# UIExtensionContext (系统接口)

UIExtensionContext是[UIExtensionAbility](js-apis-app-ability-uiExtensionAbility.md)的上下文环境，继承自[ExtensionContext](js-apis-inner-application-extensionContext.md)，提供UIExtensionAbility的相关配置信息以及操作UIAbility的方法，如启动UIAbility等。

> **说明：**
>
>  - 本模块首批接口从API version 12开始支持。后续版本的新增接口，采用上角标单独标记接口的起始版本。
>  - 本模块接口仅可在Stage模型下使用。
>  - 本模块接口为系统接口。

## 导入模块

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

## UIExtensionContext.startAbilityForResultAsCaller

startAbilityForResultAsCaller(want: Want, options?: StartOptions): Promise<AbilityResult>

使用设置的caller信息启动一个Ability，caller信息由want携带，在系统服务层识别，Ability可以在onCreate生命周期的want参数中获取到caller信息。使用该接口启动一个Ability时，want的caller信息不会被当前自身的应用信息覆盖，系统服务层可获取到初始caller的信息。使用Promise异步回调。

 - 正常情况下可通过调用[terminateSelfWithResult](js-apis-inner-application-uiAbilityContext.md#uiabilitycontextterminateselfwithresult)接口使之终止并且返回结果给调用方。
 - 异常情况下比如杀死Ability会返回异常信息给调用方，异常信息中resultCode为-1。
 - 如果被启动的Ability模式是单实例模式，不同应用多次调用该接口启动这个Ability，当这个Ability调用[terminateSelfWithResult](js-apis-inner-application-uiAbilityContext.md#uiabilitycontextterminateselfwithresult)接口使之终止时，只将正常结果返回给最后一个调用方，其它调用方返回异常信息，异常信息中resultCode为-1。

> **说明：**
>
> 组件启动规则详见：[组件启动规则（Stage模型）](../../application-models/component-startup-rules.md)。

**模型约束**：此接口仅可在Stage模型下使用。

**系统接口**：此接口为系统接口。

**系统能力**：SystemCapability.Ability.AbilityRuntime.Core

**参数：**

| 参数名  | 类型                                                | 必填 | 说明                      |
| ------- | --------------------------------------------------- | ---- | ------------------------- |
| want    | [Want](js-apis-app-ability-want.md)                 | 是   | 启动Ability的want信息。   |
| options | [StartOptions](js-apis-app-ability-startOptions.md) | 否   | 启动Ability所携带的参数。 |

**返回值：**

| 类型                                                         | 说明                      |
| ------------------------------------------------------------ | ------------------------- |
| Promise<[AbilityResult](js-apis-inner-ability-abilityResult.md)> | Promise对象，返回Ability结果对象。 |

**错误码：**

以下错误码详细介绍请参考[通用错误码](../errorcode-universal.md)和[元能力子系统错误码](errorcode-ability.md)。

| 错误码ID | 错误信息                                                |
| -------- | ------------------------------------------------------- |
| 401| Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |
| 16000001 | The specified ability does not exist.                   |
| 16000004 | Failed to start the invisible ability.                      |
| 16000050 | Internal error.                                         |
| 16000073 | The app clone index is invalid. |

**示例：**

```ts
import { UIExtensionAbility } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class UIExtension extends UIExtensionAbility {
  onForeground() {
    this.context.startAbilityForResultAsCaller({
      bundleName: 'com.example.startabilityforresultascaller',
      abilityName: 'EntryAbility',
      moduleName: 'entry'
    }).then((data) => {
      console.log('=======>startAbilityForResultAsCaller data Promise ======>' + JSON.stringify(data));
    }).catch((error: BusinessError) => {
      console.log('=======>startAbilityForResultAsCaller error.code Promise ======>' + error.code);
    });
  }
}
```

## UIExtensionContext.startServiceExtensionAbility<sup>18+</sup>

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

启动一个ServiceExtensionAbility。使用Promise异步回调。

**模型约束**：此接口仅可在Stage模型下使用。

**系统接口**：此接口为系统接口。

**系统能力**：SystemCapability.Ability.AbilityRuntime.Core

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| ------ | ------ | ------ | ------ |
| want | [Want](js-apis-app-ability-want.md) | 是 | 启动ServiceExtensionAbility的Want信息。 |

**返回值：**

| 类型 | 说明 |
| ------ | ------ |
| Promise&lt;void&gt; | Promise对象。无返回结果的Promise对象。 |

**错误码：**

以下错误码详细介绍请参考[通用错误码](../errorcode-universal.md)和[元能力子系统错误码](errorcode-ability.md)。

| 错误码ID | 错误信息 |
| ------ | ------ |
| 201 | The application does not have permission to call the interface. |
| 202 | The application is not system-app, can not use system-api. |
| 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. |

