# Accessibility

The **Accessibility** module implements the accessibility functions, including obtaining the accessibility application list, accessibility application enabled status, and captions configuration.

> **NOTE**
>
> The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.

## Modules to Import

```typescript
import accessibility from '@ohos.accessibility';
```

## AbilityState

Enumerates the states of an accessibility application.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

| Name| Description|
| -------- | -------- |
| enable | The accessibility application is enabled.|
| disable | The accessibility application is disabled.|
| install | The accessibility application has been installed.|

## AbilityType

Enumerates the types of accessibility applications.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

| Name| Description|
| -------- | -------- |
| audible | The accessibility application provides audible feedback.|
| generic | The accessibility application provides generic feedback.|
| haptic | The accessibility application provides haptic feedback.|
| spoken  | The accessibility application provides spoken feedback.|
| visual | The accessibility application provides visual feedback.|
| all<sup>9+</sup> | All the preceding types.|

## AccessibilityAbilityInfo

Provides information about an accessibility application.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

### Attributes

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| id | number | Yes| No| Ability ID.|
| name | string | Yes| No| Ability name.|
| bundleName | string | Yes| No| Bundle name.|
| targetBundleNames<sup>9+</sup> | Array&lt;string&gt; | Yes| No| Name of the target bundle.|
| abilityTypes | Array&lt;[AbilityType](#abilitytype)&gt; | Yes| No| Accessibility application type.|
| capabilities | Array&lt;[Capability](#capability)&gt; | Yes| No| Capabilities list of the accessibility application.|
| description | string | Yes| No| Description of the accessibility application.|
| eventTypes | Array&lt;[EventType](#eventtype)&gt; | Yes| No| List of events that the accessibility application focuses on.|

## Action

Describes the target action supported by an accessibility application.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

| Name| Description|
| -------- | -------- |
| click | Clicking.|
| longClick | Long pressing.|
| scrollForward | Scrolling forward.|
| scrollBackward | Scrolling backward.|
| focus | Obtaining focus.|
| clearFocus | Clearing focus.|
| clearSelection | Clearing selection.|
| accessibilityFocus | Obtaining the accessibility focus.|
| clearAccessibilityFocus | Clearing the accessibility focus.|
| cut | Cut.|
| copy | Copy.|
| paste | Paste.|
| select | Select.|
| setText | Setting the text.|
| delete | Delete.|
| setSelection | Setting the selection.|

## Capability

Enumerates the capabilities of an auxiliary application.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

| Name| Description|
| -------- | -------- |
| retrieve | Capability to retrieve the window content.|
| touchGuide | Capability of touch guide mode.|
| keyEventObserver | Capability to filter key events.|
| zoom | Capability to control the display zoom level.|
| gesture | Capability to perform gesture actions.|

## CaptionsFontEdgeType<sup>8+</sup>

Enumerates the font edge types of captions.

**System capability**: SystemCapability.BarrierFree.Accessibility.Hearing

| Name| Description|
| -------- | -------- |
| none | No effect.|
| raised | Raised effect.|
| depressed | Depressed effect.|
| uniform | Uniform effect.|
| dropShadow | Drop shadow effect.|

## CaptionsFontFamily<sup>8+</sup>

Enumerates the font families of captions.

**System capability**: SystemCapability.BarrierFree.Accessibility.Hearing

| Name| Description|
| -------- | -------- |
| default | Default font family.|
| monospacedSerif | Monospaced Serif fonts, which use the same width for each character.|
| serif | Serif fonts.|
| monospacedSansSerif | Monospaced Sans Serif fonts, which use the same width for each character.|
| sansSerif | Sans Serif fonts.|
| casual | Casual fonts.|
| cursive | Cursive fonts.|
| smallCapitals | Small caps fonts.|

## CaptionsStyle<sup>8+</sup>

Describes the style of captions.

**System capability**: SystemCapability.BarrierFree.Accessibility.Hearing

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| fontFamily | [CaptionsFontFamily](#captionsfontfamily8) | Yes| No| Font family of captions.|
| fontScale | number | Yes| No| Font scale of captions.|
| fontColor | number \| string | Yes| No| Font color of captions.|
| fontEdgeType | [CaptionsFontEdgeType](#captionsfontedgetype8) | Yes| No| Font edge type of captions.|
| backgroundColor | number \| string | Yes| No| Background color of captions.|
| windowColor | number \| string | Yes| No| Window color of captions.|

## CaptionsManager<sup>8+</sup>

Implements configuration management for captions.

