xref: /docs/en/application-dev/reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext-sys.md

# UIAbilityContext (System API)

**UIAbilityContext**, inherited from [Context](js-apis-inner-application-context.md), provides the context environment for [UIAbility](js-apis-app-ability-uiAbility.md) that needs to store its status. **UIAbilityContext** provides UIAbility-related configuration and APIs for operating UIAbilities and ServiceExtensionAbilities. For example, you can use the APIs to start a UIAbility, terminate a UIAbility to which the UIAbilityContext belongs, and start, terminate, connect to, or disconnect from a ServiceExtensionAbility.

> **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.
>  - The APIs provided by this module are system APIs.

## Modules to Import

```ts
import { common } from '@kit.AbilityKit';
```

> **NOTE**
>
> In the sample code provided in this topic, **this.context** is used to obtain **UIAbilityContext**, where **this** indicates a UIAbility instance inherited from **UIAbility**. To use **UIAbilityContext** APIs on pages, see [Obtaining the Context of UIAbility](../../application-models/uiability-usage.md#obtaining-the-context-of-uiability).

## UIAbilityContext.startAbilityForResultWithAccount

startAbilityForResultWithAccount(want: Want, accountId: number, callback: AsyncCallback\<AbilityResult>): void

Starts an ability with the account ID specified and returns the result when the ability is terminated. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| callback | AsyncCallback&lt;[AbilityResult](js-apis-inner-ability-abilityResult.md)&gt; | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, common, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let accountId = 100;

    try {
      this.context.startAbilityForResultWithAccount(want, accountId, (err: BusinessError, result: common.AbilityResult) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`startAbilityForResultWithAccount failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startAbilityForResultWithAccount succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startAbilityForResultWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```


## UIAbilityContext.startAbilityForResultWithAccount

startAbilityForResultWithAccount(want: Want, accountId: number, options: StartOptions, callback: AsyncCallback\<void\>): void

Starts an ability with the account ID and start options specified and returns the result when the ability is terminated. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | Yes| Parameters used for starting the ability.|
| callback | AsyncCallback\<void\> | Yes| Callback invoked when the ability is terminated.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, StartOptions, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let accountId = 100;
    let options: StartOptions = {
      displayId: 0
    };

    try {
      this.context.startAbilityForResultWithAccount(want, accountId, options, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`startAbilityForResultWithAccount failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startAbilityForResultWithAccount succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startAbilityForResultWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```


## UIAbilityContext.startAbilityForResultWithAccount

startAbilityForResultWithAccount(want: Want, accountId: number, options?: StartOptions): Promise\<AbilityResult\>

Starts an ability with the account ID specified and returns the result when the ability is terminated. This API uses a promise to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | No| Parameters used for starting the ability.|

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;[AbilityResult](js-apis-inner-ability-abilityResult.md)&gt; | Promise used to return the ability result when the ability is terminated.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, StartOptions, Want, common } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let accountId = 100;
    let options: StartOptions = {
      displayId: 0
    };

    try {
      this.context.startAbilityForResultWithAccount(want, accountId, options)
        .then((result: common.AbilityResult) => {
          // Carry out normal service processing.
          console.info('startAbilityForResultWithAccount succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`startAbilityForResultWithAccount failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startAbilityForResultWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```
## UIAbilityContext.startServiceExtensionAbility

startServiceExtensionAbility(want: Want, callback: AsyncCallback\<void>): void

Starts a ServiceExtensionAbility. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ServiceExtensionAbility.|
| callback | AsyncCallback\<void\> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };

    try {
      this.context.startServiceExtensionAbility(want, (error: BusinessError) => {
        if (error.code) {
          // Process service logic errors.
          console.error(`startServiceExtensionAbility failed, code is ${error.code}, message is ${error.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startServiceExtensionAbility succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startServiceExtensionAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.startServiceExtensionAbility

startServiceExtensionAbility(want: Want): Promise\<void>

Starts a ServiceExtensionAbility. This API uses a promise to return the result.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ServiceExtensionAbility.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };

    try {
      this.context.startServiceExtensionAbility(want)
        .then(() => {
          // Carry out normal service processing.
          console.info('startServiceExtensionAbility succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`startServiceExtensionAbility failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startServiceExtensionAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.startServiceExtensionAbilityWithAccount

startServiceExtensionAbilityWithAccount(want: Want, accountId: number, callback: AsyncCallback\<void>): void

