1# @ohos.accessibility.config (SystemAPI) 2 3The **accessibility.config** module provides APIs for configuring system accessibility features, including accessibility extension, high-contrast text, mouse buttons, and captions. 4 5> **NOTE** 6> 7> - The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version. 8> - The APIs provided by this module are system APIs. 9 10## Modules to Import 11 12```ts 13import { config } from '@kit.AccessibilityKit'; 14``` 15 16## Attributes 17 18**System capability**: SystemCapability.BarrierFree.Accessibility.Core 19 20| Name | Type | Readable| Writable| Description | 21|------------------------------------|--------------------------------------------------------------------------------------------| -------- | -------- |-----------------------------------------------------------| 22| highContrastText | [Config](#config)\<boolean> | Yes| Yes| Whether to enable high-contrast text. The value **true** indicates that high-contrast text is enabled, and **false** indicates the opposite.<br>Default value: **false**. | 23| invertColor | [Config](#config)\<boolean> | Yes| Yes| Whether to enable color inversion. The value **true** indicates that color inversion is enabled, and **false** indicates the opposite.<br>Default value: **false**. | 24| daltonizationState<sup>11+</sup> | [Config](#config)\<boolean> | Yes| Yes| Whether to enable daltonization. It must be used with **daltonizationColorFilter**. The value **true** indicates that daltonization is enabled, and **false** indicates the opposite.<br>Default value: **false**. | 25| daltonizationColorFilter | [Config](#config)<[DaltonizationColorFilter](#daltonizationcolorfilter)> | Yes| Yes| Configuration of the daltonization filter. | 26| contentTimeout | [Config](#config)\<number> | Yes| Yes| Recommended duration for content display. The value ranges from 0 to 5000, in milliseconds. Default value: **0**. | 27| animationOff | [Config](#config)\<boolean> | Yes| Yes| Whether to disable animation. The value **true** indicates that animation is disabled, and **false** indicates the opposite.<br>Default value: **0**. | 28| brightnessDiscount | [Config](#config)\<number> | Yes| Yes| Brightness discount. The value ranges from 0 to 1.0. Default value: **0.0**. | 29| mouseKey | [Config](#config)\<boolean> | Yes| Yes| Whether to enable the mouse button. The value **true** indicates that the mouse button is enabled, and **false** indicates the opposite. <br>Default value: **0**. | 30| mouseAutoClick | [Config](#config)\<number> | Yes| Yes| Configuration of the automatic mouse click operation. The value ranges from 0 to 5000, in milliseconds. The value **0** indicates that the automatic mouse click is not triggered; other values indicate that the operation is triggered when the mouse pointer is hovered for a specified period of time.<br>Default value: **0**. | 31| shortkey | [Config](#config)\<boolean> | Yes| Yes| Whether to enable the accessibility extension shortcut key. The value **true** indicates that the auxiliary extension shortcut key is enabled, and **false** indicates the opposite.<br>Default value: **false**. | 32| shortkeyTarget | [Config](#config)\<string> | Yes| Yes| Target application for the accessibility extension shortcut key. The value format is 'bundleName/abilityName'. | 33| captions | [Config](#config)\<boolean> | Yes| Yes| Whether to enable captions. The value **true** indicates that caption is enabled, and **false** indicates the opposite.<br>Default value: **false**. | 34| captionsStyle | [Config](#config)\<[accessibility.CaptionsStyle](js-apis-accessibility.md#captionsstyle8)> | Yes| Yes| Captions style. | 35| audioMono<sup>10+</sup> | [Config](#config)\<boolean> | Yes| Yes| Whether to enable mono audio. The value **true** indicates that mono audio is enabled, and **false** indicates the opposite.<br>Default value: **false**. | 36| audioBalance<sup>10+</sup> | [Config](#config)\<number> | Yes| Yes| Audio balance for the left and right audio channels. The value ranges from -1.0 to 1.0. Default value: **0.0**. | 37| shortkeyMultiTargets<sup>11+</sup> | [Config](#config)<Array\<string>> | Yes| Yes| List of target applications for the accessibility shortcut keys. The value format is ['bundleName/abilityName'].| 38| clickResponseTime<sup>11+</sup> | [Config](#config)<[ClickResponseTime](#clickresponsetime11)> | Yes| Yes| Length of time required for a click. | 39| ignoreRepeatClick<sup>11+</sup> | [Config](#config)\<boolean> | Yes| Yes| Whether to ignore repeated clicks. This parameter must be used together with **repeatClickInterval**. The value **true** indicates that the feature of ignoring repeated clicks is enabled, and **false** indicates the opposite.