**System capability**: SystemCapability.BarrierFree.Accessibility.Hearing

### Attributes

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| enabled | boolean | Yes| No| Whether to enable captions configuration.|
| style | [CaptionsStyle](#captionsstyle8) | Yes| No| Style of captions.|

In the following API examples, you must first use the [accessibility.getCaptionsManager()](#accessibilitygetcaptionsmanager8) API to obtain a **captionsManager** instance, and then call the methods using the obtained instance.

### on('enableChange')

on(type: 'enableChange', callback: Callback&lt;boolean&gt;): void;

Enables listening for the enabled status changes of captions configuration.

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | type | string | Yes| Type of the event to listen for, which is set to **enableChange** in this API.|
  | callback | Callback&lt;boolean&gt; | Yes| Callback invoked when the enabled status of captions configuration changes.|

- **Example**

  ```typescript
  captionsManager.on('enableChange',(data) => {
      console.info('success data:subscribeStateObserver : ' + JSON.stringify(data))
  })
  ```

### on('styleChange')

on(type: 'styleChange', callback: Callback&lt;CaptionsStyle&gt;): void;

Enables listening for captions style changes.

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | type | string | Yes| Type of the event to listen for, which is set to **styleChange** in this API.|
  | callback | Callback&lt;[CaptionsStyle](#captionsstyle8)&gt; | Yes| Callback invoked when the style of captions changes.|

- **Example**

  ```typescript
  captionsManager.on('styleChange',(data) => {
      console.info('success data:subscribeStateObserver : ' + JSON.stringify(data))
  })
  ```
  
### off('enableChange')

off(type: 'enableChange', callback?: Callback&lt;boolean&gt;): void;

Disables listening for the enabled status changes of captions configuration.

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | type | string | Yes| Type of the event to listen for, which is set to **enableChange** in this API.|
  | callback | Callback&lt;boolean&gt; | No| Callback invoked when the enabled status of captions configuration changes.|

- **Example**

  ```typescript
  captionsManager.off('enableChange')
  ```

### off('styleChange')

off(type: 'styleChange', callback?: Callback&lt;CaptionsStyle&gt;): void;

Disables listening for captions style changes.

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | type | string | Yes| Type of the event to listen for, which is set to **styleChange** in this API.|
  | callback | Callback&lt;[CaptionsStyle](#captionsstyle8)&gt; | No| Callback invoked when the style of captions changes.|

- **Example**

  ```typescript
  captionsManager.off('styleChange')
  ```

## EventInfo

Describes a GUI change event.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

### Attributes

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| type | [EventType](#eventtype) | Yes| Yes| Accessibility event type.|
| windowUpdateType | [WindowUpdateType](#windowupdatetype) | Yes| Yes| Window update type.|
| bundleName | string | Yes| Yes| Target application name.|
| componentType | string | Yes| Yes| Type of the event source component, for example, button or chart.|
| pageId | number | Yes| Yes| Page ID of the event source.|
| description | string | Yes| Yes| Event description.|
| triggerAction | [Action](#action) | Yes| Yes| Action that triggers the event.|
| textMoveUnit | [TextMoveUnit](#textmoveunit) | Yes| Yes| Text movement unit.|
| contents | Array&lt;string&gt; | Yes| Yes| Array of contents.|
| lastContent | string | Yes| Yes| Latest content.|
| beginIndex | number | Yes| Yes| Sequence number of the first item displayed on the page.|
| currentIndex | number | Yes| Yes| Sequence number of the current item.|
| endIndex | number | Yes| Yes| Sequence number of the last item displayed on the page.|
| itemCount | number | Yes| Yes| Total number of items.|

### constructor

constructor(jsonObject)

Implements a constructor.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | jsonObject | string | Yes| JSON string required for creating an object.|

- **Example**

  ```typescript
  let eventInfo = new accessibility.EventInfo({"type":"click","bundleName":"com.example.MyApplication","triggerAction":"click"})
  ```

## EventType

Enumerates accessibility event types.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

| Name| Description|
| -------- | -------- |
| click | Event of clicking a component.|
| longClick | Event of long-pressing a component.|
| select | Event of selecting a component.|
| focus | Event indicating that the component obtains the focus.|
| textUpdate | Event indicating that the component text has been updated.|
| hoverEnter | Event indicating that the hover enters a component.|
| hoverExit | Event indicating that the hover exits a component.|
| scroll | Event of the scroll view.|
| textSelectionUpdate | Event indicating that the selected text has been updated.|
| accessibilityFocus | Event indicating that the accessibility focus has been obtained.|
| accessibilityFocusClear | Event indicating that the accessibility focus has been cleared.|

## TextMoveUnit

Enumerates the movement units for traversing the node text.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

| Name| Description|
| -------- | -------- |
| char | The movement unit for traversing the node text is by character.|
| word | The movement unit for traversing the node text is by word.|
| line | The movement unit for traversing the node text is by line.|
| page | The movement unit for traversing the node text is by page.|
| paragraph | The movement unit for traversing the node text is by paragraph.|

