js-apis-inner-application-accessibilityExtensionContext.md

# AccessibilityExtensionContext (Accessibility Extension Context)

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**.

```ts
import AccessibilityExtensionAbility from '@ohos.application.AccessibilityExtensionAbility';
let axContext;
class EntryAbility extends AccessibilityExtensionAbility {
    onConnect(): void {
        console.log('AxExtensionAbility onConnect');
        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. This API uses a promise to return the result.

**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;void&gt; | Promise that returns no value.|

**Example**

```ts
let targetNames = ['com.ohos.xyz'];
try {
    axContext.setTargetBundleName(targetNames).then(() => {
        console.info('set target bundle names success');
    }).catch((err) => {
        console.error('failed to set target bundle names, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to set target bundle names, because ${JSON.stringify(exception)}');
};
```

## AccessibilityExtensionContext.setTargetBundleName

setTargetBundleName(targetNames: Array\<string>, callback: AsyncCallback\<void>): void;

Sets the concerned target bundle. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type               | Mandatory  | Description      |
| ----------- | ------------------- | ---- | -------- |
| targetNames | Array&lt;string&gt; | Yes   | Name of the target bundle.|
| callback    | AsyncCallback&lt;void&gt; | Yes   | Callback used to return the result. If the operation fails, **error** that contains data is returned.|

**Example**

```ts
let targetNames = ['com.ohos.xyz'];
try {
    axContext.setTargetBundleName(targetNames, (err, data) => {
        if (err) {
            console.error('failed to set target bundle names, because ${JSON.stringify(err)}');
            return;
        }
        console.info('set target bundle names success');
    });
} catch (exception) {
    console.error('failed to set target bundle names, because ${JSON.stringify(exception)}');
};
```

## AccessibilityExtensionContext.getFocusElement

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

Obtains the focus element. This API uses a promise to return the result.

**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.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let focusElement;
try {
    axContext.getFocusElement().then((data) => {
        focusElement = data;
        console.log('get focus element success');
    }).catch((err) => {
        console.error('failed to get focus element, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to get focus element, because ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.getFocusElement

getFocusElement(callback: AsyncCallback\<AccessibilityElement>): void;

Obtains the focus element. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback    | AsyncCallback&lt;AccessibilityElement&gt; | Yes   | Callback used to return the current focus element.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let focusElement;
try {
    axContext.getFocusElement((err, data) => {
        if (err) {
            console.error('failed to get focus element, because ${JSON.stringify(err)}');
            return;
        }
        focusElement = data;
        console.info('get focus element success');
    });
} catch (exception) {
    console.error('failed to get focus element, because ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.getFocusElement

getFocusElement(isAccessibilityFocus: boolean, callback: AsyncCallback\<AccessibilityElement>): void;

Obtains the focus element. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name                 | Type   | Mandatory  | Description                 |
| -------------------- | ------- | ---- | ------------------- |
| isAccessibilityFocus | boolean | Yes   | Whether the obtained focus element is an accessibility focus.|
| callback    | AsyncCallback&lt;AccessibilityElement&gt; | Yes   | Callback used to return the current focus element.|

**Example**