Starts a ServiceExtensionAbility with the account ID specified. This API uses an asynchronous callback to return the result.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ServiceExtensionAbility.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| callback | AsyncCallback\<void\> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };
    let accountId = 100;

    try {
      this.context.startServiceExtensionAbilityWithAccount(want, accountId, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`startServiceExtensionAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startServiceExtensionAbilityWithAccount succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startServiceExtensionAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.startServiceExtensionAbilityWithAccount

startServiceExtensionAbilityWithAccount(want: Want, accountId: number): Promise\<void>

Starts a ServiceExtensionAbility with the account ID specified. This API uses a promise to return the result.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };
    let accountId = 100;

    try {
      this.context.startServiceExtensionAbilityWithAccount(want, accountId)
        .then(() => {
          // Carry out normal service processing.
          console.info('startServiceExtensionAbilityWithAccount succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`startServiceExtensionAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startServiceExtensionAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```
## UIAbilityContext.stopServiceExtensionAbility

stopServiceExtensionAbility(want: Want, callback: AsyncCallback\<void>): void

Stops a ServiceExtensionAbility in the same application. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ServiceExtensionAbility.|
| callback | AsyncCallback\<void\> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };

    try {
      this.context.stopServiceExtensionAbility(want, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`stopServiceExtensionAbility failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('stopServiceExtensionAbility succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`stopServiceExtensionAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.stopServiceExtensionAbility

stopServiceExtensionAbility(want: Want): Promise\<void>

Stops a ServiceExtensionAbility in the same application. This API uses a promise to return the result.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ServiceExtensionAbility.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000011 | The context does not exist. |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };

    try {
      this.context.stopServiceExtensionAbility(want)
        .then(() => {
          // Carry out normal service processing.
          console.info('stopServiceExtensionAbility succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`stopServiceExtensionAbility failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`stopServiceExtensionAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.stopServiceExtensionAbilityWithAccount

stopServiceExtensionAbilityWithAccount(want: Want, accountId: number, callback: AsyncCallback\<void>): void

Stops a ServiceExtensionAbility with the account ID specified in the same application. This API uses an asynchronous callback to return the result.

> **NOTE**
>
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ServiceExtensionAbility.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| callback | AsyncCallback\<void\> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000011 | The context does not exist. |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };
    let accountId = 100;

    try {
      this.context.stopServiceExtensionAbilityWithAccount(want, accountId, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`stopServiceExtensionAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('stopServiceExtensionAbilityWithAccount succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`stopServiceExtensionAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.stopServiceExtensionAbilityWithAccount

stopServiceExtensionAbilityWithAccount(want: Want, accountId: number): Promise\<void>

Stops a ServiceExtensionAbility with the account ID specified in the same application. This API uses a promise to return the result.

> **NOTE**
>
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ServiceExtensionAbility.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000011 | The context does not exist. |
| 16000050 | Internal error. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };
    let accountId = 100;

    try {
      this.context.stopServiceExtensionAbilityWithAccount(want, accountId)
        .then(() => {
          // Carry out normal service processing.
          console.info('stopServiceExtensionAbilityWithAccount succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`stopServiceExtensionAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`stopServiceExtensionAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.connectServiceExtensionAbilityWithAccount

connectServiceExtensionAbilityWithAccount(want: Want, accountId: number, options: ConnectOptions): number

Connects this ability to a ServiceExtensionAbility, with the account ID specified. This API can be called only by the main thread.