<br>Default value: **false**. | 40| repeatClickInterval<sup>11+</sup> | [Config](#config)<[RepeatClickInterval](#repeatclickinterval11)> | Yes| Yes| Interval between repeated clicks. | 41 42For a boolean return value, **True** means that the feature is enabled, and **False** means the opposite. 43[]() 44## enableAbility 45 46enableAbility(name: string, capability: Array<accessibility.Capability>): Promise<void>; 47 48**Required permissions**: ohos.permission.WRITE_ACCESSIBILITY_CONFIG 49 50Enables an accessibility extension ability. This API uses a promise to return the result. 51 52**System capability**: SystemCapability.BarrierFree.Accessibility.Core 53 54**Parameters** 55 56| Name| Type | Mandatory| Description| 57| -------- |------------------------------------------------------------------------------| -------- | -------- | 58| name | string | Yes| Name of the accessibility extension ability. The format is 'bundleName/abilityName'.| 59| capability | Array<[accessibility.Capability](js-apis-accessibility.md#capability)> | Yes| Capability of the accessibility extension ability.| 60 61**Return value** 62 63| Type| Description| 64| -------- | -------- | 65| Promise\<void>| Promise that returns no value.| 66 67**Error codes** 68 69For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 70 71| Error Code| Error Message| 72| ------- | -------------------------------- | 73| 201 | Permission verification failed. The application does not have the permission required to call the API. | 74| 202 | Permission verification failed. A non-system application calls a system API. | 75| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 76| 9300001 | Invalid bundle name or ability name. | 77| 9300002 | Target ability already enabled. | 78 79**Example** 80 81```ts 82import { accessibility, config } from '@kit.AccessibilityKit'; 83import { BusinessError } from '@kit.BasicServicesKit'; 84 85let name: string = 'com.ohos.example/axExtension'; 86let capability: accessibility.Capability[] = ['retrieve']; 87 88config.enableAbility(name, capability).then(() => { 89 console.info(`Succeeded in enable ability, name is ${name}, capability is ${capability}`); 90}).catch((err: BusinessError) => { 91 console.error(`failed to enable ability, Code is ${err.code}, message is ${err.message}`); 92}); 93``` 94 95## enableAbility 96 97enableAbility(name: string, capability: Array<[accessibility.Capability](js-apis-accessibility.md#capability)>, callback: AsyncCallback<void>): void; 98 99**Required permissions**: ohos.permission.WRITE_ACCESSIBILITY_CONFIG 100 101Enables an accessibility extension ability. This API uses an asynchronous callback to return the result. 102 103**System capability**: SystemCapability.BarrierFree.Accessibility.Core 104 105**Parameters** 106 107| Name| Type | Mandatory| Description| 108| -------- |---------------------------------------------------------------------------------| -------- | -------- | 109| name | string | Yes| Name of the accessibility extension ability. The format is 'bundleName/abilityName'.| 110| capability | Array<[accessibility.Capability](js-apis-accessibility.md#capability)> | Yes| Capability of the accessibility extension ability.| 111| callback | AsyncCallback<void> | Yes| Callback used to return the result.| 112 113**Error codes** 114 115For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 116 117| Error Code| Error Message| 118| ------- | -------------------------------- | 119| 201 | Permission verification failed. The application does not have the permission required to call the API. | 120| 202 | Permission verification failed. A non-system application calls a system API. | 121| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 122| 9300001 | Invalid bundle name or ability name. | 123| 9300002 | Target ability already enabled. | 124 125**Example** 126 127```ts 128import { accessibility, config } from '@kit.AccessibilityKit'; 129import { BusinessError } from '@kit.BasicServicesKit'; 130 131let name: string = 'com.ohos.example/axExtension'; 132let capability: accessibility.Capability[] = ['retrieve']; 133 134config.enableAbility(name, capability, (err: BusinessError) => { 135 if (err) { 136 console.error(`failed to enable ability, Code is ${err.code}, message is ${err.message}`); 137 return; 138 } 139 console.info(`Succeeded in enable ability, name is ${name}, capability is ${capability}`); 140}); 141``` 142 143## disableAbility 144 145disableAbility(name: string): Promise<void>; 146 147**Required permissions**: ohos.permission.WRITE_ACCESSIBILITY_CONFIG 148 149Disables an accessibility extension ability. This API uses a promise to return the result. 