```ts
let focusElement;
let isAccessibilityFocus = true;
try {
    axContext.getFocusElement(isAccessibilityFocus, (err, data) => {
    if (err) {
        console.error('failed to get focus element, because ${JSON.stringify(err)}');
        return;
    }
    focusElement = data;
    console.info('get focus element success');
});
} catch (exception) {
    console.error('failed to get focus element, because ${JSON.stringify(exception)}');
}
```
## AccessibilityExtensionContext.getWindowRootElement

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

Obtains the root element of a window. This API uses a promise to return the result.

**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.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let rootElement;
try {
    axContext.getWindowRootElement().then((data) => {
        rootElement = data;
        console.log('get root element of the window success');
    }).catch((err) => {
        console.error('failed to get root element of the window, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to get root element of the window, ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.getWindowRootElement

getWindowRootElement(callback: AsyncCallback\<AccessibilityElement>): void;

Obtains the root element of a window. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback    | AsyncCallback&lt;AccessibilityElement&gt; | Yes   | Callback used to return the root element.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let rootElement;
try {
    axContext.getWindowRootElement((err, data) => {
    if (err) {
        console.error('failed to get root element of the window, because ${JSON.stringify(err)}');
        return;
    }
    rootElement = data;
    console.info('get root element of the window success');
});
} catch (exception) {
    console.error('failed to get root element of the window, because ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.getWindowRootElement

getWindowRootElement(windowId: number, callback: AsyncCallback\<AccessibilityElement>): void;

Obtains the root element of a window. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name                 | Type   | Mandatory  | Description                 |
| -------------------- | ------- | ---- | ------------------- |
| windowId | number | Yes   | Window for which you want to obtain the root element. If this parameter is not specified, it indicates the current active window.|
| callback    | AsyncCallback&lt;AccessibilityElement&gt; | Yes   | Callback used to return the root element.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let rootElement;
let windowId = 10;
try {
    axContext.getWindowRootElement(windowId, (err, data) => {
    if (err) {
        console.error('failed to get root element of the window, because ${JSON.stringify(err)}');
        return;
    }
    rootElement = data;
    console.info('get root element of the window success');
});
} catch (exception) {
    console.error('failed to get root element of the window, because ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.getWindows

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

Obtains the list of windows on a display. This API uses a promise to return the result.

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

**Parameters**

| Name                 | Type   | Mandatory  | Description                 |
| -------------------- | ------- | ---- | ------------------- |
| displayId | number | No   | ID of the display from which the window information is obtained. If this parameter is not specified, it indicates the default main display.|

**Return value**

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

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let windows;
try {
    axContext.getWindows().then((data) => {
        windows = data;
        console.log('get windows success');
    }).catch((err) => {
        console.error('failed to get windows, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to get windows, because ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.getWindows

getWindows(callback: AsyncCallback\<Array\<AccessibilityElement>>): void;

Obtains the list of windows on a display. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback    | AsyncCallback&lt;Array&lt;AccessibilityElement&gt;&gt; | Yes   | Callback used to return the window list.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let windows;
try {
    axContext.getWindows((err, data) => {
        if (err) {
            console.error('failed to get windows, because ${JSON.stringify(err)}');
            return;
        }
        windows = data;
        console.info('get windows success');
    });
} catch (exception) {
    console.error('failed to get windows, because ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.getWindows

getWindows(displayId: number, callback: AsyncCallback\<Array\<AccessibilityElement>>): void;

Obtains the list of windows on a display. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name                 | Type   | Mandatory  | Description                 |
| -------------------- | ------- | ---- | ------------------- |
| displayId | number | Yes   | ID of the display from which the window information is obtained. If this parameter is not specified, it indicates the default main display.|
| callback    | AsyncCallback&lt;Array&lt;AccessibilityElement&gt;&gt; | Yes   | Callback used to return the window list.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
let windows;
let displayId = 10;
try {
    axContext.getWindows(displayId, (err, data) => {
        if (err) {
            console.error('failed to get windows, because ${JSON.stringify(err)}');
            return;
        }
        windows = data;
        console.info('get windows success');
    });
} catch (exception) {
    console.error('failed to get windows, because ${JSON.stringify(exception)}');
}
```

## AccessibilityExtensionContext.injectGesture

injectGesture(gesturePath: GesturePath): Promise\<void>;

Inject a gesture. This API uses a promise to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| gesturePath | [GesturePath](js-apis-accessibility-GesturePath.md#gesturepath) | Yes   | Path of the gesture to inject.    |

