# AccessibilityExtensionContext

The **AccessibilityExtensionContext** module, inherited from **ExtensionContext**, provides context for **Accessibility Extension** abilities.

You can use the APIs of this module to configure the concerned information, obtain root information, and inject gestures.

> **NOTE**
>
> 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.
> The APIs of this module can be used only in the stage model.

## Usage

Before using the **AccessibilityExtensionContext** module, you must define a child class that inherits from **AccessibilityExtensionAbility**.

```js
import AccessibilityExtensionAbility from '@ohos.application.AccessibilityExtensionAbility'
class MainAbility extends AccessibilityExtensionAbility {
    onConnect(): void {
        console.log("AxExtensionAbility onConnect");
        let axContext = this.context;
    }
}
```

## FocusDirection

Enumerates the focus directions.

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

| Name      | Description     |
| -------- | ------- |
| up       | Search for the next focusable item above the current item in focus.|
| down     | Search for the next focusable item below the current item in focus.|
| left     | Search for the next focusable item on the left of the current item in focus.|
| right    | Search for the next focusable item on the right of the current item in focus.|
| forward  | Search for the next focusable item before the current item in focus.|
| backward | Search for the next focusable item after the current item in focus.|

## FocusType

Enumerates the focus types.

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

| Name           | Description         |
| ------------- | ----------- |
| accessibility | Accessibility focus.|
| normal        | Normal focus. |

## Rect

Defines a rectangle.

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

| Name    | Type  | Readable  | Writable  | Description       |
| ------ | ------ | ---- | ---- | --------- |
| left   | number | Yes   | No   | Left boundary of the rectangle.|
| top    | number | Yes   | No   | Top boundary of the rectangle.|
| width  | number | Yes   | No   | Width of the rectangle. |
| height | number | Yes   | No   | Height of the rectangle. |

## WindowType

Enumerates the window types.

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

| Name         | Description       |
| ----------- | --------- |
| application | Application window.|
| system      | System window.|

## AccessibilityExtensionContext.setTargetBundleName

setTargetBundleName(targetNames: Array\<string>): Promise\<void>;

Sets the concerned target bundle.

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

**Parameters**

| Name        | Type               | Mandatory  | Description      |
| ----------- | ------------------- | ---- | -------- |
| targetNames | Array&lt;string&gt; | Yes   | Name of the target bundle.|

**Return value**

| Type                    | Description                   |
| ---------------------- | --------------------- |
| Promise&lt;boolean&gt; | Promise used to return the result.|

**Example**

```ts
this.context.setTargetBundleName(['com.ohos.mms']);
```

## AccessibilityExtensionContext.getFocusElement

getFocusElement(isAccessibilityFocus?: boolean): Promise\<AccessibilityElement>;

Obtains the focus element.

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

**Parameters**

| Name                 | Type   | Mandatory  | Description                 |
| -------------------- | ------- | ---- | ------------------- |
| isAccessibilityFocus | boolean | No   | Whether the obtained focus element is an accessibility focus. The default value is **false**.|

**Return value**

| Type                                 | Description                    |
| ----------------------------------- | ---------------------- |
| Promise&lt;AccessibilityElement&gt; | Promise used to return the current focus element.|

**Example**

```ts
this.context.getFocusElement().then(focusElement => {
    console.log("AxExtensionAbility getFocusElement success");
})
```

## AccessibilityExtensionContext.getWindowRootElement

getWindowRootElement(windowId?: number): Promise\<AccessibilityElement>;

Obtains the root element of a window.

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

**Parameters**

| Name     | Type  | Mandatory  | Description                         |
| -------- | ------ | ---- | --------------------------- |
| windowId | number | No   | Window for which you want to obtain the root element. If this parameter is not specified, it indicates the current active window.|

**Return value**

| Type                                 | Description                     |
| ----------------------------------- | ----------------------- |
| Promise&lt;AccessibilityElement&gt; | Promise used to return the root element.|

**Example**

```ts
this.context.getWindowRootElement().then(rootElement => {
    console.log("AxExtensionAbility getWindowRootElement success");
})
```

## AccessibilityExtensionContext.getWindows

getWindows(displayId?: number): Promise<Array\<AccessibilityElement>>;

Obtains the list of windows visible to users.