150 151**System capability**: SystemCapability.BarrierFree.Accessibility.Core 152 153**Parameters** 154 155| Name| Type| Mandatory| Description| 156| -------- | -------- | -------- | -------- | 157| name | string | Yes| Name of the accessibility extension ability. The format is 'bundleName/abilityName'.| 158 159**Return value** 160 161| Type| Description| 162| -------- | -------- | 163| Promise\<void>| Promise that returns no value.| 164 165**Error codes** 166 167For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 168 169| Error Code| Error Message| 170| ------- | -------------------------------- | 171| 201 | Permission verification failed. The application does not have the permission required to call the API. | 172| 202 | Permission verification failed. A non-system application calls a system API. | 173| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 174| 9300001 | Invalid bundle name or ability name. | 175 176**Example** 177 178```ts 179import { accessibility, config } from '@kit.AccessibilityKit'; 180import { BusinessError } from '@kit.BasicServicesKit'; 181 182let name: string = 'com.ohos.example/axExtension'; 183 184config.disableAbility(name).then(() => { 185 console.info(`Succeeded in disable ability, name is ${name}`); 186}).catch((err: BusinessError) => { 187 console.error(`failed to disable ability, Code is ${err.code}, message is ${err.message}`); 188}) 189``` 190 191## disableAbility 192 193disableAbility(name: string, callback: AsyncCallback<void>): void; 194 195**Required permissions**: ohos.permission.WRITE_ACCESSIBILITY_CONFIG 196 197Disables an accessibility extension ability. This API uses an asynchronous callback to return the result. 198 199**System capability**: SystemCapability.BarrierFree.Accessibility.Core 200 201**Parameters** 202 203| Name| Type| Mandatory| Description| 204| -------- | -------- | -------- | -------- | 205| name | string | Yes| Name of the accessibility extension ability. The format is 'bundleName/abilityName'.| 206| callback | AsyncCallback<void> | Yes| Callback used to return the result.| 207 208**Error codes** 209 210For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 211 212| Error Code| Error Message| 213| ------- | -------------------------------- | 214| 201 | Permission verification failed. The application does not have the permission required to call the API. | 215| 202 | Permission verification failed. A non-system application calls a system API. | 216| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 217| 9300001 | Invalid bundle name or ability name. | 218 219**Example** 220 221```ts 222import { accessibility, config } from '@kit.AccessibilityKit'; 223import { BusinessError } from '@kit.BasicServicesKit'; 224 225let name: string = 'com.ohos.example/axExtension'; 226 227config.disableAbility(name, (err: BusinessError) => { 228 if (err) { 229 console.error(`failed to enable ability, Code is ${err.code}, message is ${err.message}`); 230 return; 231 } 232 console.info(`Succeeded in disable, name is ${name}`); 233}); 234``` 235 236## on('enabledAccessibilityExtensionListChange') 237 238on(type: 'enabledAccessibilityExtensionListChange', callback: Callback<void>): void; 239 240**Required permissions**: ohos.permission.READ_ACCESSIBILITY_CONFIG 241 242Adds a listener for changes in the list of enabled accessibility extension abilities. This API uses an asynchronous callback to return the result. 243 244**System capability**: SystemCapability.BarrierFree.Accessibility.Core 245 246**Parameters** 247 248| Name| Type| Mandatory| Description| 249| -------- | -------- | -------- | -------- | 250| type | string | Yes| Listening type. The value is fixed at **'enabledAccessibilityExtensionListChange'**, indicating listening for changes in the list of enabled accessibility extension abilities.| 251| callback | Callback<void> | Yes| Callback invoked when the list of enabled accessibility extension abilities changes.| 252 253**Error codes** 254 255For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 256 257| Error Code| Error Message| 258| ------- | -------------------------------- | 259| 201 | Permission verification failed. The application does not have the permission required to call the API. | 260| 202 | Permission verification failed. A non-system application calls a system API. | 261| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 262 263**Example** 264 265```ts 266import { config } from '@kit.AccessibilityKit'; 267 268config.on('enabledAccessibilityExtensionListChange', () => { 269 console.info('subscribe enabled accessibility extension list change state success'); 270}); 271``` 272 273## off('enabledAccessibilityExtensionListChange') 274 275off(type: 'enabledAccessibilityExtensionListChange', callback?: Callback<void>): void; 276 277**Required permissions**: ohos.permission.READ_ACCESSIBILITY_CONFIG 278 279Cancels a listener for changes in the list of enabled accessibility extension abilities. This API uses an asynchronous callback to return the result. 