Currently, this API takes effect only on mobile phones and tablets.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| options | [ConnectOptions](js-apis-inner-ability-connectOptions.md) | Yes| Instance of the callback function after the connection to the ServiceExtensionAbility is set up.|

**Return value**

| Type| Description|
| -------- | -------- |
| number | Result code of the ability connection.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000011 | The context does not exist.        |
| 16000050 | Internal error. |

**Example**

```ts
import { UIAbility, Want, common } from '@kit.AbilityKit';
import { rpc } from '@kit.IPCKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'ServiceExtensionAbility'
    };
    let accountId = 100;
    let commRemote: rpc.IRemoteObject;
    let options: common.ConnectOptions = {
      onConnect(elementName, remote) {
        commRemote = remote;
        console.info('onConnect...');
      },
      onDisconnect(elementName) {
        console.info('onDisconnect...');
      },
      onFailed(code) {
        console.info('onFailed...');
      }
    };
    let connection: number;

    try {
      connection = this.context.connectServiceExtensionAbilityWithAccount(want, accountId, options);
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`connectServiceExtensionAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.startAbilityWithAccount

startAbilityWithAccount(want: Want, accountId: number, callback: AsyncCallback\<void\>): void

Starts an ability with want and the account ID specified. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| callback | AsyncCallback\<void\> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let accountId = 100;

    try {
      this.context.startAbilityWithAccount(want, accountId, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`startAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startAbilityWithAccount succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```


## UIAbilityContext.startAbilityWithAccount

startAbilityWithAccount(want: Want, accountId: number, options: StartOptions, callback: AsyncCallback\<void\>): void

Starts an ability with want, the account ID, and start options specified. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | Yes| Parameters used for starting the ability.|
| callback | AsyncCallback\<void\> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want, StartOptions } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let accountId = 100;
    let options: StartOptions = {
      displayId: 0
    };

    try {
      this.context.startAbilityWithAccount(want, accountId, options, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`startAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startAbilityWithAccount succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```


## UIAbilityContext.startAbilityWithAccount

startAbilityWithAccount(want: Want, accountId: number, options?: StartOptions): Promise\<void\>

Starts an ability with want, the account ID, and start options specified. This API uses a promise to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).
> Permission verification is not required when **accountId** specifies the current user.

**Required permissions**: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| accountId | number | Yes| ID of a system account. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | No| Parameters used for starting the ability.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000019 | No matching ability is found. |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want, StartOptions } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let accountId = 100;
    let options: StartOptions = {
      displayId: 0
    };

    try {
      this.context.startAbilityWithAccount(want, accountId, options)
        .then(() => {
          // Carry out normal service processing.
          console.info('startAbilityWithAccount succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`startAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.setMissionIcon

setMissionIcon(icon: image.PixelMap, callback: AsyncCallback\<void>): void

Sets an icon for this ability in the mission. This API uses an asynchronous callback to return the result. The maximum size of the icon is 600 MB.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| icon | image.PixelMap | Yes| Icon of the ability to set.|
| callback | AsyncCallback\<void> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000011 | The context does not exist. |
| 16000050 | Internal error. |

**Example**

```ts
import { UIAbility } from '@kit.AbilityKit';
import { image } from '@kit.ImageKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let imagePixelMap: image.PixelMap;
    let color = new ArrayBuffer(0);
    image.createPixelMap(color, {
      size: {
        height: 100,
        width: 100
      }
    }).then((data) => {
      imagePixelMap = data;
      this.context.setMissionIcon(imagePixelMap, (err: BusinessError) => {
        console.error(`setMissionLabel failed, code is ${err.code}, message is ${err.message}`);
      })
    }).catch((err: BusinessError) => {
      console.error(`createPixelMap failed, code is ${err.code}, message is ${err.message}`);
    });
  }
}
```


## UIAbilityContext.setMissionIcon

setMissionIcon(icon: image.PixelMap): Promise\<void>

Sets an icon for this ability in the mission. This API uses a promise to return the result. The maximum size of the icon is 600 MB.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| icon | image.PixelMap | Yes| Icon of the ability to set.|

**Return value**

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

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000011 | The context does not exist. |
| 16000050 | Internal error. |

**Example**

