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