280 281**System capability**: SystemCapability.BarrierFree.Accessibility.Core 282 283**Parameters** 284 285| Name| Type| Mandatory| Description| 286| -------- | -------- | -------- | -------- | 287| type | string | Yes| Listening type. The value is fixed at **'enabledAccessibilityExtensionListChange'**, indicating listening for changes in the list of enabled accessibility extension abilities.| 288| callback | Callback<void> | No| Callback for the event. The value must be the same as the value of **callback** in **on('enabledAccessibilityExtensionListChange')**. If this parameter is not specified, listening will be disabled for all callbacks corresponding to the specified type.| 289 290**Error codes** 291 292For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 293 294| Error Code| Error Message| 295| ------- | -------------------------------- | 296| 201 | Permission verification failed. The application does not have the permission required to call the API. | 297| 202 | Permission verification failed. A non-system application calls a system API. | 298| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 299 300**Example** 301 302```ts 303import { config } from '@kit.AccessibilityKit'; 304 305config.off('enabledAccessibilityExtensionListChange', () => { 306 console.info('Unsubscribe enabled accessibility extension list change state success'); 307}); 308``` 309 310## on('installedAccessibilityListChange')<sup>12+</sup> 311 312on(type: 'installedAccessibilityListChange', callback: Callback<void>): void; 313 314**Required permissions**: ohos.permission.READ_ACCESSIBILITY_CONFIG 315 316Adds a listener for changes in the list of installed accessibility extension abilities. This API uses an asynchronous callback to return the result. 317 318**System capability**: SystemCapability.BarrierFree.Accessibility.Core 319 320**Parameters** 321 322| Name| Type| Mandatory| Description| 323| -------- | -------- | -------- | -------- | 324| type | string | Yes| Listening type. The value is fixed at 'installedAccessibilityListChange', indicating listening for changes in the list of enabled accessibility extension abilities.| 325| callback | Callback<void> | Yes| Callback invoked when the list of installed accessibility extension abilities changes.| 326 327**Error codes** 328 329For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 330 331| Error Code| Error Message| 332| ------- | -------------------------------- | 333| 201 | Permission verification failed. The application does not have the permission required to call the API. | 334| 202 | Permission verification failed. A non-system application calls a system API. | 335| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 336 337**Example** 338 339```ts 340import { config } from '@kit.AccessibilityKit'; 341 342config.on('installedAccessibilityListChange', () => { 343 console.info('subscribe installed accessibility extension list change state success'); 344}); 345``` 346 347## off('installedAccessibilityListChange')<sup>12+</sup> 348 349off(type: 'installedAccessibilityListChange', callback?: Callback<void>): void; 350 351**Required permissions**: ohos.permission.READ_ACCESSIBILITY_CONFIG 352 353Cancels a listener for changes in the list of installed accessibility extension abilities. This API uses an asynchronous callback to return the result. 354 355**System capability**: SystemCapability.BarrierFree.Accessibility.Core 356 357**Parameters** 358 359| Name| Type| Mandatory| Description| 360| -------- | -------- | -------- | -------- | 361| type | string | Yes| Listening type. The value is fixed at 'installedAccessibilityListChange', indicating listening for changes in the list of enabled accessibility extension abilities.| 362| callback | Callback<void> | No| Callback for the event. The value must be the same as the value of **callback** in **on('installedAccessibilityListChange')**. If this parameter is not specified, listening will be disabled for all callbacks corresponding to the specified type.| 363 364**Error codes** 365 366For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 367 368| Error Code| Error Message| 369| ------- | -------------------------------- | 370| 201 | Permission verification failed. The application does not have the permission required to call the API. | 371| 202 | Permission verification failed. A non-system application calls a system API. | 372| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 373 374**Example** 375 376```ts 377import { config } from '@kit.AccessibilityKit'; 378 379config.off('installedAccessibilityListChange', () => { 380 console.info('Unsubscribe installed accessibility extension list change state success'); 381}); 382``` 383 384## Config 385 386Implements configuration, acquisition, and listening for attributes. 