## WindowUpdateType

Enumerates window update types.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

| Name| Description|
| -------- | -------- |
| add | Window adding.|
| remove | Window deletion.|
| bounds | Window boundary change.|
| active | Window activity change.|
| focus | Window focus change.|

## accessibility.getAbilityLists

getAbilityLists(abilityType: AbilityType, stateType: AbilityState): Promise&lt;Array&lt;AccessibilityAbilityInfo&gt;&gt;

Obtains the accessibility application list. This API uses a promise to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | abilityType | [AbilityType](#abilitytype) | Yes| Accessibility application type.|
  | stateType | [AbilityState](#abilitystate) | Yes| Accessibility application status.|

- **Return value**

  | Type| Description|
  | -------- | -------- |
  | Promise&lt;Array&lt;[AccessibilityAbilityInfo](#accessibilityabilityinfo)&gt;&gt; | Promise used to return the accessibility application list.|

- **Example**

  ```typescript
  accessibility.getAbilityLists("spoken", "enable")
      .then((data) => {
          console.info('success data:getAbilityList1 : ' + JSON.stringify(data));
          for (let item of data) {
              console.info(item.id);
              console.info(item.name);
              console.info(item.description);
              console.info(item.abilityTypes);
              console.info(item.eventTypes);
              console.info(item.capabilities);
              console.info(item.packageName);
              console.info(item.filterBundleNames);
              console.info(item.bundleName);
          }
      }).catch((error) => {
          console.error('failed to  getAbilityList1 because ' + JSON.stringify(error));
      })
  ```

## accessibility.getAbilityLists

getAbilityLists(abilityType: AbilityType, stateType: AbilityState,callback: AsyncCallback&lt;Array&lt;AccessibilityAbilityInfo&gt;&gt;): void

Obtains the accessibility application list. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | abilityType | [AbilityType](#abilitytype) | Yes| Accessibility application type.|
  | stateType | [AbilityState](#abilitystate) | Yes| Accessibility application status.|
  | callback | AsyncCallback&lt;Array&lt;[AccessibilityAbilityInfo](#accessibilityabilityinfo)&gt;&gt; | Yes| Callback used to return the accessibility application list.|

- **Example**

  ```typescript
  accessibility.getAbilityLists("visual", "enable", (err, data) => {
      if (err) {
          console.error('failed to getAbilityList2 because ' + JSON.stringify(err));
          return;
      }
      console.info('success data:getAbilityList2 : ' + JSON.stringify(data));
      for (let item of data) {
          console.info(item.id);
          console.info(item.name);
          console.info(item.description);
          console.info(item.abilityTypes);
          console.info(item.eventTypes);
          console.info(item.capabilities);
          console.info(item.packageName);
          console.info(item.filterBundleNames);
          console.info(item.bundleName);
      }
  })
  ```

## accessibility.getCaptionsManager<sup>8+</sup>

getCaptionsManager(): CaptionsManager

Obtains the captions configuration.

**System capability**: SystemCapability.BarrierFree.Accessibility.Hearing

- **Return value**

  | Type| Description|
  | -------- | -------- |
  | [CaptionsManager](#captionsmanager8) | Captions configuration.|

- **Example**

  ```typescript
  captionsManager = accessibility.getCaptionsManager()
  ```

## accessibility.on('accessibilityStateChange' | 'touchGuideStateChange')

on(type: 'accessibilityStateChange' | 'touchGuideStateChange', callback: Callback&lt;boolean&gt;): void

Enables listening for the enabled status changes of the accessibility application or touch guide mode.

 

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | type | string | Yes| Type of the event to listen for.<br>- **'accessibilityStateChange'** means to listen for the enabled status changes of the accessibility application.<br>**System capability**: SystemCapability.BarrierFree.Accessibility.Core<br>- **'touchGuideStateChange'** means to listen for the enabled status changes of the touch guide mode.<br>**System capability**: SystemCapability.BarrierFree.Accessibility.Vision|
  | callback | Callback\<boolean> | Yes| Callback invoked when the enabled status of captions configuration changes.|

- **Example**

  ```typescript
  accessibility.on('accessibilityStateChange',(data) => { 
      console.info('success data:subscribeStateObserver : ' + JSON.stringify(data))
  })
  ```

## accessibility.off('accessibilityStateChange' | 'touchGuideStateChange')

off(type: 'accessibilityStateChange ' | 'touchGuideStateChange', callback?: Callback&lt;boolean&gt;): void

Disables listening for the enabled status changes of the accessibility application or touch guide mode.

