_FREE = 146 "android.speech.action.VOICE_SEARCH_HANDS_FREE"; 147 148 /** 149 * Optional boolean to indicate that a "hands free" voice search was performed while the device 150 * was in a secure mode. An example of secure mode is when the device's screen lock is active, 151 * and it requires some form of authentication to be unlocked. 152 * 153 * When the device is securely locked, the voice search activity should either restrict 154 * the set of voice actions that are permitted, or require some form of secure authentication 155 * before proceeding. 156 */ 157 public static final String EXTRA_SECURE = "android.speech.extras.EXTRA_SECURE"; 158 159 /** 160 * The minimum length of an utterance. We will not stop recording before this amount of time. 161 * 162 * Note that it is extremely rare you'd want to specify this value in an intent. If you don't 163 * have a very good reason to change these, you should leave them as they are. Note also that 164 * certain values may cause undesired or unexpected results - use judiciously! Additionally, 165 * depending on the recognizer implementation, these values may have no effect. 166 */ 167 public static final String EXTRA_SPEECH_INPUT_MINIMUM_LENGTH_MILLIS = 168 "android.speech.extras.SPEECH_INPUT_MINIMUM_LENGTH_MILLIS"; 169 170 /** 171 * The amount of time that it should take after we stop hearing speech to consider the input 172 * complete. 173 * 174 * Note that it is extremely rare you'd want to specify this value in an intent. If 175 * you don't have a very good reason to change these, you should leave them as they are. Note 176 * also that certain values may cause undesired or unexpected results - use judiciously! 177 * Additionally, depending on the recognizer implementation, these values may have no effect. 178 */ 179 public static final String EXTRA_SPEECH_INPUT_COMPLETE_SILENCE_LENGTH_MILLIS = 180 "android.speech.extras.SPEECH_INPUT_COMPLETE_SILENCE_LENGTH_MILLIS"; 181 182 /** 183 * The amount of time that it should take after we stop hearing speech to consider the input 184 * possibly complete. This is used to prevent the endpointer cutting off during very short 185 * mid-speech pauses. 186 * 187 * Note that it is extremely rare you'd want to specify this value in an intent. If 188 * you don't have a very good reason to change these, you should leave them as they are. Note 189 * also that certain values may cause undesired or unexpected results - use judiciously! 190 * Additionally, depending on the recognizer implementation, these values may have no effect. 191 */ 192 public static final String EXTRA_SPEECH_INPUT_POSSIBLY_COMPLETE_SILENCE_LENGTH_MILLIS = 193 "android.speech.extras.SPEECH_INPUT_POSSIBLY_COMPLETE_SILENCE_LENGTH_MILLIS"; 194 195 /** 196 * Informs the recognizer which speech model to prefer when performing 197 * {@link #ACTION_RECOGNIZE_SPEECH}. The recognizer uses this 198 * information to fine tune the results. This extra is required. Activities implementing 199 * {@link #ACTION_RECOGNIZE_SPEECH} may interpret the values as they see fit. 200 * 201 * @see #LANGUAGE_MODEL_FREE_FORM 202 * @see #LANGUAGE_MODEL_WEB_SEARCH 203 */ 204 public static final String EXTRA_LANGUAGE_MODEL = "android.speech.extra.LANGUAGE_MODEL"; 205 206 /** 207 * Use a language model based on free-form speech recognition. This is a value to use for 208 * {@link #EXTRA_LANGUAGE_MODEL}. 209 * @see #EXTRA_LANGUAGE_MODEL 210 */ 211 public static final String LANGUAGE_MODEL_FREE_FORM = "free_form"; 212 /** 213 * Use a language model based on web search terms. This is a value to use for 214 * {@link #EXTRA_LANGUAGE_MODEL}. 215 * @see #EXTRA_LANGUAGE_MODEL 216 */ 217 public static final String LANGUAGE_MODEL_WEB_SEARCH = "web_search"; 218 219 /** Optional text prompt to show to the user when asking them to speak. */ 220 public static final String EXTRA_PROMPT = "android.speech.extra.PROMPT"; 221 222 /** 223 * Optional IETF language tag (as defined by BCP 47), for example "en-US". This tag informs the 224 * recognizer to perform speech recognition in a language different than the one set in the 225 * {@link java.util.Locale#getDefault()}. 226 */ 227 public static final String EXTRA_LANGUAGE = "android.speech.extra.LANGUAGE"; 228 229 /** 230 * Optional value which can be used to indicate the referer url of a page in which 231 * speech was requested. For example, a web browser may choose to provide this for 232 * uses of speech on a given page. 233 */ 234 public static final String EXTRA_ORIGIN = "android.speech.extra.ORIGIN"; 235 236 /** 237 * Optional limit on the maximum number of results to return. If omitted the recognizer 238 * will choose how many results to return. Must be an integer. 