**Return value**

| Type                                 | Description                    |
| ----------------------------------- | ---------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
import GesturePath from '@ohos.accessibility.GesturePath';
import GesturePoint from '@ohos.accessibility.GesturePoint';
let gesturePath = new GesturePath.GesturePath(100);
try {
    for (let i = 0; i < 10; i++) {
        let gesturePoint = new GesturePoint.GesturePoint(100, i * 200);
        gesturePath.points.push(gesturePoint);
    }
    axContext.injectGesture(gesturePath).then(() => {
        console.info('inject gesture success');
    }).catch((err) => {
        console.error('failed to inject gesture, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to inject gesture, because ${JSON.stringify(exception)}');
}
```
## AccessibilityExtensionContext.injectGesture

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

Inject a gesture. This API uses an asynchronous callback to return the result.

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

**Parameters**

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

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300003 | Do not have accessibility right for this operation. |

**Example**

```ts
import GesturePath from '@ohos.accessibility.GesturePath';
import GesturePoint from '@ohos.accessibility.GesturePoint';
let gesturePath = new GesturePath.GesturePath(100);
try {
    for (let i = 0; i < 10; i++) {
        let gesturePoint = new GesturePoint.GesturePoint(100, i * 200);
        gesturePath.points.push(gesturePoint);
    }
    axContext.injectGesture(gesturePath, (err, data) => {
        if (err) {
            console.error('failed to inject gesture, because ${JSON.stringify(err)}');
            return;
        }
        console.info('inject gesture success');
    });
} catch (exception) {
    console.error('failed to inject gesture, because ${JSON.stringify(exception)}');
}
```
## AccessibilityElement<sup>9+</sup>

Defines the accessibilityelement. Before calling APIs of **AccessibilityElement**, you must call [AccessibilityExtensionContext.getFocusElement()](#accessibilityextensioncontextgetfocuselement) or [AccessibilityExtensionContext.getWindowRootElement()](#accessibilityextensioncontextgetwindowrootelement) to obtain an **AccessibilityElement** instance.

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

## attributeNames

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

Obtains all attribute names of this element. This API uses a promise to return the result.

**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 rootElement;
let attributeNames;
rootElement.attributeNames().then((data) => {
    console.log('get attribute names success');
    attributeNames = data;
}).catch((err) => {
    console.log('failed to get attribute names, because ${JSON.stringify(err)}');
});
```
## attributeNames

attributeNames\<T extends keyof ElementAttributeValues>(callback: AsyncCallback\<Array\<T>>): void;

Obtains all attribute names of this element. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| callback    | AsyncCallback&lt;Array&lt;T&gt;&gt;                  | Yes   | Callback used to return all attribute names of the element.|

**Example**

```ts
let rootElement;
let attributeNames;
rootElement.attributeNames((err, data) => {
    if (err) {
        console.error('failed to get attribute names, because ${JSON.stringify(err)}');
        return;
    }
    attributeNames = data;
    console.info('get attribute names success');
});
```
## AccessibilityElement.attributeValue

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

Obtains the attribute value based on an attribute name. This API uses a promise to return the result.

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

**Parameters**

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

**Return value**

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

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300004 | This property does not exist. |

**Example**

```ts
let attributeName = 'name';
let attributeValue;
let rootElement;
try {
    rootElement.attributeValue(attributeName).then((data) => {
        console.log('get attribute value by name success');
        attributeValue = data;
    }).catch((err) => {
        console.error('failed to get attribute value, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to get attribute value, because ${JSON.stringify(exception)}');
}
```
## AccessibilityElement.attributeValue

attributeValue\<T extends keyof ElementAttributeValues>(attributeName: T, 
    callback: AsyncCallback\<ElementAttributeValues[T]>): void;

Obtains the attribute value based on an attribute name. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| attributeName | T | Yes   | Attribute name.    |
| callback    | AsyncCallback&lt;ElementAttributeValues[T]&gt;   | Yes   | Callback used to return the attribute value.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300004 | This property does not exist. |

**Example**

```ts
let rootElement;
let attributeValue;
let attributeName = 'name';
try {
    rootElement.attributeValue(attributeName, (err, data) => {
        if (err) {
            console.error('failed to get attribute value, because ${JSON.stringify(err)}');
            return;
        }
        attributeValue = data;
        console.info('get attribute value success');
    });
} catch (exception) {
    console.error('failed to get attribute value, because ${JSON.stringify(exception)}');
}
```
## actionNames

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

Obtains the names of all actions supported by this element. This API uses a promise to return the result.