 

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | type |  string | No| Type of the event to listen for.<br>- **'accessibilityStateChange'** means to listen for the enabled status changes of the accessibility application.<br>**System capability**: SystemCapability.BarrierFree.Accessibility.Core<br>- **'touchGuideStateChange'** means to listen for the enabled status changes of the touch guide mode.<br>**System capability**: SystemCapability.BarrierFree.Accessibility.Vision|
  | callback | Callback&lt;boolean&gt; | No| Callback invoked when the enabled status changes.|

- **Example**

  ```typescript
  accessibility.off('accessibilityStateChange',(data) => {
      console.info('success data:unSubscribeStateObserver : ' + JSON.stringify(data))
  })
  ```

## accessibility.isOpenAccessibility

isOpenAccessibility(): Promise&lt;boolean&gt;

Checks whether accessibility is enabled. This API uses a promise to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

- **Return value**

  | Type| Description|
  | -------- | -------- |
  | Promise&lt;boolean&gt; | Returns **true** if accessibility is enabled; returns **false** otherwise.|

- **Example**

  ```typescript
  accessibility.isOpenAccessibility()
      .then((data) => {
          console.info('success data:isOpenAccessibility : ' + JSON.stringify(data))
      }).catch((error) => {
          console.error('failed to  isOpenAccessibility because ' + JSON.stringify(error));
      })
  ```

## accessibility.isOpenAccessibility

isOpenAccessibility(callback: AsyncCallback&lt;boolean&gt;): void

Checks whether accessibility is enabled. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | callback | AsyncCallback&lt;boolean&gt; | Yes| Callback used to return the result. Returns **true** if accessibility is enabled; returns **false** otherwise.|

- **Example**

  ```typescript
  accessibility.isOpenAccessibility((err, data) => {
      if (err) {
          console.error('failed to isOpenAccessibility because ' + JSON.stringify(err));
          return;
      }
      console.info('success data:isOpenAccessibility : ' + JSON.stringify(data))
  })
  ```

## accessibility.isOpenTouchGuide

isOpenTouchGuide(): Promise&lt;boolean&gt;

Checks whether touch guide mode is enabled. This API uses a promise to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Vision

- **Return value**

  | Type| Description|
  | -------- | -------- |
  | Promise&lt;boolean&gt; | Returns **true** if touch guide mode is enabled; returns **false** otherwise.|

- **Example**

  ```typescript
  accessibility.isOpenTouchGuide()
      .then((data) => {
          console.info('success data:isOpenTouchGuide : ' + JSON.stringify(data))
      }).catch((error) => {
          console.error('failed to  isOpenTouchGuide because ' + JSON.stringify(error));
      })
  ```

## accessibility.isOpenTouchGuide

isOpenTouchGuide(callback: AsyncCallback&lt;boolean&gt;): void

Checks whether touch guide mode is enabled. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Vision

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | callback | AsyncCallback&lt;boolean&gt; | Yes| Callback used to return the result. Returns **true** if touch guide mode is enabled; returns **false** otherwise.|

- **Example**

  ```typescript
  accessibility.isOpenTouchGuide((err, data) => {
      if (err) {
          console.error('failed to isOpenTouchGuide because ' + JSON.stringify(err));
          return;
      }
      console.info('success data:isOpenTouchGuide : ' + JSON.stringify(data))
  })
  ```

## accessibility.sendEvent

sendEvent(event: EventInfo): Promise&lt;void&gt;

Sends an accessibility event. This API uses a promise to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | event | [EventInfo](#eventinfo) | Yes| Accessibility event.|

- **Return value**

  | Type| Description|
  | -------- | -------- |
  | Promise&lt;void&gt; | Promise used to return the result. Returns data if the accessibility event is sent successfully; returns an error otherwise.|

- **Example**

  ```typescript
  accessibility.sendEvent(this.eventInfo)
      .then((data) => {
          console.info('success data:sendEvent : ' + JSON.stringify(data))
      }).catch((error) => {
          console.error('failed to  sendEvent because ' + JSON.stringify(error));
      })
  ```

## accessibility.sendEvent

sendEvent(event: EventInfo, callback: AsyncCallback&lt;void&gt;): void

Sends an accessibility event. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.BarrierFree.Accessibility.Core

- **Parameters**

  | Name| Type| Mandatory| Description|
  | -------- | -------- | -------- | -------- |
  | event | [EventInfo](#eventinfo) | Yes| Accessibility event.|
  | callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result. Returns data if the accessibility event is sent successfully; returns an error otherwise.|

- **Example**

  ```typescript
  accessibility.sendEvent(this.eventInfo,(err, data) => {
      if (err) {
          console.error('failed to sendEvent because ' + JSON.stringify(err));
          return;
      }   
      console.info('success data:sendEvent : ' + JSON.stringify(data))
  })
  ```