**示例：**

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

export default class UIExtAbility extends UIExtensionAbility {
  onForeground() {
    let want: Want = {
      bundleName: 'com.example.myapplication',
      moduleName: 'entry',
      abilityName: 'ServiceExtensionAbility'
    };

    try {
      this.context.startServiceExtensionAbility(want)
        .then(() => {
          // 执行正常业务
          console.info('startServiceExtensionAbility succeed');
        })
        .catch((err: BusinessError) => {
          // 处理业务逻辑错误
          console.error(`startServiceExtensionAbility failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // 处理入参错误异常
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startServiceExtensionAbility failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIExtensionContext.startServiceExtensionAbilityWithAccount<sup>18+</sup>

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

启动一个指定系统账号下的ServiceExtensionAbility。使用Promise异步回调。

> **说明：**
>
> 组件启动规则详见：[组件启动规则（Stage模型）](../../application-models/component-startup-rules.md)。
>
> 当accountId为当前用户时，无需进行权限校验。

**模型约束**：此接口仅可在Stage模型下使用。

**系统接口**：此接口为系统接口。

**需要权限**：ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

**系统能力**：SystemCapability.Ability.AbilityRuntime.Core

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| ------ | ------ | ------ | ------ |
| want | [Want](js-apis-app-ability-want.md) | 是 | 启动ServiceExtensionAbility的Want信息。 |
| accountId | number | 是 | 系统账号的ID，详情参考[getCreatedOsAccountsCount](../apis-basic-services-kit/js-apis-osAccount.md#getosaccountcount9)。 |

**返回值：**

| 类型 | 说明 |
| ------ | ------ |
| Promise&lt;void&gt; | Promise对象。无返回结果的Promise对象。 |

**错误码：**

以下错误码详细介绍请参考[通用错误码](../errorcode-universal.md)和[元能力子系统错误码](errorcode-ability.md)。

| 错误码ID | 错误信息 |
| ------ | ------ |
| 201 | The application does not have permission to call the interface. |
| 202 | The application is not system-app, can not use system-api. |
| 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. |

**示例：**

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

export default class UIExtAbility extends UIExtensionAbility {
  onForeground() {
    let want: Want = {
      bundleName: 'com.example.myapplication',
      moduleName: 'entry',
      abilityName: 'ServiceExtensionAbility'
    };
    let accountId = 100;

    try {
      this.context.startServiceExtensionAbilityWithAccount(want, accountId)
        .then(() => {
          // 执行正常业务
          console.info('startServiceExtensionAbilityWithAccount succeed');
        })
        .catch((err: BusinessError) => {
          // 处理业务逻辑错误
          console.error(`startServiceExtensionAbilityWithAccount failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (err) {
      // 处理入参错误异常
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`startServiceExtensionAbilityWithAccount failed, code is ${code}, message is ${message}`);
    }
  }
}
```

## UIExtensionContext.setHostPageOverlayForbidden<sup>15+</sup>

setHostPageOverlayForbidden(isForbidden: boolean) : void

是否允许[UIExtensionAbility](../apis-ability-kit/js-apis-app-ability-uiExtensionAbility.md)拉起的页面被使用方的页面覆盖。

> **说明：**
>
> 组件启动规则详见：[组件启动规则（Stage模型）](../../application-models/component-startup-rules.md)。
>
> 该接口需要在窗口创建之前调用。建议在[UIExtensionAbility](../apis-ability-kit/js-apis-app-ability-uiExtensionAbility.md)的[onCreate](../apis-ability-kit/js-apis-app-ability-uiExtensionAbility.md#uiextensionabilityoncreate)生命周期内调用。

**模型约束**：此接口仅可在Stage模型下使用。

**系统接口**：此接口为系统接口。

**系统能力**：SystemCapability.Ability.AbilityRuntime.Core

**参数**：

| 参数名 | 类型 | 必填 | 说明 |
| ------ | ------ | ------ | ------ |
| isForbidden | boolean | 是 | 是否允许[UIExtensionAbility](../apis-ability-kit/js-apis-app-ability-uiExtensionAbility.md)拉起的页面被使用方的页面覆盖。true表示不允许，false表示允许。 |


**错误码**：

以下错误码详细介绍请参考[通用错误码](../errorcode-universal.md)。

| 错误码ID | 错误信息 |
| ------ | ------ |
| 202 | The application is not system-app, can not use system-api. |
| 401 | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. |

**示例**：

```ts
import { UIExtensionAbility } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class UIExtAbility extends UIExtensionAbility {
  OnCreate() {
    try {
      this.context.setHostPageOverlayForbidden(true)
    } catch (err) {
      // 处理入参错误异常
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      console.error(`setHostPageOverlayForbidden failed, code is ${code}, message is ${message}`);
    }
  }
}
```