```ts
import { UIAbility } from '@kit.AbilityKit';
import { image } from '@kit.ImageKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let imagePixelMap: image.PixelMap;
    let color = new ArrayBuffer(0);
    image.createPixelMap(color, {
      size: {
        height: 100,
        width: 100
      }
    }).then((data) => {
      imagePixelMap = data;
      this.context.setMissionIcon(imagePixelMap)
        .then(() => {
          console.info('setMissionIcon succeed');
        })
        .catch((err: BusinessError) => {
          console.error(`setMissionLabel failed, code is ${err.code}, message is ${err.message}`);
        });
    }).catch((err: BusinessError) => {
      console.error(`createPixelMap failed, code is ${err.code}, message is ${err.message}`);
    });
  }
}
```

## UIAbilityContext.startRecentAbility

startRecentAbility(want: Want, callback: AsyncCallback&lt;void&gt;): void

Starts an ability. If the ability has multiple instances, the latest instance is started. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| callback | AsyncCallback\<void> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |
| 16000073 | The app clone index is invalid. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };

    try {
      this.context.startRecentAbility(want, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`startRecentAbility failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startRecentAbility succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startRecentAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```
## UIAbilityContext.startRecentAbility

startRecentAbility(want: Want, options: StartOptions, callback: AsyncCallback&lt;void&gt;): void

Starts an ability with the start options specified. If the ability has multiple instances, the latest instance is started.  This API uses an asynchronous callback to return the result. It can be called only by the main thread.



> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | Yes| Parameters used for starting the ability.|
| callback | AsyncCallback\<void> | Yes| Callback used to return the result.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |
| 16000073 | The app clone index is invalid. |

**Example**

```ts
import { UIAbility, Want, StartOptions } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let options: StartOptions = {
      displayId: 0
    };

    try {
      this.context.startRecentAbility(want, options, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`startRecentAbility failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('startRecentAbility succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startRecentAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```
## UIAbilityContext.startRecentAbility

startRecentAbility(want: Want, options?: StartOptions): Promise&lt;void&gt;

Starts an ability. If the ability has multiple instances, the latest instance is started. This API uses a promise to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | No| Parameters used for starting the ability.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |
| 16000073 | The app clone index is invalid. |

**Example**

```ts
import { UIAbility, Want, StartOptions } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      bundleName: 'com.example.myapplication',
      abilityName: 'EntryAbility'
    };
    let options: StartOptions = {
      displayId: 0,
    };

    try {
      this.context.startRecentAbility(want, options)
        .then(() => {
          // Carry out normal service processing.
          console.info('startRecentAbility succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`startRecentAbility failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startRecentAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.startAbilityByCallWithAccount<sup>10+</sup>

startAbilityByCallWithAccount(want: Want, accountId: number): Promise&lt;Caller&gt;

Starts an ability with the account ID specified and obtains the caller object for communicating with the ability. This API can be called only by the main thread.

This API cannot be used to start the UIAbility with the launch type set to [specified](../../application-models/uiability-launch-type.md#specified).

Observe the following when using this API:
 - If an application needs to call this API to start an ability that belongs to another user, it must have the **ohos.permission.ABILITY_BACKGROUND_COMMUNICATION** and **ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS** permissions.
 - If an application running in the background needs to call this API to start an ability, it must have the **ohos.permission.START_ABILITIES_FROM_BACKGROUND** permission.
 - If **exported** of the target ability is **false** in cross-application scenarios, the caller must have the **ohos.permission.START_INVISIBLE_ABILITY** permission.
 - The rules for using this API in the same-device and cross-device scenarios are different. For details, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**Required permissions**: ohos.permission.ABILITY_BACKGROUND_COMMUNICATION and ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Information about the ability to start, including **abilityName**, **moduleName**, **bundleName**, **deviceId** (optional), and **parameters** (optional). If **deviceId** is left blank or null, the local ability is started. If **parameters** is left blank or null, the ability is started in the background.|
| accountId | number | Yes| ID of a system account. The value **-1** indicates the current user. For details, see [getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9).|

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;[Caller](js-apis-app-ability-uiAbility.md#caller)&gt; | Promise used to return the caller object to communicate with.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | Static permission denied. The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000011 | The context does not exist. |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16200001 | The caller has been released.        |

**Example**