239 */ 240 public static final String EXTRA_MAX_RESULTS = "android.speech.extra.MAX_RESULTS"; 241 242 /** 243 * Optional boolean, to be used with {@link #ACTION_WEB_SEARCH}, to indicate whether to 244 * only fire web searches in response to a user's speech. The default is false, meaning 245 * that other types of actions can be taken based on the user's speech. 246 */ 247 public static final String EXTRA_WEB_SEARCH_ONLY = "android.speech.extra.WEB_SEARCH_ONLY"; 248 249 /** 250 * Optional boolean to indicate whether partial results should be returned by the recognizer 251 * as the user speaks (default is false). The server may ignore a request for partial 252 * results in some or all cases. 253 */ 254 public static final String EXTRA_PARTIAL_RESULTS = "android.speech.extra.PARTIAL_RESULTS"; 255 256 /** 257 * When the intent is {@link #ACTION_RECOGNIZE_SPEECH}, the speech input activity will 258 * return results to you via the activity results mechanism. Alternatively, if you use this 259 * extra to supply a PendingIntent, the results will be added to its bundle and the 260 * PendingIntent will be sent to its target. 261 */ 262 public static final String EXTRA_RESULTS_PENDINGINTENT = 263 "android.speech.extra.RESULTS_PENDINGINTENT"; 264 265 /** 266 * If you use {@link #EXTRA_RESULTS_PENDINGINTENT} to supply a forwarding intent, you can 267 * also use this extra to supply additional extras for the final intent. The search results 268 * will be added to this bundle, and the combined bundle will be sent to the target. 269 */ 270 public static final String EXTRA_RESULTS_PENDINGINTENT_BUNDLE = 271 "android.speech.extra.RESULTS_PENDINGINTENT_BUNDLE"; 272 273 /** Result code returned when no matches are found for the given speech */ 274 public static final int RESULT_NO_MATCH = Activity.RESULT_FIRST_USER; 275 /** Result code returned when there is a generic client error */ 276 public static final int RESULT_CLIENT_ERROR = Activity.RESULT_FIRST_USER + 1; 277 /** Result code returned when the recognition server returns an error */ 278 public static final int RESULT_SERVER_ERROR = Activity.RESULT_FIRST_USER + 2; 279 /** Result code returned when a network error was encountered */ 280 public static final int RESULT_NETWORK_ERROR = Activity.RESULT_FIRST_USER + 3; 281 /** Result code returned when an audio error was encountered */ 282 public static final int RESULT_AUDIO_ERROR = Activity.RESULT_FIRST_USER + 4; 283 284 /** 285 * An ArrayList<String> of the recognition results when performing 286 * {@link #ACTION_RECOGNIZE_SPEECH}. Generally this list should be ordered in 287 * descending order of speech recognizer confidence. (See {@link #EXTRA_CONFIDENCE_SCORES}). 288 * Returned in the results; not to be specified in the recognition request. Only present 289 * when {@link Activity#RESULT_OK} is returned in an activity result. In a PendingIntent, 290 * the lack of this extra indicates failure. 291 */ 292 public static final String EXTRA_RESULTS = "android.speech.extra.RESULTS"; 293 294 /** 295 * A float array of confidence scores of the recognition results when performing 296 * {@link #ACTION_RECOGNIZE_SPEECH}. The array should be the same size as the ArrayList 297 * returned in {@link #EXTRA_RESULTS}, and should contain values ranging from 0.0 to 1.0, 298 * or -1 to represent an unavailable confidence score. 299 * <p> 300 * Confidence values close to 1.0 indicate high confidence (the speech recognizer is 301 * confident that the recognition result is correct), while values close to 0.0 indicate 302 * low confidence. 303 * <p> 304 * Returned in the results; not to be specified in the recognition request. This extra is 305 * optional and might not be provided. Only present when {@link Activity#RESULT_OK} is 306 * returned in an activity result. 307 */ 308 public static final String EXTRA_CONFIDENCE_SCORES = "android.speech.extra.CONFIDENCE_SCORES"; 309 310 /** 311 * Returns the broadcast intent to fire with 312 * {@link Context#sendOrderedBroadcast(Intent, String, BroadcastReceiver, android.os.Handler, int, String, Bundle)} 313 * to receive details from the package that implements voice search. 314 * <p> 315 * This is based on the value specified by the voice search {@link Activity} in 316 * {@link #DETAILS_META_DATA}, and if this is not specified, will return null. Also if there 317 * is no chosen default to resolve for {@link #ACTION_WEB_SEARCH}, this will return null. 318 * <p> 319 * If an intent is returned and is fired, a {@link Bundle} of extras will be returned to the 320 * provided result receiver, and should ideally contain values for 321 * {@link #EXTRA_LANGUAGE_PREFERENCE} and {@link #EXTRA_SUPPORTED_LANGUAGES}. 322 * <p> 323 * (Whether these are actually provided is up to the particular implementation. It is 324 * recommended that {@link Activity}s implementing {@link #ACTION_WEB_SEARCH} provide this 325 * information, but it is not required.) 