387 388### set 389 390set(value: T): Promise<void>; 391 392**Required permissions**: ohos.permission.WRITE_ACCESSIBILITY_CONFIG 393 394Sets the attribute value. This API uses a promise to return the result. 395 396**System capability**: SystemCapability.BarrierFree.Accessibility.Core 397 398**Parameters** 399 400| Name| Type| Mandatory| Description| 401| -------- | -------- | -------- | -------- | 402| value | T | Yes| Attribute value to set.| 403 404**Return value** 405 406| Type| Description| 407| -------- | -------- | 408| Promise\<void>| Promise that returns no value.| 409 410**Error codes** 411 412For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 413 414| Error Code| Error Message| 415| ------- | -------------------------------- | 416| 201 | Permission verification failed. The application does not have the permission required to call the API. | 417| 202 | Permission verification failed. A non-system application calls a system API. | 418| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 419 420**Example** 421 422```ts 423import { config } from '@kit.AccessibilityKit'; 424import { BusinessError } from '@kit.BasicServicesKit'; 425 426let value: boolean = true; 427 428config.highContrastText.set(value).then(() => { 429 console.info(`Succeeded in set highContrastText value is ${value}`); 430}).catch((err: BusinessError) => { 431 console.error(`failed to set highContrastText, Code is ${err.code}, message is ${err.message}`); 432}); 433``` 434 435### set 436 437set(value: T, callback: AsyncCallback<void>): void; 438 439**Required permissions**: ohos.permission.WRITE_ACCESSIBILITY_CONFIG 440 441Sets the attribute value. This API uses an asynchronous callback to return the result. 442 443**System capability**: SystemCapability.BarrierFree.Accessibility.Core 444 445**Parameters** 446 447| Name| Type| Mandatory| Description| 448| -------- | -------- | -------- | -------- | 449| value | T | Yes| Attribute value to set.| 450| callback | AsyncCallback<void> | Yes| Callback used to return the result.| 451 452**Error codes** 453 454For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 455 456| Error Code| Error Message| 457| ------- | -------------------------------- | 458| 201 | Permission verification failed. The application does not have the permission required to call the API. | 459| 202 | Permission verification failed. A non-system application calls a system API. | 460| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 461 462**Example** 463 464```ts 465import { config } from '@kit.AccessibilityKit'; 466import { BusinessError } from '@kit.BasicServicesKit'; 467 468let value: boolean = true; 469 470config.highContrastText.set(value, (err: BusinessError) => { 471 if (err) { 472 console.error(`failed to set highContrastText, Code is ${err.code}, message is ${err.message}`); 473 return; 474 } 475 console.info(`Succeeded in set highContrastText, value is ${value}`); 476}); 477``` 478 479### get 480 481get(): Promise<T>; 482 483Obtains the attribute value. This API uses a promise to return the result. 484 485**System capability**: SystemCapability.BarrierFree.Accessibility.Core 486 487**Return value** 488 489| Type| Description| 490| -------- | -------- | 491| Promise<T> | Promise used to return the value obtained.| 492 493**Error codes** 494 495For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 496 497| Error Code| Error Message| 498| ------- | -------------------------------- | 499| 201 | Permission verification failed. The application does not have the permission required to call the API. | 500| 202 | Permission verification failed. A non-system application calls a system API. | 501 502**Example** 503 504```ts 505import { config } from '@kit.AccessibilityKit'; 506import { BusinessError } from '@kit.BasicServicesKit'; 507 508config.highContrastText.get().then((data: boolean) => { 509 console.info(`Succeeded in get highContrastText, data is ${data}`); 510}).catch((err: BusinessError) => { 511 console.error(`failed to get highContrastText, Code is ${err.code}, message is ${err.message}`); 512}); 513``` 514 515### get 516 517get(callback: AsyncCallback<T>): void; 518 519Obtains the attribute value. This API uses an asynchronous callback to return the result. 