```ts
import { UIAbility, Want, Caller } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let caller: Caller;
    // ID of a system account. The value -1 indicates the current user.
    let accountId = -1;
    // Specify the ability to start.
    let want: Want = {
      bundleName: 'com.acts.actscalleeabilityrely',
      moduleName: 'entry',
      abilityName: 'EntryAbility',
      deviceId: '',
      parameters: {
        // If the value of 'ohos.aafwk.param.callAbilityToForeground' is true, the ability is started in the foreground. If the value is false or not set, the ability is started in the background.
        'ohos.aafwk.param.callAbilityToForeground': true
      }
    };

    try {
      this.context.startAbilityByCallWithAccount(want, accountId)
        .then((obj: Caller) => {
          // Carry out normal service processing.
          caller = obj;
          console.log('startAbilityByCallWithAccount succeed');
        }).catch((error: BusinessError) => {
        // Process service logic errors.
        console.error(`startAbilityByCallWithAccount failed, error.code: ${error.code}, error.message: ${error.message}`);
      });
    } catch (paramError) {
      // Process input parameter errors.
      console.error(`error.code: ${paramError.code}, error.message: ${paramError.message}`);
    }
  }
}
```

## UIAbilityContext.startAbilityAsCaller<sup>10+<sup>

startAbilityAsCaller(want: Want, callback: AsyncCallback\<void>): void

Starts an ability with the caller information specified. The caller information is carried in **want** and identified at the system service layer. The ability can obtain the caller information from the **want** parameter in the **onCreate** lifecycle callback. When this API is used to start an ability, the caller information carried in **want** is not overwritten by the current application information. The system service layer can obtain the initial caller information. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md)  | Yes| Want information about the target ability.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result. If the ability is started, **err** is **undefined**. Otherwise, **err** is an error object.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden.        |
| 16000011 | The context does not exist.        |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want, AbilityConstant } from '@kit.AbilityKit';

export default class EntryAbility extends UIAbility {
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
    // want contains the information about the caller who starts the application.
    let localWant: Want = want;
    localWant.bundleName = 'com.example.demo';
    localWant.moduleName = 'entry';
    localWant.abilityName = 'TestAbility';

    // Start a new ability using the caller information.
    this.context.startAbilityAsCaller(localWant, (err) => {
      if (err && err.code != 0) {
        console.error('startAbilityAsCaller failed, err:' + JSON.stringify(err));
      } else {
        console.log('startAbilityAsCaller success.');
      }
    })
  }
}
```

## UIAbilityContext.startAbilityAsCaller<sup>10+<sup>

startAbilityAsCaller(want: Want, options: StartOptions, callback: AsyncCallback\<void>): void

Starts an ability with the caller information and start options specified. The caller information is carried in **want** and identified at the system service layer. The ability can obtain the caller information from the **want** parameter in the **onCreate** lifecycle callback. When this API is used to start an ability, the caller information carried in **want** is not overwritten by the current application information. The system service layer can obtain the initial caller information. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md)  | Yes| Want information about the target ability.|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | Yes| Parameters used for starting the ability.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result. If the ability is started, **err** is **undefined**. Otherwise, **err** is an error object.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | 401 - Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.|
| 16000001 | The specified ability does not exist. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000011 | The context does not exist.        |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want, AbilityConstant, StartOptions } from '@kit.AbilityKit';

export default class EntryAbility extends UIAbility {
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
    // want contains the information about the caller who starts the application.
    let localWant: Want = want;
    localWant.bundleName = 'com.example.demo';
    localWant.moduleName = 'entry';
    localWant.abilityName = 'TestAbility';
    let option: StartOptions = {
      displayId: 0
    };