**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 rootElement;
let actionNames;
rootElement.actionNames().then((data) => {
    console.log('get action names success');
    actionNames = data;
}).catch((err) => {
    console.error('failed to get action names because ${JSON.stringify(err)}');
});
```
## actionNames

actionNames(callback: AsyncCallback\<Array\<string>>): void;

Obtains the names of all actions supported by this element. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| callback    | AsyncCallback&lt;Array&lt;string&gt;&gt;   | Yes   | Callback used to return the names of all actions supported by the element.|

**Example**

```ts
let rootElement;
let actionNames;
rootElement.actionNames((err, data) => {
    if (err) {
        console.error('failed to get action names, because ${JSON.stringify(err)}');
        return;
    }
    actionNames = data;
    console.info('get action names success');
});
```
## performAction

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

Performs an action based on the specified action name. This API uses a promise to return the result.

**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;void&gt; | Promise that returns no value.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300005 | This action is not supported. |

**Example**

```ts
let rootElement;
try {
    rootElement.performAction('action').then((data) => {
        console.info('perform action success');
    }).catch((err) => {
        console.error('failed to perform action, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to perform action, because ${JSON.stringify(exception)}');
}
```
## performAction

performAction(actionName: string, callback: AsyncCallback\<void>): void;

Performs an action based on the specified action name. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| actionName | string | Yes   | Attribute name.    |
| callback | AsyncCallback&lt;void&gt; | Yes   | Callback used to return the result.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300005 | This action is not supported. |

**Example**

```ts
let rootElement;
try {
    rootElement.performAction('action', (err, data) => {
        if (err) {
            console.error('failed to perform action, because ${JSON.stringify(err)}');
            return;
        }
        console.info('perform action success');
    });
} catch (exception) {
    console.error('failed to perform action, because ${JSON.stringify(exception)}');
}
```
## performAction

performAction(actionName: string, parameters: object, callback: AsyncCallback\<void>): void;

Performs an action based on the specified action name. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| actionName | string | Yes   | Action name.    |
| parameters | object | Yes   | Parameter required for performing the target action.    |
| callback | AsyncCallback&lt;void&gt; | Yes   | Callback used to return the result.|

**Error codes**

For details about the error codes, see [Accessibility Error Codes](../errorcodes/errorcode-accessibility.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 9300005 | This action is not supported. |

**Example**

```ts
let rootElement;
let actionName = 'action';
let parameters = {
    'setText': 'test text'
};
try {
    rootElement.performAction(actionName, parameters, (err, data) => {
        if (err) {
            console.error('failed to perform action, because ${JSON.stringify(err)}');
            return;
        }
        console.info('perform action success');
    });
} catch (exception) {
    console.error('failed to perform action, because ${JSON.stringify(exception)}');
}
```
## findElement('content')

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

Queries the element information of the **content** type. This API uses a promise to return the result.

**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;AccessibilityElement&gt;&gt; | Promise used to return the result.|

**Example**

```ts
let rootElement;
let type = 'content';
let condition = 'keyword';
let elements;
try {
    rootElement.findElement(type, condition).then((data) => {
        elements = data;
        console.log('find element success');
    }).catch((err) => {
        console.error('failed to find element, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to find element, because ${JSON.stringify(exception)}');
}
```
## findElement('content')

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

Queries the element information of the **content** type. This API uses an asynchronous callback to return the result.

**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.    |
| callback | AsyncCallback&lt;Array&lt;AccessibilityElement&gt;&gt; | Yes   | Callback used to return the result.|

**Example**