520 521**System capability**: SystemCapability.BarrierFree.Accessibility.Core 522 523**Parameters** 524 525| Name| Type| Mandatory| Description| 526| -------- | -------- | -------- | -------- | 527| callback | AsyncCallback<T> | Yes| Callback used to return the attribute value.| 528 529**Error codes** 530 531For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 532 533| Error Code| Error Message| 534| ------- | -------------------------------- | 535| 202 | Permission verification failed. A non-system application calls a system API. | 536 537**Example** 538 539```ts 540import { config } from '@kit.AccessibilityKit'; 541import { BusinessError } from '@kit.BasicServicesKit'; 542 543config.highContrastText.get((err: BusinessError, data: boolean) => { 544 if (err) { 545 console.error(`failed to get highContrastText, Code is ${err.code}, message is ${err.message}`); 546 return; 547 } 548 console.info(`Succeeded in get highContrastText, data is ${data}`); 549}); 550``` 551 552### on 553 554on(callback: Callback<T>): void; 555 556**Required permissions**: ohos.permission.READ_ACCESSIBILITY_CONFIG 557 558Adds a listener for attribute changes. This API uses an asynchronous callback to return the result. 559 560**System capability**: SystemCapability.BarrierFree.Accessibility.Core 561 562**Parameters** 563 564| Name| Type| Mandatory| Description| 565| -------- | -------- | -------- | -------- | 566| callback | Callback<T> | Yes| Callback invoked when the attribute changes.| 567 568**Error codes** 569 570For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 571 572| Error Code| Error Message| 573| ------- | -------------------------------- | 574| 201 | Permission verification failed. The application does not have the permission required to call the API. | 575| 202 | Permission verification failed. A non-system application calls a system API. | 576| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. | 577 578**Example** 579 580```ts 581import { config } from '@kit.AccessibilityKit'; 582 583config.highContrastText.on((data: boolean) => { 584 console.info(`subscribe highContrastText success, result: ${JSON.stringify(data)}`); 585}); 586``` 587 588### off 589 590off(callback?: Callback<T>): void; 591 592**Required permissions**: ohos.permission.READ_ACCESSIBILITY_CONFIG 593 594Cancels the listener for attribute changes. This API uses an asynchronous callback to return the result. 595 596**System capability**: SystemCapability.BarrierFree.Accessibility.Core 597 598**Parameters** 599 600| Name| Type| Mandatory| Description| 601| -------- | -------- | -------- | -------- | 602| callback | Callback<T> | No| Callback for the event. The value must be the same as the value of **callback** in **on()**. If this parameter is not specified, listening will be disabled for all callbacks corresponding to the specified type.| 603 604**Error codes** 605 606For details about the error codes, see [Accessibility Error Codes](errorcode-accessibility.md). 607 608| Error Code| Error Message| 609| ------- | -------------------------------- | 610| 201 | Permission verification failed. The application does not have the permission required to call the API. | 611| 202 | Permission verification failed. A non-system application calls a system API. | 612 613**Example** 614 615```ts 616import { config } from '@kit.AccessibilityKit'; 617 618config.highContrastText.off((data: boolean) => { 619 console.info(`Unsubscribe highContrastText success, result: ${JSON.stringify(data)}`); 620}); 621``` 622 623## DaltonizationColorFilter 624 625Enumerates the daltonization filters. 626**DaltonizationColorFilter** takes effect only when the daltonization filter is enabled ([daltonizationState](#attributes) set to **true**). 627 628**System capability**: SystemCapability.BarrierFree.Accessibility.Core 629 630| Name| Description| 631| -------- | -------- | 632| Normal | Filter for normal users.| 633| Protanomaly | Filter for protanomaly.| 634| Deuteranomaly | Filter for deuteranomaly.| 635| Tritanomaly | Filter for tritanomaly.| 636 637## ClickResponseTime<sup>11+</sup> 638 639Defines the length of time for a click. 640 641**System capability**: SystemCapability.BarrierFree.Accessibility.Core 642 643| Name | Description | 644|-------------|------------| 645| Short | Short (default). | 646| Medium | Medium. | 647| Long | Long. | 648 649## RepeatClickInterval<sup>11+</sup> 650 651Defines the interval between repeated clicks. 652**RepeatClickInterval** takes effect only when repeated clicks are ignored ([ignoreRepeatClick](#attributes) set to **true**). 653 654**System capability**: SystemCapability.BarrierFree.Accessibility.Core 655 656| Name | Description | 657|----------|-------| 658| Shortest | Shortest.| 659| Short | Short. | 660| Medium | Medium. | 661| Long | Long. | 662| Longest | Longest.| 663