    // Start a new ability using the caller information.
    this.context.startAbilityAsCaller(localWant, option, (err) => {
      if (err && err.code != 0) {
        console.error('startAbilityAsCaller failed, err:' + JSON.stringify(err));
      } else {
        console.log('startAbilityAsCaller success.');
      }
    })
  }
}
```

## UIAbilityContext.startAbilityAsCaller<sup>10+<sup>

startAbilityAsCaller(want: Want, options?: StartOptions): Promise\<void>

Starts an ability with the caller information specified. The caller information is carried in **want** and identified at the system service layer. The ability can obtain the caller information from the **want** parameter in the **onCreate** lifecycle callback. When this API is used to start an ability, the caller information carried in **want** is not overwritten by the current application information. The system service layer can obtain the initial caller information. This API uses a promise to return the result. It can be called only by the main thread.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md)  | Yes| Want information about the target ability.|
| options | [StartOptions](js-apis-app-ability-startOptions.md) | No| Parameters used for starting the ability.|

**Return value**

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

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed. |
| 16000001 | The specified ability does not exist. |
| 16000002 | Incorrect ability type. |
| 16000004 | Failed to start the invisible ability. |
| 16000005 | The specified process does not have the permission. |
| 16000006 | Cross-user operations are not allowed. |
| 16000008 | The crowdtesting application expires. |
| 16000009 | An ability cannot be started or stopped in Wukong mode. |
| 16000010 | The call with the continuation flag is forbidden.        |
| 16000011 | The context does not exist.        |
| 16000012 | The application is controlled.        |
| 16000013 | The application is controlled by EDM.       |
| 16000050 | Internal error. |
| 16000053 | The ability is not on the top of the UI. |
| 16000055 | Installation-free timed out. |
| 16000071 | App clone is not supported. |
| 16000072 | App clone or multi-instance is not supported. |
| 16000073 | The app clone index is invalid. |
| 16000076 | The app instance key is invalid. |
| 16000077 | The number of app instances reaches the limit. |
| 16000078 | The multi-instance is not supported. |
| 16000079 | The APP_INSTANCE_KEY cannot be specified. |
| 16000080 | Creating an instance is not supported. |
| 16000082 | The UIAbility is being started. |
| 16200001 | The caller has been released. |

**Example**

```ts
import { UIAbility, Want, AbilityConstant, StartOptions } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
    // want contains the information about the caller who starts the application.
    let localWant: Want = want;
    localWant.bundleName = 'com.example.demo';
    localWant.moduleName = 'entry';
    localWant.abilityName = 'TestAbility';
    let option: StartOptions = {
      displayId: 0
    };