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

**Parameters**

| Name      | Type  | Mandatory  | Description                       |
| --------- | ------ | ---- | ------------------------- |
| displayId | number | No   | Screen from which the window information is obtained. If this parameter is not specified, it indicates the default home screen.|

**Return value**

| Type                                      | Description                      |
| ---------------------------------------- | ------------------------ |
| Promise&lt;Array&lt;AccessibilityElement&gt;&gt; | Promise used to return the window list. |

**Example**

```ts
this.context.getWindows().then(windows => {
    console.log("AxExtensionAbility getWindows success");
})
```

## AccessibilityExtensionContext.injectGesture

injectGesture(gesturePath: GesturePath, callback: AsyncCallback\<void>): void

Injects a gesture.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| gesturePath | [GesturePath](js-apis-application-AccessibilityExtensionAbility.md#GesturePath) | Yes   | Path of the gesture to inject.    |
| callback    | AsyncCallback&lt;void&gt;                  | Yes   | Callback used to return the result.|

**Example**

```ts
let gesturePath = new GesturePath(100);
for (let i = 0; i < 10; i++) {
    let gesturePoint = new GesturePosition(100, i * 200);
    gesturePath.positions.push(gesturePoint);
}
this.context.gestureInject(gesturePath, (result) => {
    console.info('gestureInject result: ' + result);
})
```
## AccessibilityElement.attributeNames

attributeNames\<T extends keyof ElementAttributeValues>(): Promise\<Array\<T>>;

Obtains all attribute names of this element.

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

**Return value**

| Type                                      | Description                      |
| ---------------------------------------- | ------------------------ |
| Promise&lt;Array&lt;T&gt;&gt; | Promise used to return all attribute names of the element.|

**Example**

```ts
let accessibilityElement;
try {
    accessibilityElement.attributeNames().then((values) => {
        console.log("get attribute names success");
    }).catch((err) => {
        console.log("get attribute names err: "  + JSON.stringify(err));
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}
```

## AccessibilityElement.attributeValue

attributeValue\<T extends keyof ElementAttributeValues>(attributeName: T): Promise\<ElementAttributeValues[T]>;

Obtains the attribute value based on an attribute name.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| attributeName | T | Yes   | Attribute name.    |

**Return value**

| Type                                      | Description                      |
| ---------------------------------------- | ------------------------ |
| Promise&lt;Array&lt;ElementAttributeValues[T]&gt;&gt; | Promise used to return the attribute value.|

**Example**

```ts
let accessibilityElement;
try {
    let attributeName = 'name';
    accessibilityElement.attributeValue(attributeName).then((value) => {
        console.log("get attribute value by name success");
    }).catch((err) => {
        console.log("get attribute value by name err: "  + JSON.stringify(err));
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}
```

## AccessibilityElement.actionNames

actionNames(): Promise\<Array\<string>>;

Obtains the names of all actions supported by this element.

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

**Return value**

| Type                                      | Description                      |
| ---------------------------------------- | ------------------------ |
| Promise&lt;Array&lt;string&gt;&gt; | Promise used to return the names of all actions supported by the element.|

**Example**

```ts
let accessibilityElement;
try {
    accessibilityElement.actionNames().then((values) => {
        console.log("get action names success");
    }).catch((err) => {
        console.log("get action names err: "  + JSON.stringify(err));
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}
```

## AccessibilityElement.performAction

performAction(actionName: string, parameters?: object): Promise\<boolean>;

Performs an action based on the specified action name.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| actionName | string | Yes   | Action name.    |
| parameters | object | No   | Parameter required for performing the target action.    |

**Return value**

| Type                                      | Description                      |
| ---------------------------------------- | ------------------------ |
| Promise&lt;Array&lt;boolean&gt;&gt; | Promise used to return the result.|

**Example**

```ts
let accessibilityElement;
try {

    accessibilityElement.performAction('action').then((result) => {
        console.info('perform action result: ' + result);
    }).catch((err) => {
        console.log("perform action err: "  + JSON.stringify(err));
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}
```

## AccessibilityElement.findElement

findElement(type: 'content', condition: string): Promise\<Array\<AccessibilityElement>>;

Queries the information about this element based on the specified information type and condition.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| type | string | Yes   | Information type. The value is fixed at **'content'**.    |
| condition | string | Yes   | Search criteria.    |

**Return value**

| Type                                      | Description                      |
| ---------------------------------------- | ------------------------ |
| Promise&lt;Array&lt;T&gt;&gt; | Promise used to return the result.|

**Example**

```ts
let accessibilityElement;
try {
    let condition = 'keyword';
    accessibilityElement.findElement('content', condition).then((values) => {
        console.log("find element success");
    }).catch((err) => {
        console.log("find element err: "  + JSON.stringify(err));
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}
```