```ts
let rootElement;
let type = 'content';
let condition = 'keyword';
let elements;
try {
    rootElement.findElement(type, condition, (err, data) => {
        if (err) {
            console.error('failed to find element, because ${JSON.stringify(err)}');
            return;
        }
        elements = data;
        console.info('find element success');
    });
} catch (exception) {
    console.error('failed to find element, because ${JSON.stringify(exception)}');
}
```
## findElement('focusType')

findElement(type: 'focusType', condition: FocusType): Promise\<AccessibilityElement>;

Queries the element information of the **focusType** type. This API uses a promise to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| type | string | Yes   | Information type. The value is fixed at **'focusType'**.    |
| condition | [FocusType](#focustype) | Yes   | Enumerates the focus types.    |

**Return value**

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

**Example**

```ts
let rootElement;
let type = 'focusType';
let condition = 'normal';
let element;
try {
    rootElement.findElement(type, condition).then((data) => {
        element = data;
        console.log('find element success');
    }).catch((err) => {
        console.error('failed to find element, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to find element, because ${JSON.stringify(exception)}');
}
```
## findElement('focusType')

findElement(type: 'focusType', condition: FocusType, callback: AsyncCallback\<AccessibilityElement>): void;

Queries the element information of the **focusType** type. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| type | string | Yes   | Information type. The value is fixed at **'focusType'**.    |
| condition | [FocusType](#focustype) | Yes   | Enumerates the focus types.    |
| callback | AsyncCallback&lt;AccessibilityElement&gt; | Yes   | Callback used to return the result.|

**Example**

```ts
let rootElement;
let type = 'focusType';
let condition = 'normal';
let element;
try {
    rootElement.findElement(type, condition, (err, data) => {
        if (err) {
            console.error('failed to find element, because ${JSON.stringify(err)}');
            return;
        }
        element = data;
        console.info('find element success');
    });
} catch (exception) {
    console.error('failed to find element, because ${JSON.stringify(exception)}');
}
```
## findElement('focusDirection')

findElement(type: 'focusDirection', condition: FocusDirection): Promise\<AccessibilityElement>;

Queries the element information of the **focusDirection** type. This API uses a promise to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| type | string | Yes   | Information type. The value is fixed at **'focusDirection'**.    |
| condition | [FocusDirection](#focusdirection) | Yes   | Enumerates the focus directions.    |

**Return value**

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

**Example**

```ts
let rootElement;
let type = 'focusDirection';
let condition = 'up';
let element;
try {
    rootElement.findElement(type, condition).then((data) => {
        element = data;
        console.log('find element success');
    }).catch((err) => {
        console.error('failed to find element, because ${JSON.stringify(err)}');
    });
} catch (exception) {
    console.error('failed to find element, because ${JSON.stringify(exception)}');
}
```
## findElement('focusDirection')

findElement(type: 'focusDirection', condition: FocusDirection, callback: AsyncCallback\<AccessibilityElement>): void;

Queries the element information of the **focusDirection** type. This API uses an asynchronous callback to return the result.

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

**Parameters**

| Name        | Type                                    | Mandatory  | Description            |
| ----------- | ---------------------------------------- | ---- | -------------- |
| type | string | Yes   | Information type. The value is fixed at **'focusDirection'**.    |
| condition | [FocusDirection](#focusdirection) | Yes   | Direction of the next focus element.    |
| callback | AsyncCallback&lt;AccessibilityElement&gt; | Yes   | Callback used to return the result.|

**Example**

```ts
let rootElement;
let type = 'focusDirection';
let condition = 'up';
let elements;
try {
    rootElement.findElement(type, condition, (err, data) => {
        if (err) {
            console.error('failed to find element, because ${JSON.stringify(err)}');
            return;
        }
        elements = data;
        console.info('find element success');
    });
} catch (exception) {
    console.error('failed to find element, because ${JSON.stringify(exception)}');
}
```