    // Start a new ability using the caller information.
    this.context.startAbilityAsCaller(localWant, option)
      .then(() => {
        console.log('startAbilityAsCaller success.');
      })
      .catch((err: BusinessError) => {
        console.error('startAbilityAsCaller failed, err:' + JSON.stringify(err));
      })
  }
}
```

## UIAbilityContext.requestModalUIExtension<sup>11+<sup>

requestModalUIExtension(pickerWant: Want): Promise\<void>

Requests the specified foreground application to start the UIExtensionAbility of the corresponding type. This API uses a promise to return the result. It can be called only by the main thread.

The foreground application is specified by **bundleName** in **want.parameters**. If **bundleName** is left unspecified, or if the application specified by **bundleName** is not running in the foreground or does not exist, the UIExtensionAbility is directly started on the system UI. The UIExtensionAbility to start is determined by the combination of the **bundleName**, **abilityName**, and **moduleName** fields in **want**, and its type is determined by the **ability.want.params.uiExtensionType** field in **want.parameters**.

Before starting the UIExtensionAbility, ensure that the foreground application has finished page initialization. Otherwise, the UIExtensionAbility fails to start and the error message "uiContent is nullptr" is displayed. The application can determine the time to start the UIExtensionAbility by listening for the page loading status. After the page initialization is successful, the key log information "UIContentImpl: focus again" is recorded.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| pickerWant | [Want](js-apis-app-ability-want.md)  | Yes| Want information used to start the UIExtensionAbility.|

**Return value**

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

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000050 | Internal error. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      bundleName: 'com.example.myapplication',
      abilityName: 'com.example.myapplication.UIExtAbility',
      moduleName: 'entry_test',
      parameters: {
        'bundleName': 'com.example.myapplication',
        // The value is the same as the value of type configured for com.example.myapplication.UIExtAbility.
        'ability.want.params.uiExtensionType': 'sys/commonUI'
      }
    };

    try {
      this.context.requestModalUIExtension(want)
        .then(() => {
          // Carry out normal service processing.
          console.info('requestModalUIExtension succeed');
        })
        .catch((err: BusinessError) => {
          // Process service logic errors.
          console.error(`requestModalUIExtension failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`requestModalUIExtension failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIAbilityContext.requestModalUIExtension<sup>11+<sup>
requestModalUIExtension(pickerWant: Want, callback: AsyncCallback\<void>): void

Requests the specified foreground application to start the UIExtensionAbility of the corresponding type. This API uses an asynchronous callback to return the result. It can be called only by the main thread.

The foreground application is specified by **bundleName** in **want.parameters**. If **bundleName** is left unspecified, or if the application specified by **bundleName** is not running in the foreground or does not exist, the UIExtensionAbility is directly started on the system UI. The UIExtensionAbility to start is determined by the combination of the **bundleName**, **abilityName**, and **moduleName** fields in **want**, and its type is determined by the **ability.want.params.uiExtensionType** field in **want.parameters**.

Before starting the UIExtensionAbility, ensure that the foreground application has finished page initialization. Otherwise, the UIExtensionAbility fails to start and the error message "uiContent is nullptr" is displayed. The application can determine the time to start the UIExtensionAbility by listening for the page loading status. After the page initialization is successful, the key log information "UIContentImpl: focus again" is recorded.

> **NOTE**
>
> For details about the startup rules for the components in the stage model, see [Component Startup Rules (Stage Model)](../../application-models/component-startup-rules.md).

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**System API**: This is a system API.

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| pickerWant | [Want](js-apis-app-ability-want.md)  | Yes| Want information used to start the UIExtensionAbility.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result. If the UIExtensionAbility is started, **err** is **undefined**; otherwise, **err** is an error object.|

**Error codes**

For details about the error codes, see [Universal Error Codes](../errorcode-universal.md) and [Ability Error Codes](errorcode-ability.md).

| ID| Error Message|
| ------- | -------------------------------- |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000050 | Internal error. |

**Example**

```ts
import { UIAbility, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onForeground() {
    let want: Want = {
      bundleName: 'com.example.myapplication',
      abilityName: 'UIExtAbility',
      moduleName: 'entry_test',
      parameters: {
        'bundleName': 'com.example.myapplication',
        // The value is the same as the value of type configured for com.example.myapplication.UIExtAbility.
        'ability.want.params.uiExtensionType': 'sys/commonUI'
      }
    };

    try {
      this.context.requestModalUIExtension(want, (err: BusinessError) => {
        if (err.code) {
          // Process service logic errors.
          console.error(`requestModalUIExtension failed, code is ${err.code}, message is ${err.message}`);
          return;
        }
        // Carry out normal service processing.
        console.info('requestModalUIExtension succeed');
      });
    } catch (err) {
      // Process input parameter errors.
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`requestModalUIExtension failed, code is ${code}, message is ${message}`);
    }
  }
}
```