326 * 327 * @param context a context object 328 * @return the broadcast intent to fire or null if not available 329 */ getVoiceDetailsIntent(Context context)330 public static final Intent getVoiceDetailsIntent(Context context) { 331 Intent voiceSearchIntent = new Intent(ACTION_WEB_SEARCH); 332 ResolveInfo ri = context.getPackageManager().resolveActivity( 333 voiceSearchIntent, PackageManager.GET_META_DATA); 334 if (ri == null || ri.activityInfo == null || ri.activityInfo.metaData == null) return null; 335 336 String className = ri.activityInfo.metaData.getString(DETAILS_META_DATA); 337 if (className == null) return null; 338 339 Intent detailsIntent = new Intent(ACTION_GET_LANGUAGE_DETAILS); 340 detailsIntent.setComponent(new ComponentName(ri.activityInfo.packageName, className)); 341 return detailsIntent; 342 } 343 344 /** 345 * Meta-data name under which an {@link Activity} implementing {@link #ACTION_WEB_SEARCH} can 346 * use to expose the class name of a {@link BroadcastReceiver} which can respond to request for 347 * more information, from any of the broadcast intents specified in this class. 348 * <p> 349 * Broadcast intents can be directed to the class name specified in the meta-data by creating 350 * an {@link Intent}, setting the component with 351 * {@link Intent#setComponent(android.content.ComponentName)}, and using 352 * {@link Context#sendOrderedBroadcast(Intent, String, BroadcastReceiver, android.os.Handler, int, String, android.os.Bundle)} 353 * with another {@link BroadcastReceiver} which can receive the results. 354 * <p> 355 * The {@link #getVoiceDetailsIntent(Context)} method is provided as a convenience to create 356 * a broadcast intent based on the value of this meta-data, if available. 357 * <p> 358 * This is optional and not all {@link Activity}s which implement {@link #ACTION_WEB_SEARCH} 359 * are required to implement this. Thus retrieving this meta-data may be null. 360 */ 361 public static final String DETAILS_META_DATA = "android.speech.DETAILS"; 362 363 /** 364 * A broadcast intent which can be fired to the {@link BroadcastReceiver} component specified 365 * in the meta-data defined in the {@link #DETAILS_META_DATA} meta-data of an 366 * {@link Activity} satisfying {@link #ACTION_WEB_SEARCH}. 367 * <p> 368 * When fired with 369 * {@link Context#sendOrderedBroadcast(Intent, String, BroadcastReceiver, android.os.Handler, int, String, android.os.Bundle)}, 370 * a {@link Bundle} of extras will be returned to the provided result receiver, and should 371 * ideally contain values for {@link #EXTRA_LANGUAGE_PREFERENCE} and 372 * {@link #EXTRA_SUPPORTED_LANGUAGES}. 373 * <p> 374 * (Whether these are actually provided is up to the particular implementation. It is 375 * recommended that {@link Activity}s implementing {@link #ACTION_WEB_SEARCH} provide this 376 * information, but it is not required.) 377 */ 378 public static final String ACTION_GET_LANGUAGE_DETAILS = 379 "android.speech.action.GET_LANGUAGE_DETAILS"; 380 381 /** 382 * Specify this boolean extra in a broadcast of {@link #ACTION_GET_LANGUAGE_DETAILS} to 383 * indicate that only the current language preference is needed in the response. This 384 * avoids any additional computation if all you need is {@link #EXTRA_LANGUAGE_PREFERENCE} 385 * in the response. 386 */ 387 public static final String EXTRA_ONLY_RETURN_LANGUAGE_PREFERENCE = 388 "android.speech.extra.ONLY_RETURN_LANGUAGE_PREFERENCE"; 389 390 /** 391 * The key to the extra in the {@link Bundle} returned by {@link #ACTION_GET_LANGUAGE_DETAILS} 392 * which is a {@link String} that represents the current language preference this user has 393 * specified - a locale string like "en-US". 394 */ 395 public static final String EXTRA_LANGUAGE_PREFERENCE = 396 "android.speech.extra.LANGUAGE_PREFERENCE"; 397 398 /** 399 * The key to the extra in the {@link Bundle} returned by {@link #ACTION_GET_LANGUAGE_DETAILS} 400 * which is an {@link ArrayList} of {@link String}s that represents the languages supported by 401 * this implementation of voice recognition - a list of strings like "en-US", "cmn-Hans-CN", 402 * etc. 403 */ 404 public static final String EXTRA_SUPPORTED_LANGUAGES = 405 "android.speech.extra.SUPPORTED_LANGUAGES"; 406 407 /** 408 * Optional boolean, to be used with {@link #ACTION_RECOGNIZE_SPEECH}, 409 * {@link #ACTION_VOICE_SEARCH_HANDS_FREE}, {@link #ACTION_WEB_SEARCH} to indicate whether to 410 * only use an offline speech recognition engine. The default is false, meaning that either 411 * network or offline recognition engines may be used. 412 */ 413 public static final String EXTRA_PREFER_OFFLINE = "android.speech.extra.PREFER_OFFLINE"; 414 } 415